CN119698549A

CN119698549A - Self-tuning bubble detector assembly, calibration method, and computer program product for a diagnostic analyzer

Info

Publication number: CN119698549A
Application number: CN202380057665.3A
Authority: CN
Inventors: A·罗森菲尔德
Original assignee: Siemens Healthcare Diagnostics Inc
Current assignee: Siemens Healthcare Diagnostics Inc
Priority date: 2022-09-15
Filing date: 2023-09-14
Publication date: 2025-03-25
Also published as: WO2024059716A3; EP4587814A2; WO2024059716A2

Abstract

A self-tuning optical bubble detector assembly for a diagnostic analyzer. The bubble detector assembly has a light emitter that operates with multiple inputs (i.e., generates multiple light intensities) for dry supply line tubing (i.e., without liquid) and for wet supply line tubing (i.e., with liquid therein). Multiple outputs are generated that represent light detected through the dry supply line tubing and the wet supply line tubing. Based on the received outputs, a final calibration setting (e.g., % duty cycle setting or I_LED) and a threshold value are determined at which it is accurately and repeatedly determined whether the supply line tubing has liquid or air therein. As with other aspects, a method and computer program product for a self-tuning optical bubble detector for a diagnostic analyzer are further provided.

Description

Self-tuning bubble detector assembly, calibration method and computer program product for diagnostic analyzer

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional patent application No. 63/375,851, entitled "SELF-TUNINGBUBBLE DETECTOR ASSEMBLIES,CALIBRATION METHODS,AND COMPUTER PROGRAM PRODUCTS FOR DIAGNOSTIC ANALYZERS", filed 9/15/2022, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

Technical Field

The present disclosure relates to diagnostic analyzers, and more particularly to bubble detector assemblies and methods for use in such diagnostic analyzers.

Background

A wide variety of medical diagnostic analyzers (e.g., chemical analyzers and immunoassay devices) are used to analyze patient samples such as, for example, whole blood, serum or plasma, cerebrospinal fluid, interstitial fluid (INTERSTITIAL FLUID), urine, semen, sputum, saliva, and the like. These diagnostic analyzers typically use one or more liquid reagents, wash fluids, or other process fluids (process liquids) in conjunction with the processing of such patient samples. In order to obtain accurate diagnostic results, it may be necessary to transfer very precise amounts of liquid reagent and possibly one or more other liquids from one location (e.g. a storage container or liquid supply) to a receptacle (receptacle) in which a chemical reaction may take place, or vice versa. In many cases, the liquid transfer is performed by a probe (pipette) coupled to a length of flexible supply line tubing. Although bubble detectors are used to detect the presence of liquid in a pipe, such liquid detection may have certain performance drawbacks.

Disclosure of Invention

According to some embodiments, the present disclosure provides an optical bubble detector assembly comprising a controller configured to operate a light emitter projecting light into a supply line conduit and detecting, by 33, transmitted light through the conduit at a plurality of light intensities corresponding to a plurality of inputs, receiving a first plurality of outputs from a light detector of the optical bubble detector, the first plurality of outputs respectively corresponding to the plurality of inputs, each of the first plurality of outputs representing an amount of light detected through the supply line conduit without liquid therein, receiving a second plurality of outputs from the light detector, the second plurality of outputs respectively corresponding to the plurality of inputs, each of the second plurality of outputs representing an amount of light detected through the supply line conduit with liquid therein, and selecting a particular one of the plurality of inputs as a final calibration setting based on a selected one of the first and second plurality of outputs.

According to a second embodiment, the present disclosure describes a method of calibrating an optical bubble detector. The method includes receiving a first plurality of outputs, each of the first plurality of outputs representing an amount of light detected through a supply line pipe having no liquid therein, the first plurality of outputs corresponding to a plurality of inputs of the light emitter, respectively, receiving a second plurality of outputs, each of the second plurality of outputs representing an amount of light detected through a supply line pipe having liquid therein, the second plurality of outputs corresponding to a plurality of inputs of the light emitter, respectively, and selecting a particular one of the plurality of inputs as a final calibration setting based on a selected one of the first and second plurality of outputs.

According to a third aspect, a computer program product is provided. The computer program product includes a computer-readable non-transitory medium having computer program code configured to receive a first plurality of outputs, each of the first plurality of outputs representing an amount of light transmitted through a supply line pipe having no liquid therein for a respective plurality of inputs of the light emitter, receive a second plurality of outputs, each of the second plurality of outputs representing an amount of light transmitted through a supply line pipe having liquid therein for a respective plurality of inputs, and set a final calibration setting based on a selected one of the first plurality of outputs and the second plurality of outputs.

Other aspects, features, and advantages of the present disclosure will become readily apparent from the following detailed description, wherein various example embodiments are described and illustrated, including the best mode contemplated for carrying out the present disclosure. The disclosure is also capable of other and different embodiments and its several details are capable of modifications in various respects, all without departing from the scope of the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. The disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.

Drawings

The drawings described below are for illustration purposes only and are not necessarily drawn to scale. The drawings are not intended to limit the scope of the present disclosure in any way.

Fig. 1 illustrates a perspective view of a bubble detector assembly according to a first embodiment.

FIG. 2 illustrates a detailed schematic diagram of a first self-tuned bubble detector assembly configured to read a bubble detector, according to an embodiment.

Fig. 3A illustrates a schematic overview of a second self-tuned bubble detector assembly configured to read a bubble detector, according to an embodiment.

FIG. 3B illustrates a detailed schematic diagram of a second self-tuned bubble detector assembly configured to read a bubble detector, according to an embodiment.

Fig. 4A illustrates a first graph of the output voltage from the light detector relative to a% duty setting (duty setting) provided to drive the light emitter for a first embodiment of the bubble detector assembly according to an embodiment.

Fig. 4B illustrates a second graph of current to the light emitter versus reference voltage output from the light detector for a second embodiment of a bubble detector assembly according to an embodiment.

Fig. 5 illustrates a schematic flow diagram of a method of calibrating an optical bubble detector according to an embodiment.

FIG. 6A illustrates a flow chart of a general self-calibration method of calibrating an optical bubble detector (e.g., first and second optical bubble detectors of first and second optical bubble detector assemblies) according to an embodiment.

FIG. 6B illustrates a flow chart of a first self-calibration method of calibrating a first optical bubble detector according to an embodiment.

FIG. 6C illustrates a flow chart of a second self-calibration method of calibrating a second optical bubble detector according to an embodiment.

Fig. 6D illustrates a flowchart of a method of generating DRY and WET calibration data for DRY (DRY) and WET (WET) calibration curves of a second bubble detector calibration method according to an embodiment.

Fig. 6E illustrates a flowchart of a method of finding the i_led_final (Final calibration setting) of the second bubble detector method according to an embodiment.

Fig. 6F illustrates a flowchart of a method of determining v_ref_final of the second bubble detector method according to an embodiment.

FIG. 7 illustrates a view of a Manchester (Manchester) auto-calibrate command waveform that may be used by the bubble detector assembly according to an embodiment.

Fig. 8A and 8B illustrate enlarged and reduced views, respectively, of an auto-calibration command waveform that may be used by the second self-tuning bubble detector assembly, in accordance with an embodiment.

Fig. 9A to 9F illustrate various views of a second bubble detector assembly and components thereof according to an embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

When managing the flow of liquid, means such as bubble detectors are typically used to ensure that the desired volume of liquid has in fact moved from one location to another. This is typically performed using non-contact techniques, which may include optical techniques. Basic and regulated optical liquid/air sensors (referred to herein as "bubble detectors") are known, but they may have limited performance in diagnostic analyzers for medical applications. In particular, there is a need to provide an optical bubble detector assembly and/or a method of calibrating an optical bubble detector that can accurately and repeatedly detect the presence of certain liquids or air in a supply line conduit. Supply line conduit as used herein means any conduit for transferring liquid from one location to another. In some embodiments, an accurate amount of a small volume of liquid in a supply line tubing used in such medical diagnostic analyzers may be measured. In other applications, the presence or absence of liquid at certain locations along the supply line conduit, i.e., whether wet (including liquid) or dry (including primarily air), may be determined.

In such medical diagnostic analyzers, a probe (e.g., a pipette) coupled to and movable by a robot is typically used to aspirate (aspirate) a liquid, such as a patient sample liquid and/or a reagent liquid, and transfer the sample and/or reagent liquid to another location, and then dispense the liquid(s) into a receptacle, such as a cuvette. Thereafter, the liquid may undergo further processing and/or culturing (incubation). After the liquid(s) are transferred and dispensed, the probe may be rinsed in some cases to reduce carryover of the liquid(s) to the next diagnostic test. In some embodiments, cleaning may be accomplished by lowering the probe at a cleaning station having a receptacle or well (well) containing a cleaning liquid and drawing the cleaning liquid into the probe.

In another application, such as at a washing station of a diagnostic analyzer, a washing station probe may be used to complete washing of magnetic beads (magneticbead) contained in a vessel as part of a incubation process that is occurring on the diagnostic analyzer. The washing operation may occur at a washing station, such as, for example, on a washing or incubation ring of a diagnostic analyzer. In some embodiments, more than one such washing station may be provided on the diagnostic analyzer. In some embodiments, the cleaning liquid may be dispensed from the probe through a supply line conduit. In other embodiments, the process and/or cleaning liquid may be pumped into the probe and supply line tubing. In each case, to ensure that dispensing, aspirating, and/or cleaning operations have indeed occurred, the inventors herein have included a bubble detector assembly positioned along and coupled to a length of supply line tubing coupled to the probe. Such a bubble detector assembly may be located at a location where liquid or air determination or measurement is sought, such as near or even directly adjacent to a probe or elsewhere along a supply line conduit. Thus, a bubble detector assembly according to embodiments described herein may be configured to ensure that aspiration and/or dispensing of liquid (wash liquid, liquid reagent, or even sample) has successfully occurred.

Thus, embodiments of the bubble detector assembly, self-calibrating electronic circuits thereof, self-calibrating methods, and computer program products disclosed herein may improve the performance of such bubble detector assemblies, making them much more practical for use in demanding fluid flow monitoring applications, and particularly for use in medical diagnostic analyzer applications, particularly in the case of detecting fine transitions between very clear liquid and passing air.

In particular, in reagent liquid dispensing operations, it is desirable to transfer a precise amount of liquid reagent from a storage container to a receptacle (e.g., cuvette) in which a chemical reaction will occur, facilitating quantitative measurement of a particular analyte or substance contained in a sample. In a washing operation, one or more washing liquids may be introduced into the fluid manifold and/or the supply line conduit in order to perform a washing operation on the magnetic beads contained in the cuvette. Such a cleaning operation may be through a supply line tubing removal process and/or a cleaning liquid, and/or cleaning the reagent probe or all wetted surfaces of the probe. This may minimize or avoid carryover effects from one test to another, and/or facilitate the cleaning process. In one aspect, the present methods and assemblies may detect that the cleaning operation has indeed been performed successfully.

In some embodiments, a pump, such as a diluter (diluter) pump, may be used to transfer (e.g., aspirate and then dispense) amounts as small as 100 μl or even less of these liquid reagents. Because of the medical significance of these assays and chemical tests performed by diagnostic analyzers, in some embodiments, the delivery of a known volume of reagent should be repeated without significant error. For this reason, diagnostic analyzers may not rely solely on the ability of the pump to dispense or aspirate a known volume of reagent via open loop control. Instead, each dispensing or aspiration of reagent should be checked for correctness of the volume by one or more additional sensors, signal conditioning electronics, and/or a combination of firmware and/or software methods.

Some known medical diagnostic analyzers, such as, for example, the CENTAUR XP system available from SIEMENS HEALTHINEERS, use optical sensors to confirm that the reagent is properly delivered through the supply line tubing of the system. For reagent probes, i.e. probes for aspirating and dispensing liquid reagents, bubble detectors with light emitter/photodetector pairs have been used which enable software to ascertain (ascertain) that the correct volume was aspirated by the reagent probe from the reagent container of the analyzer and then dispensed to a receptacle (e.g. cuvette) for incubation and analysis. The diagnostic analyzer may use any suitable analyte or component detection method, such as using chemiluminescence, absorbance (absorbance), or the like. For this type of reagent aspiration, a bolus (slug) of reagent may be held in place with an antecedent air gap and a postamble air gap around the bolus in the supply line.

Since the software is instructing the pump to aspirate and/or dispense liquid reagent into and/or out of the reagent probe at specific time intervals, there is a desired time range (timeframe) over which the bubble detector will see air, followed by liquid, and then followed by air. In this way, the software can detect if the correct aliquot (aliquot) of liquid reagent is indeed dispensed, and if not, generate a flag to indicate something is wrong in the process. Potential causes of such labeling may be the exhaustion of reagents, the presence of a blockage in the supply line tubing, and/or the detection of air bubbles.

In a bulk (bulk) fluid region of a diagnostic analyzer, a bubble detector with a light emitter/light detector pair may also be used to detect the presence of one of the reagents. For example, a bubble detector may be used to detect that a reagent container (e.g., a bottle) has been exhausted and that the supply line tubing has dried.

However, in these prior art systems, the calibration process that enables differentiation between a dry supply line (dry) and a wet supply line (wet) containing a liquid (e.g., a reagent or a wash liquid) is automatic or manual by adjusting the operational settings. And while somewhat adequate, the prior art calibration systems and methods are not so robust and can take a significant amount of experimentation to have them properly calibrated. In particular, because each component may contain different structures and/or materials, or may change over time, it is desirable that such a system be self-calibrating to each slightly different component with minimal human input. Furthermore, for systems that aspirate and/or dispense very clear liquids, such as in diagnostic analyzer applications, improved calibration is needed because the optical difference between such clear liquids and air is slight.

As shown in fig. 1, a first embodiment of a bubble detector assembly 100 according to the present disclosure is shown. The bubble detector assembly 100 may have a channel 102, the channel 102 being configured to receive a supply line conduit 105 (shown in phantom) therein. The bubble detector assembly 100 may have a light emitter, which may be an LED (light emitting diode), on one of the sides 104 or 106 and a light detector, which may be a photodetector, on the other of the sides 104 or 106. When a new container of reagent liquid (e.g., a bottle or other suitable reservoir) is installed on the diagnostic analyzer, the software counter may be set to a value corresponding to the number of puffs available for that container volume. For each puff, the counter may be decremented by one. Once the counter reaches zero, the operating software may not allow further testing to run and may prompt the operator via, for example, a computer monitor to replace or refill the reagent container. The present disclosure includes a bubble detector assembly 100, the bubble detector assembly 100 including a light emitter/light detector pair at sides 104 and 106 that can act as a failsafe (failsafe) mechanism to the software counter method to ensure that the diagnostic test of the diagnostic analyzer does not run unless an appropriate amount of reagent liquid is indeed present. Thus, the bubble detector 100 may provide a safety feedback mechanism above and beyond the software counter by detecting whether reagent liquid is actually present in the supply line tubing 105. Other suitable uses of bubble detector assembly 100 in a diagnostic analyzer may include, but are not limited to, determining the presence or absence of a large number of reagents, the presence or absence of a wash liquid, the presence or absence of a process liquid, and/or liquid measurements.

In the above-described applications (e.g., bulk reagent container applications), light may be transmitted laterally (crosswise) through the supply line conduit from one side and detected by a light detector (e.g., photodiode) on the other side of the supply line conduit 105. In some embodiments, a light emitter (e.g., LED) and a light detector (e.g., photodetector) may be positioned along opposite sides of the same axis of the supply line conduit 105. In other embodiments described herein, a light emitter (e.g., LED) and a light detector (e.g., photodetector) may be positioned on one side of the conduit axis and may include reflective surfaces on an opposite side of the conduit axis.

In accordance with the present disclosure, signal conditioning circuitry configured to receive analog signals from the light detector should be configured to be able to distinguish between a dry supply line pipe (dry) and a wet supply line pipe (wet) containing a liquid (e.g., a reagent, process, or cleaning liquid). The detected output may be a function of such variables as, for example, optical alignment of the light emitter (e.g., LED) and light detector (e.g., photodetector), optical properties of the tubing due to coloration (pigmentation) and size, turbidity or color of the liquid passing through the supply line tubing 105, and possibly other factors. Note that the bubble detector alignment may and typically does vary from bubble detector to bubble detector due to at least mechanical misalignment of the light emitter and light detector. The thickness and/or opacity of the tubing may also vary at various locations along a length of supply line tubing 105. These variations may shift the wet and dry state output voltages by as much as half a volt. Thus, there is a need for a robust calibration method that can be used to properly calibrate each individual bubble detector assembly as described herein.

Some known bubble detectors may have some degree of self-calibration, but are often too limited for use with at least some diagnostic analyzers. Such prior art self-calibration capability can be based on experience with bubble detectors to simply establish a fixed operating output. The on-board circuitry may use an adjustable current source to achieve intensity control of the light emitters. During calibration, the microcontroller may incrementally adjust the intensity of light from the light emitters and read the emission voltage of the light detectors. In this way, the firmware looks for a current from one of the input settings that can drive the light emitter to the desired set point. The calibrated settings may be saved in the memory of the microcontroller so that whenever it is powered up thereafter, it will resume operation at the calibrated settings. This single case calibration may be useful in some applications, but is often insufficient for diagnostic analyzer applications involving very clear liquids.

However, in addition, this prior art method does not consider a relationship between measured voltages indicative of dry and wet tubing that is important for bubble detection in a diagnostic analyzer that determines the presence of a particular liquid in the supply line tubing 105 or otherwise quantifies the amount of liquid that has been aspirated and/or dispensed. In particular, there is a need for an improved calibration method in these applications, as liquids (e.g., reagents and wash liquids) tend to be very clear, and thus the optical difference between wet and dry readings can be very small and very difficult to detect.

Fig. 2 illustrates a first embodiment of a bubble detector assembly 100 including a self-tuning circuit according to an embodiment of the present disclosure. In accordance with one or more embodiments herein, the bubble detector assembly 100 may be operated to optimize circuit performance (tuning) for its bubble detector 202, such as, for example, an OPTEK OPB350W250Z bubble detector. The bubble detector assembly 100, which may include one or more printed circuit board assemblies, may be used with a probe (pipette) that aspirates a liquid, such as when the liquid is a liquid reagent or a wash liquid, but may be used in any analyzer (assay instrument or chemical analyzer) where it is desired to determine the presence or absence of a liquid at a location along the supply line tubing 105.

Given the variability described above, it is desirable to tune each individual bubble detector 202. Self-tuning with the bubble detector assembly 100 described herein may include the use of a calibration LED 204 and a dry/wet tubing indicator 206 (e.g., an LED) that are operable to display the calibration status and conditions (e.g., wet or dry) in the supply line tubing 105, respectively. To facilitate self-calibration, one or more button inputs (e.g., button 208) and one or more calibration outputs (e.g., LEDs) 204, 206 may be used. Following the flowcharts presented in fig. 6A and 6B, the bubble detector assembly 200 may perform a calibration/self-tuning process according to embodiments of the present disclosure.

In a first embodiment, the calibration/self-tuning method may start with the supply line conduit 105 in a dry state. A section (shown in phantom) of the supply line conduit 105 passes through the bubble detector 202. The supply line tubing 105 may be coupled to a pipette and optionally to a reagent or waste container. When a dry "calibration" sequence is initiated, the controller 210 (may beA microcontroller such as, for example, microchip Technology company PIC16F 876) may step through a full range% duty cycle setting supplied as input to the light emitter circuitry. For example, the input may be a Pulse Width Modulated (PWM) signal (or waveform) in the input line 215.

For example, the LED intensity of the light emitter 211 may be controlled by tertiary electronics. The first stage may be a PWM input from the controller 210. The input signal in line 215 may drive an RC circuit (stage 2) to convert the PWM output to a voltage. This voltage may drive the OP-AMP 218/transistor 219 pair (stage 3), resulting in an adjustable current sink (sink) from the cathode terminal of the light emitter 211. The anode terminal of the light emitter 211 may be connected to a positive circuit power supply of the circuit. As such, each% duty cycle setting of the PWM signal generated by the controller 210 corresponds to a different steady state current and thus a different intensity level emitted from the light emitter 211 (e.g., a Light Emitting Diode (LED)).

The PWM signal input in line 215 is injected into the regulated portion of the circuitry of the bubble detector assembly 100 to generate a DC voltage at the input of the OP-AMP 218. For example, the OP-AMP 218 can be a TS922 rail-to-rail dual BiCMOS operational amplifier. The signal may drive transistor 219, and transistor 219 may be a Bipolar Junction Transistor (BJT) that creates a current sink for light emitter 211. For example, transistor 219 may be a 2n222 NPN bipolar junction transistor. Each% duty cycle of the PWM waveform is related to a particular sink current of the light emitter 211. The optical signal passing through the supply line pipe 105 is converted to a DC voltage at the output pin of the optical detector 212. The detector output voltage in line 217 may be digitized with an a/D converter and stored in memory 210M of controller 210. Dry calibration involves injecting an increasing% duty cycle setting of the PWM signal to generate a range of different light intensity levels. Each output (e.g., voltage) in output lines 217 may correspond to a respective input of a% duty cycle setting of the PWM signal.

Next, the supply line tubing 105 may be wetted and a wet "calibration" sequence may be initiated, such as by pressing a button 208. As performed during the dry "calibration" routine, the wet "calibration" injects the same set of% duty cycle settings of the PWM signals into the circuit to generate corresponding intensity levels of the light emitters 211, as will be explained below. The data forming the dry and wet "calibration" curves (see 404A, 402A) are shown in fig. 4A. These curves are different due to altered light scattering that occurs between the dry calibration sequence and the wet calibration sequence due to the presence or absence of liquid in the tube at the location of the bubble detector 202.

The supply line pipe 105 may be wetted by any suitable pump or vacuum supply coupled or interconnected to the supply line pipe 105 that provides liquid into the region of the supply line pipe 105 that receives the light signal from the light emitter 211. In the case of reagent aspirating and dispensing, the supply line conduit 105 is wetted by aspirating a desired amount of reagent liquid such that the reagent liquid is present between the light emitter 211 and the light detector 212. In the case of one cleaning operation, the cleaning liquid may be aspirated from the cleaning reservoir into the pipette immersed therein. The cleaning liquid may be pumped by operation of the pump until the cleaning liquid occupies a portion of the supply line conduit 105 between the light emitter 211 and the light detector 212. In another washing embodiment, a washing probe may be lowered into a receptacle (e.g., cuvette) and used to aspirate process liquid, and/or wash magnetic beads with washing liquid, where light emitter 211 and light detector 212 may be positioned at points along supply line tubing 105 to determine whether liquid has been aspirated and/or dispensed into supply line tubing 105. The light emitter 211 and light detector 212 of the bubble detector 202 may be positioned directly adjacent to the probe or at another location along the supply line conduit 105.

In each embodiment, the controller 210 may again traverse (walkthrough) the same full range of the same% duty cycle setting of the PWM signal, as previously input in the input line 215 for the dry condition. As previously described, the measured output (e.g., voltage) from the output line 217 of the photodetector 212 may be digitized at the output of the controller 210. The digitized output voltage values resulting from each injected% duty cycle setting may be stored in memory 210M and/or sent to an external computer for analysis.

According to an embodiment, the bubble detector assembly 100 then performs an analysis to determine which particular one of the% duty cycle settings (hereinafter referred to as the "final calibration setting") achieves excellent signal separation. In particular, it is desirable to achieve a maximum separation difference between the output voltages in the wet and dry cases (see line 409 of fig. 4A). In some embodiments, the final calibration setting 407 may be a% duty cycle setting input value that provides a maximum amount (maximum) voltage difference between the recorded outputs (e.g., voltages) of the wet calibration sub-method and the dry calibration sub-method.

For example, in a so-called "max-split" embodiment (first embodiment), the controller 210 may calculate Vwet-Vdry voltage spreads (fingers) for each% duty cycle setting provided as input in line 215 and further search for a particular one of the% duty cycle settings that provides the greatest amount (max 408) of voltage spread (hereinafter referred to as the "final calibration setting"). Curve 406 is a plot of the output voltage difference in line 217 for each corresponding% duty cycle setting. Curve 402A is a plot of the wet output voltage in line 217 for wet calibration. Curve 404A is a plot of the dry output voltage in line 217 for dry calibration. This particular final calibration setting 407 may be stored in a memory 210M such as NVRAM (non-volatile random access memory). Looking forward, the final calibration setup 407 may be used to drive the light emitters 211 for excellent signal separation. The light emitters 211 may be any suitable light emitting devices, such as Light Emitting Diodes (LEDs). The light detector 212 may be any suitable photodetector.

In this embodiment, the midpoint voltage 409 between Vdry and Vwet at the final calibration setting 407 may be calculated and stored in memory 210M. This midpoint voltage 409 may be used as a firmware comparator reference (i.e., voltage threshold (V _TH)) to determine whether the supply line conduit 105 is wet, i.e., contains liquid, or dry, i.e., contains no liquid. When V _TH at line 409 is met or exceeded, the dry/wet pipe indicator 206 may illuminate, thus signaling detection of a wet pipe condition, as shown in fig. 4A. More practically, this output signal 217 to the controller 210 may be used to drive digital I/O lines of an external electronic circuit, microcontroller, or computer. The calculations may be carried out by the controller 210 and/or an external electronic circuit, microcontroller or computer, or a combination thereof. The methods and components may be responsive to detected wet or dry bubble detector conditions, such as by providing an error that may alert an operator. The flagged error may indicate that an incorrect state has been output for a particular operational stage of the ongoing process, such as, for example, aspiration or dispensing of a liquid reagent or aspiration or dispensing of a wash liquid.

In detail in fig. 2, the bubble detector assembly 100 may include an operational amplifier 218, the operational amplifier 218 being coupled to receive an input in an input line 215, which may be a Pulse Width Modulated (PWM) signal, from the controller 210. The operational amplifier 218 along with the transistor 219 may be configured to convert the PWM drive signal into an adjustable current and provide a current drive signal to the light emitter 211 that is responsive to the input in the input line 215. This supplies a variable current input to the light emitter 211, thereby controlling the intensity of light emitted by the light emitter 211, which may vary during wet and dry calibration (e.g., in stepwise increments). After calibration, the input value corresponding to the final calibration setting is used to illuminate the light emitters 211. Note that as used herein, each "% duty cycle setting" is an input proportional to the intensity level (e.g., magnitude) of the light emitted by the light emitter 211. For example, a 30% duty cycle setting of the PWM signal may correspond to an intensity level of 30% of the maximum intensity of the light emitter 211. The maximum separation calibration method described herein includes selecting the% duty cycle setting of the PWM signal supplied from the controller 210 and then selecting the comparator reference V _TH for maximum wet-to-dry output signal separation, which can be tuned to establish the most "centered" setting.

Fig. 4A illustrates a graph 400A of example calibration data for a calibration run that seeks maximum separation of wet and dry signals, according to a first embodiment. Fig. 4B illustrates a graph 400B of example calibration data for a calibration run according to a second embodiment that seeks maximum separation of wet and dry signals by examining the maximum and minimum recorded values described herein below (so-called 1/2 max-min embodiments).

The test data in fig. 4A includes a% duty cycle setting of the output voltage of the light detector 212 relative to the PWM input, which corresponds to the intensity of the light emitters 211 of the dry pipe (Vwet data curve 402A) and the wet pipe (Vdry data curve 404A). The calibration data also illustrates the voltage difference between the corresponding voltages for the wet and dry pipe conditions for each% duty cycle setting (see Δv= Vwet-Vdry data curve 406). In this example, 20 different% duty cycle settings ranging from 0% to 40% duty cycle are used to obtain a corresponding plurality Vdry and Vwet of output voltages, resulting in Vwet data curves 402A and Vdry data curve 404A. In other embodiments, other numbers and ranges of% duty cycle settings may be used as inputs. For example, a duty cycle setting of at least ten% ranging from 10% to 90% may be used. In this example, the% duty cycle setting that yields the maximum Vwet-Vdry signal separation is about 34% as indicated by point 408 on the Δv= Vwet-Vdry data curve 406.

As shown in fig. 4A, at this% duty cycle setting (final calibration setting) on line 407, the midpoint voltage between Vwet and Vdry voltages is about 2.85 volts (see line 409). In some embodiments, the midpoint voltage may be set to a threshold voltage V _TH for determining whether the pipeline conditions are wet or dry during actual non-calibrated run time, i.e., below the trigger point the supply line pipeline 105 is determined to be dry and equal to or above the trigger point the supply line pipeline 105 is determined to be wet. In other embodiments, the threshold voltage V _TH may be set to a voltage other than a midpoint between the Vwet and Vdry voltages at which the maximum voltage difference Δv occurs, such as slightly above or below the midpoint (e.g., +/-5%).

In some embodiments, the bubble detector assembly 100 and its firmware may include a small circuit board 132 to which the bubble sensor 202 is mounted (e.g., in a manner similar to known sensors). In other embodiments, if the bubble detector location on the supply line conduit 105 does not provide sufficient space for the bubble detector assembly 100, the bubble detector assembly 100 and firmware may be placed on one or more separate circuit boards.

Fig. 5 illustrates a flow chart of a method 500 of calibrating an optical bubble detector, such as the embodiments of fig. 2 and 3A-3B, in accordance with one or more embodiments disclosed herein. At process block 502, method 500 may include receiving a first plurality of outputs (e.g., dry voltage 404A in fig. 2 (first embodiment) or dry output in line 317, which may be proportional to dry current (i_led) 402B in fig. 4B (second embodiment)), each of the first plurality of outputs representing an amount of light (i.e., dry calibration mode) detected by a supply line pipe (e.g., supply line pipe 105) having no liquid therein, the first plurality of outputs corresponding to a plurality of inputs to light emitters (e.g., light emitters 211, 311), respectively. For example, for the embodiment of fig. 2 (first embodiment), the input is the% duty cycle setting of the PWM signal in input line 215, and for the embodiment of fig. 3B (second embodiment), the input is the input to DAC 320 in line 315 (scan current until the comparator voltage of comparator 319 equals each v_ref value).

Referring again to fig. 5, at process block 504, method 500 may include receiving a second plurality of outputs (e.g., wet voltage 402A in fig. 2 (first embodiment) or wet output voltage in line 317 (proportional to current (i_led) 404B in fig. 3B (second embodiment)) each representing an amount of light (i.e., wet calibration mode) detected by a supply line pipe (e.g., supply line pipe 105) having a liquid (e.g., liquid reagent or wash liquid) therein, the second plurality of outputs corresponding to a plurality of inputs to light emitters (e.g., light emitters 211, 311), respectively. For clarity, the same inputs are used for dry and wet calibration.

At process block 506, method 500 may include selecting a "final calibration setting" based on a selected one of the first and second plurality of outputs. The selected outputs may be selected from the corresponding pairs of dry and wet outputs such that they achieve maximum signal separation. For example, in a first embodiment, a particular one of the plurality of% duty cycle setting inputs in the input line 215 of fig. 2 is associated with a particular one of the plurality of outputs (pairs of output voltages for wet and dry conditions) in fig. 2 (see also fig. 4A). The selected output may be the corresponding output of a pair of dry and wet voltage values at a particular% duty cycle setting (final calibration setting). Also, in the second embodiment, a particular one of the plurality of voltage inputs in the input line 315 of fig. 3B is associated with a particular one of the plurality of voltage outputs (corresponding to the pair of i_led values for dry and wet cases-see fig. 4B). The controller 210, 310 may be configured to operate the light emitters 211, 311 in a final calibration setting at run time for detecting whether the supply line conduit 105 contains liquid (e.g., liquid reagent or wash liquid), i.e., is (wet) or not (dry). In the embodiment of fig. 2 (first embodiment), the final calibration setting selected may be selected based on achieving a maximum difference Δv between the wet output and the dry output. For the embodiment of fig. 3A-3B (second embodiment), the final calibration setting selected may be based on the minimum of the dry curve and the maximum of the wet curve in fig. 4B.

At process block 508, the method 500 may further include setting a threshold (e.g., V _TH) based on a selected one of the first and second plurality of outputs. The threshold may be selected to be at a midpoint between the wet output level and the dry output level of the final calibration setting (e.g., between the first voltage 404A and the second voltage 402A of fig. 2 and between the first current 402B and the second current 404B of fig. 3B). In one example, for the first embodiment, the threshold voltage 409 may be set at a voltage value at which a maximum voltage difference (Δvmax) occurs between the first and second plurality of voltages (i.e., the maximum difference at 408 in fig. 4A).

In another embodiment, the controller (state machine) 310 and method 500 may be operable, as shown in fig. 3B and 4B, to select a maximum current (i_led_max) corresponding to the first plurality of outputs and to select a minimum current (i_led_min) corresponding to the second plurality of outputs, and then to set the final calibration setting 409 to a current value that is between the maximum current (i_led_max) and the minimum current (i_led_min). For example, as shown in fig. 4B, the final calibration setting 409 may include a current i_led setting that is approximately midway (midway) (50%) between the maximum current (i_led_max) and the minimum current (i_led_min). The order of running the dry calibration and the wet calibration may be reversed.

In the embodiment of fig. 4B, method 500 may include, via operation of controller (state machine) 310, setting a light emitter (e.g., light emitter 311) to operate at a selected final calibration setting (e.g., final calibration setting 409). In particular, the final calibration setting 409 may correspond to a setting that may occur halfway (50%) between i_led_max and i_led_min.

The method 500 may further include setting a comparator threshold (e.g., v_ref_final 409) based on the selected one of the first and second outputs. In particular, method 500 may set a threshold voltage (e.g., V _TH) to a voltage value equal to v_ref_final. In other embodiments, V _TH may be set to a voltage value slightly above or below v_ref_final, such as +/-1v_ref division (division). V _TH for the fig. 3A and 4B embodiments may be set based on the midpoint between the intersections E and F between the final calibration setting line 409 and each of the wet curve 404B and the dry curve 402B.

The magnitude of the respective plurality of v_ref inputs of the second embodiment may vary from a minimum value to a maximum value (e.g., from 0 to 15v_ref increments). The plurality of inputs of each embodiment may include at least 10 different input settings (e.g., a% duty cycle setting or a v_ref setting) that generate a variable light source current that is steady state once finalized. Then, in each embodiment, V _TH may be selected for the final calibration setting, resulting in the maximum signal separation (fig. 4A and 4B).

For the second embodiment, a 2-step process (see FIG. 4B) may be employed. Here, the light emitter 311 may be pulsed at a 12.5% duty cycle setting, but the current may be provided as a 10-bit variable signal from 3mA to 85mA (always at this fixed% duty cycle setting of PWM). The i_led_final 409 is provided based on v_ref_final 407, which v_ref_final 407 is carefully selected from a selection of a plurality of discrete levels (e.g., 16 discrete levels from 1 to 15) to allow wet/dry state discrimination with a comparator threshold V _TH that is approximately centered in the possible operating band between i_led_max and i_led_min. Both embodiments achieve the same final objective of achieving maximum noise immunity (immunity) by separating as much as possible the wet and dry outputs and centering the V _TH setting as much as possible.

Once calibrated for individual supply line pipes 105, positioning, and liquid containing (wet) and non-liquid containing (dry) modes, then may include operating light emitters 311 at intensities corresponding to final calibration settings (e.g., final calibration settings 407) in order to accurately detect supply line pipes 105 having no liquid therein and supply line pipes 105 having liquid therein. If the output from the light detector 312 in the output line 317 is equal to or above the threshold, the supply line pipe 105 is determined by the controller (state machine) 310 to be wet (having liquid therein), and if the output from the light detector 312 in the output line 317 is below the threshold, the supply line pipe 105 is determined to be dry (having no liquid therein).

In each embodiment, the method may include storing a value representing a threshold value (e.g., voltage V _TH) in the nonvolatile memory 310M of the controller 210, 310. The threshold value may be used in conjunction with a generated operating parameter (e.g., voltage 409 or i_led 409) that is 1) for the first embodiment, at a maximum voltage difference (av_max) between the first plurality of voltages 404A and the second plurality of voltages 402A, or 2) selected for the second embodiment in conjunction with i_led409 (v_ref), the i_led409 being located between the maximum current input (i_led_max) and the minimum current input (i_led_min) of the first plurality of currents 404B and the second plurality of currents 402B, respectively.

Some of the above-described process blocks of method 500 may be performed or practiced in an order or sequence that is not limited to the order and sequence shown and described. For example, in some embodiments, process block 504 may be performed prior to process block 502.

Fig. 6A illustrates a flow diagram showing a general method 600A of calibrating an optical bubble detector (e.g., bubble detector 202, 302) in accordance with one or more embodiments of the present disclosure in greater detail. The method 600A begins at process block 601 by turning on a unit (e.g., bubble detector assembly 100, 300). At decision block 603, a desired calibration mode (wet calibration mode or dry calibration mode) is selected. For example, the calibration mode may be selected by actuating (e.g., holding down) a calibration button (e.g., calibration button 308), which may be any suitable switch. Alternatively, once a calibration start (calibration) command is received, it may occur in an automatic sequence (e.g., dry then wet calibration), or vice versa. The calibration LED (e.g., calibration LED 204) may be illuminated when the bubble detector assembly (e.g., bubble detector assembly 100) performs the calibration/self-tuning method 500. Other mechanisms or methods for initiating dry and wet calibration may be used.

By receiving the signal on output line 217 or 317, the start of the wet or dry calibration mode may optionally be confirmed in either of process blocks 605. For each respective one of the inputs supplied on the input lines 215, 315 (e.g., a% duty cycle setting or other input value), the output obtained may be the calibration data (Cal data) value in block 607D or the wet calibration data (Cal data) value in block 607W when the dry calibration mode is performed. In a first embodiment, the inputs may be PWM signals with different% duty cycle settings. For example, the on-duration of the various supplied% duty cycle settings may be increased in 1% or 2% increments from 0% to maximum% in the desired range. Other suitable increments may be used. The output data may be a plurality of voltages, where each voltage represents the amount of light detected by the supply line conduit 105 having no liquid therein (i.e., dry) and then having liquid therein (i.e., wet). Each of the dry calibration values and the wet calibration values in the output lines 217, 317 correspond to an input of the plurality of inputs to the light emitter 311 provided in the input lines 215, 315, respectively.

Each of the wet and dry calibration mode values may be stored in memory 210M, 310M, such as NVRAM or other suitable memory types, and/or may be forwarded to an external processor, microprocessor, or computer (e.g., computer 316). Once the dry and wet cal data points are acquired in blocks 607D, 607W, the method 600A may then optionally confirm to the user in process block 609 that each of the dry and wet data collections has been completed individually. Process block 611 (if optionally used) may further verify that the collected calibration data points are, for example, monotonically increasing, and that both dry and wet calibration have been completed. If increasing the input of the% duty cycle setting (first embodiment) or increasing the i_led (second embodiment) does not produce an increased output in lines 217, 317, something fails and the entire routine may be aborted.

The method 600A, via the controllers 210, 310 (or other computers (e.g., computer 316) connected thereto), may then perform an analysis of the dry and wet cal data points acquired and stored in memory (e.g., in memory 210M or other memory) in process block 613. The analysis involves determining which of the multiple inputs in lines 215, 315 provides excellent signal separation between wet and dry. For the first embodiment, the input 407 that causes the maximum voltage separation (Δv_max between the dry data 404A and the wet data 402A) is found. In a second embodiment, a specific v_ref value 407 is found, which results in finding an equal voltage difference between i_led_max for wet data and i_led_min for dry data.

After the analysis in block 613 is complete, the method 600A may perform an optional data check in block 615 to query whether the collected data is sufficient. This can test whether the maximum voltage separation (Δv_max) is above a preselected value or whether the input (i_led_min) is above a preselected minimum value. For example, a maximum voltage separation of at least 100mV may be desired, or a minimum current (I_LED_Min) of 10mA may be desired. If the data is insufficient (N), there may be insufficient signal strength to maintain a high signal-to-noise ratio or to establish an appropriate comparator reference. When the data is sufficient (Y), in block 621 the specific input settings that caused the desired output ("final calibration settings") are stored in the memory 210M, 310M and included for wet and dry differentiation (after the self-calibration method 500 is completed) by the bubble detector assembly 100, 300 of the bubble detector 202, 302 advancing in the run mode.

Further, in block 621, a threshold value may be selected as a comparator threshold value that determines whether a wet or dry condition exists when going into a run mode (non-calibration mode). For example, in some embodiments, the selection may be determined as V _TH. For example, in a first embodiment, the threshold V _TH may be the midpoint of the maximum voltage separation (Δv_max) and be used as the comparator threshold V _TH that is advanced in the run mode. The comparator threshold V _TH may be saved to the memory 210M. In some embodiments, the comparator threshold V _TH is a carefully selected v_ref_final setting from a preselected setting. Here again, this value may be selected as close as possible to the midpoint between the line 409 and the intersections E and F of the wet and dry data of the curves 404B, 402B, resulting in a value 407. Different thresholds than these midpoint values may be used.

As shown in block 623, the bubble detector assembly 100, 300 including the bubble detector 202, 302 is now calibrated and may be operable in a run mode. For example, the dry/wet pipe indicator 306 may now be "on" for a dry condition in the supply line pipe 105 and "off" for a wet condition in the supply line pipe 105 (or vice versa). Other mechanisms for marking wet or dry conditions may be used, such as sending a wet or dry signal to a computer (e.g., computer 316) interconnected with the bubble detector assemblies 100, 300.

Fig. 6B illustrates a flow chart showing a method 600B of calibrating a bubble detector assembly 100 including a bubble detector 202 as shown in fig. 2, in accordance with the present disclosure. As previously described, the method 600B begins at process block 601 by turning on a cell (e.g., the bubble detector assembly 100). At decision block 603, a desired calibration mode (either a dry calibration mode or a wet calibration mode) may be selected. For example, the calibration mode may be selected by actuating (e.g., pressing) the calibration button 208, which calibration button 208 may be any suitable switch. The calibration LED 204 may be illuminated when the bubble detector assembly 100 performs the calibration method 600B. For example, 1 flash of LED 204 may indicate that a dry calibration is to be performed, while 2 flashes may indicate that a wet calibration is to be performed. The calibration button 208 may be released immediately after the desired mode (wet or dry) is indicated. In one example, one periodic slow flash may indicate that a dry calibration mode is being entered, while two periodic slow flashes may indicate that a wet calibration mode is being entered. Other suitable indications may be employed.

Assuming that the first calibration mode entered is the dry calibration mode, a press of button 208 may initiate issuance of multiple inputs from controller 210 as% duty cycle settings and acquisition of the resulting associated output voltage from light detector 212. In block 607D, the output voltage may be provided as an a/D input to the controller 210. All of these digitized dry calibration values may be stored in an array internal to the controller 210 (e.g., microcontroller). When each respective one of the% duty cycle settings of the PWM signals supplied in input line 215 is DRY calibrated, each PWM signal having a different% duty cycle setting, the obtained voltage value may be the v_dry value in block 607D. The v_dry value may be referred to herein as a first plurality of voltages, where each voltage represents the amount of light detected through the supply line conduit 105 where there is no liquid (i.e., DRY). Each v_dry data value in output line 217 corresponds to an input of a plurality of% duty cycle settings from input line 215 to light emitter 211, respectively.

When the second entered calibration mode is the wet calibration mode, the same plurality of inputs for the% duty cycle setting are issued from the controller 210. Now, however, the acquired v_wet output voltage in 607W is on a different curve, because the medium inside the supply line pipe 105 will have changed, thus providing a relatively different refractive index. All of these digitized wet calibration values may be stored in an array internal to the controller 210. For example, the value of v_wet in output line 217 may be a second plurality of voltages.

The passage of air or liquid may optionally be confirmed by an operator or by other suitable means in any of process blocks 605 prior to acquiring calibration data in each of the dry and wet conditions. Once the v_dry and v_wet data (calibration data) are acquired, the method 600B may then optionally confirm to the user in process block 609, via flashing (e.g., three flashes) of the calibration LED 204 or other suitable means, that the DRY and WET data collection has been completed separately. The method 600B may then determine in process block 611 that both dry calibration and wet Calibration (CAL) have been completed.

Once completed, the method 600B, via the controller 210 or an external controller (e.g., an external processor, microprocessor, or computer) interconnected with the controller 210, may then perform an analysis on the v_dry and v_wet data in process block 613. The v_dry and v_wet data may be stored in memory 210M and/or forwarded and analyzed by controller 210 or sent to an external controller (e.g., an external processor or computer) for analysis. In some embodiments, some portions of the analysis may be performed by the controller 210, while other portions may be performed by an external controller.

In this first embodiment (the "maximum difference" embodiment), the analysis may include determining which of the multiple inputs of the% duty cycle setting provided in line 215 causes the maximum voltage separation (the maximum difference between v_wet and v_dry). This may involve calculating the difference between the outputs of v_wet and v_dry (Δv=v_wet-v_dry) for each input of PWM signals having different% duty cycle settings. Each difference av is then analytically compared in order to select the maximum difference av_max between the corresponding wet and dry data pair. The output of the light detector 212 may be connected to an analog input pin of the controller 210, where the signal may be digitized and read into a maximum difference determination program configured to derive Δv_max. The maximum difference seeking procedure may be a routine executed locally on the controller 210 or externally to a suitable controller (e.g., a processor, microprocessor, or computer).

After the analysis in block 613 is complete, method 600B may optionally query whether there is sufficient voltage separation (Δv—max) to calculate the maximum separation in block 615. For example, a voltage separation Δv—max of at least 100mV may be desired. If there is optionally a sufficient voltage separation DeltaV_Max (Y), three flashes (e.g., periodically slow flashes) or other suitable indications may be sent to the calibration LEDs 204 to indicate and confirm this. If the optional inquiry for the voltage separation ΔV_Max is not sufficient (N), a continuous flash or another suitable indication may be sent to the calibration LED204 to indicate the error condition. When the voltage separation (Δv) is not sufficient (N), there may be insufficient signal strength to keep the signal-to-noise ratio high or to establish a suitable comparator reference.

When the voltage separation Δv_max is sufficient (Y), in block 621, the particular% duty cycle setting ("final calibration setting"), i.e., the particular% duty cycle setting that caused the maximum difference Δv_max, may be stored in memory 210M and may then be used as an input to wet and dry determinations of bubble detector assembly 100 including bubble detector 202 that is advanced in the run mode after self-calibration method 600B.

Further, in block 621, a threshold voltage may be selected. For example, the selection may be calculated as the midpoint of the maximum voltage separation (Δv—max) and used as a comparator threshold V _TH reference, proceeding to determine the trigger point between the wet and dry determinations. The comparator threshold V _TH may be saved to the memory 210M. Other comparator thresholds V _TH than the midpoint may be used. For example, the comparator threshold V _TH may be a 0.48x midpoint, or another fraction (fraction) of Δv_max, such as +/-5% of the midpoint. This midpoint voltage, which is a comparator threshold, may be used as a comparator threshold V _TH of the firmware program for setting its output state LED to an "on" state for dry or an "off" state for wet (or vice versa).

As shown in block 623, the bubble detector assembly 100 including the bubble detector 202 is now calibrated and operable in the run mode. As shown in fig. 4A, if any measured voltage is equal to or above threshold voltage V _TH (line 409), it is determined to be a wet condition in supply line pipe 105, and below line 409 is determined to be a dry condition.

Fig. 6C illustrates a flow chart of a second method 600C of calibrating the optical bubble assembly 300 in more detail. This method 600C is referred to herein as the 1/2 max-min method herein. This second method 600C may be implemented by the bubble detector assembly 300 of FIGS. 3A-3B and 9A-9F herein. In this method embodiment, the reflective bubble detector 302 is used to optically sense the difference between the dry condition of the supply line pipe 105 (with no liquid therein) and the wet condition of the supply line pipe 105 (with liquid therein).

The second method 600C begins at process block 601 by turning on a unit (e.g., bubble detector assembly 300) as before. At decision block 603, a desired calibration mode (either dry calibration mode or wet calibration mode) is selected. For example, the calibration mode may be selected by sending a calibration command (calibration) to the bubble detector assembly 300 or other suitable starting method, such as through the basic I/O board 303 from the interconnected external computer 316. Alternatively, once a calibration start command is received, the selection order may occur in an automatic sequence (e.g., dry then wet calibration) in some embodiments, or vice versa. Once the bubble detector assembly (e.g., bubble detector assembly 300) successfully completes the calibration method 600C, an acknowledgment signal in block 605 may be received, such as through the basic I/O board 303.

The start of the wet calibration mode or the dry calibration mode includes passing air or liquid (e.g., liquid reagent, cleaning liquid, or process liquid) through the supply line conduit 105 at the location of the bubble detector 302. The optional validation in block 605 may be accomplished by receiving a test signal, such as by measuring supply line pressure, or other suitable means. For each of the dry calibration mode and the wet calibration mode, I_LED data is acquired in blocks 607D and 607W. When dry calibration mode is performed for each respective one of the corresponding inputs supplied on input line 315, the acquired output may be the calibration data (Cal data) value in block 607D. For example, the v_ref value may range from a low voltage to a high voltage (e.g., from 245mV to 676 mV). The drive current to the light emitters 311 may range, for example, from about 3mA to about 85mA. In this method 600C, calibration is performed at each reference voltage (v_ref) value available for use. Thus, a multi-point method is provided that scans across available reference voltage inputs to generate voltage output data that forms a wet calibration curve and a dry calibration curve.

As shown, 15 different v_ref levels are provided for use as comparator voltage values that increment in magnitude from a lowest value to a highest value in approximately equal increments during each calibration mode (wet and dry calibration). Each v_ref setting is used as a target voltage by the controller (state machine) 310 because the current ramps up (ramp) from 3mA to 85mA during each calibration. The optical receiver 312 receives the reflected light and provides voltage feedback to the controller 310 via an output line 317 and a comparator 318. Once the ramped feedback output voltage at output line 317 reaches the incremental target voltage V_Ref value, the associated I_LED is recorded.

The output data in output line 317 may be a plurality of voltages (or currents), with each output representing the amount of light detected at each v_ref setting by supply line pipe 105 with no liquid therein (i.e., dry calibration) or when there is liquid therein (i.e., wet calibration). Each dry calibration value in output lines 317 may be a first plurality of outputs corresponding to a plurality of inputs from input lines 315 to light emitters 311, respectively.

The wet calibration value in output line 317 may be a second plurality of outputs, where each output represents the amount of light detected through supply line pipe 105 having liquid therein (i.e., wet calibration). Each Cal data value acquired as output in block 607W corresponds to a plurality of inputs from input line 315 to optical transmitter 311, respectively. Each of the wet and dry calibration mode values may be stored in a memory 310M, such as NVRAM or other suitable memory type, and/or transmitted to the computer 316.

Once the dry and wet cal data points are acquired in blocks 607D, 607W, the method 600C may then optionally complete with the individual confirming each of the dry and wet data sets in process block 609. The method 600C may then determine in process block 611 that both the dry calibration and the wet calibration have been completed.

The method 600C, via the controller 310 or the computer 316, may then be performed in process block 613 and perform an analysis of the dry and wet cal data points acquired and stored in memory (e.g., in memory 310M or the memory of the computer 316). This analysis may be performed in the computer 316 or the controller 310 to determine which of the multiple inputs in the line 315 provides excellent signal separation between wet and dry conditions. For example, in this embodiment, once the FINAL calibration setting i_led_final is determined, the maximum v_ref separation between dry and wet data may be determined (as shown in fig. 4B).

After the analysis in block 613 is complete, the method 600C may perform an optional data check in block 615 to query whether the collected data is sufficient. This can test whether i_led_min is above a preselected minimum current. For example, a minimum current of 100mA (i_led_min) may be desired. If the data range is insufficient (N), there may be insufficient signal strength to maintain a high signal-to-noise ratio or establish a proper comparator reference.

When the data is sufficient (Y), in block 621, the Final calibration setting (i_led_final) that caused the desired output is stored in memory 310M and used as the current supplied to light emitter 311 for determination by the wet and dry of bubble detector assembly 300 including bubble detector 302 that is advanced after self-calibration. As discussed herein, i_led_final may be calculated to be equal to (i_led_max+i_led_min)/2. From the i_led_final, the corresponding v_ref can be estimated.

Further, in block 621, a comparator threshold may be selected that determines whether a wet or dry condition exists when going into the run mode (non-calibration mode). For example, in some embodiments, the selection may be determined as V _TH. For example, V _TH may be equal to v_ref_final. V_ref_final may be the midpoint 407 of the measured voltage separation (v_ref_final= (WETVREFINTERCEPT + DRYVREFINTERCEPT)/2) and is used as the comparator threshold V _TH that is advanced in the run mode. The comparator threshold V _TH may be saved to memory 310M or other suitable memory. As shown on fig. 4B, the comparator threshold V _TH may be set at a voltage midway between WETVREFINTERCEPT E and DRYVREFINTERCEPT F. Other comparator thresholds V _TH than the midpoint value, such as some other fraction of v_ref_final, may be used. The selected v_ref_final value may be the v_ref increment closest to the midpoint value.

As shown in block 623, the bubble detector assembly 300 including the bubble detector 302 is now calibrated and is now capable of operating in a run mode. The dry/wet pipe indicator 306 may now be "on" for dry conditions detected in the supply line pipe 105 and "off" (or vice versa) for wet conditions detected in the supply line pipe 105 in the run mode. Other mechanisms for marking wet or dry conditions may be used, such as sending a wet or dry signal to a base I/O board 303 or other controller (e.g., microprocessor, processor, or computer 316) interconnected with the bubble detector assembly 300.

Fig. 9A-9E illustrate various views of an embodiment of a bubble detector assembly 300 including an optical bubble detector 302 and its components in accordance with one or more embodiments. The supply line conduit 105 (shown in cross section (cut) in fig. 9A, 9E and 9F for illustration purposes) is disposed in a defined position relative to the bubble detector 302, as will be described herein. The bubble detector assembly 300 may include a calibration LED to show when calibration is in progress and/or a wet/dry indicator (e.g., a wet/dry indicator LED 306 as shown in fig. 3B). Alternatively, all status indications and data compilations may be provided to the basic I/O board 303 by SPP interface circuitry 301. The basic I/O board 303 may be part of the computer 316 or its peripheral devices that may be used to receive data and perform analysis and may also provide input instructions and calibration commands to the bubble detector assembly 300 via the SPP interface circuitry 301.

Method 600C may be performed by bubble detector assembly 300 shown in fig. 3A and 3B and fig. 9A-9F. As described above, method 600C is operable to test (e.g., scan) a bubble detector (e.g., bubble detector 302) across a range of reference voltages input to light emitter 311 and record a corresponding automatically calculated i_led level determined to be necessary to drive light detector 312 to achieve a desired v_ref value, as shown in fig. 4B. The automatic calculation of the i_led current set by each v_ref input is a process by which the i_led ramps up from 3mA to 85mA until the photodiode output feeding the plus input of the comparator 319 is equal to the reference voltage (Vref) feeding the comparator's "-" input. Once the output of the photodetector 312 reaches the level of v_ref, the comparator output switches from low to high. The i_led for that particular v_ref is then latched into the NVRAM register or otherwise saved. When all 16 v_ref values (including zero) are tested, the method is performed at each v_ref setting, with liquid or air always inside the supply line pipe. These (v_ref, i_led) data pairs may be saved in the controller 310 and/or computer 316 and may then be analyzed in block 613 to determine final calibration settings and comparator threshold V _TH to achieve excellent signal separation for the particular bubble detector 302 used, noting that each such bubble detector 302 may be slightly different from one another.

Once this analysis in block 613 is complete, the values for i_led_final and v_ref_final may be written to memory (e.g., flash memory, such as EEPROM 310M or other memory type) that may be part of bubble detector assembly 300. Alternatively, the data and analysis to determine such values for I_LED_Final and V_REF_Final may be carried out by a controller (e.g., microprocessor, processor or computer 316) interconnected to the basic I/O board 303 (FIG. 3B) and external to the bubble detector assembly 300. The bubble detector assembly 300 may include, for example, an OPB9000 reflective optical sensor integrated circuit available from TT electroronics/OPTEK techenology as an adaptive sensor integrated circuit 307 (hereinafter referred to as "ASIC 307").

The bubble detector assembly 300 (and bubble detector 302) may be configured to operate with an optically transparent or translucent tube, such as Fluorinated Ethylene Propylene (FEP) material, as the supply line tubing 105, or the like. The supply line conduit 105 may have dimensions such as an outer diameter of 2.54mm, an inner diameter of 1.52mm, and may have a wall thickness of 0.51 mm. However, the bubble detector 302 may be adapted to use other tube sizes and types. The supply line tubing 105 may be fluidly connected at one end to a probe 945 by a connector 940, as shown in fig. 9A. The other end of the supply line conduit 105 (shown truncated for illustration purposes between the connector 940 and the bubble detector assembly 300) may be connected to a liquid coupling 942, which liquid coupling 942 may be connected to a dispenser, valve and/or pump, which in turn is coupled to a reservoir 943.

Depending on the application, the reservoir 943 may be a waste container (which may be held under vacuum) and waste liquid may be aspirated from a receptacle 944 (e.g., cuvette) through the probe 945 when the valve is opened or the pump is operated. In the depicted embodiment, the connector 940 at the end of the supply line tubing 105 is connected to a probe 945, which probe 945 may be movable by a robot 946 (e.g., including a stepper motor or the like), which robot 946 (e.g., including a stepper motor or the like) is configured to control movement of the probe 945, such as by lowering the probe 945 into the receptacle 944 to empty the liquid 944L therein. The liquid may be a cleaning liquid and/or a process liquid.

In some embodiments, a connector 942 at the other end of the supply line tubing 105 may be connected to a flexible/collapsible tubing (e.g., silicone-rubber tubing) that may be pinched shut with a pinch valve (pinchvalve) 946. The tubing runs forward from pinch valve 946 to a reservoir 943 (e.g., waste bottle) that may be held under vacuum (e.g., negative pressure) to pull (pull) liquid 944L into probe 945 and pull liquid 944L from probe 945 when pinch valve 946 is opened.

In other embodiments, the system may be configured to dispense a liquid (e.g., a liquid reagent, a cleaning liquid, or the like) into a receptacle 944, such as a cuvette. In such dispensing operations, the bubble detector assembly 300 may be positioned directly adjacent to a probe (such as probe 945) in order to minimize the distance between the bubble detector 302 and the probe.

In more detail, the bubble detector assembly 300 is configured to provide a wet/dry output signal to determine whether liquid (wet) or no liquid (dry) is present in the supply line conduit 105 at a desired such determined location along the supply line conduit 105. The output may be provided at J1 of the interface circuit 301 (see fig. 3A) and may be carried by an interface cable 303C connected to the SPP interface 303I.

In some applications, as discussed above, the bubble detector assembly 300 is designed to provide, for example, confirmation that the cleaning liquid has been aspirated and/or dispensed by the probe 945 at the cleaning station. The probe 945 and the cleaning station may be part of a cleaning ring assembly of a diagnostic analyzer (e.g., an immunoassay instrument or a chemical analyzer). In other embodiments, a probe (such as probe 945 of fig. 9A) may be part of a probe assembly and robot that dispenses liquid reagents into a culture receptacle (e.g., cuvette or cup) that resides in a culture ring.

In more detail, the bubble detector assembly 300 may be equipped with a highly integrated optical reflective bubble detector 302 capable of detecting moving liquid and air masses in the supply line conduit 105. For example, the bubble detector 302 may have a very low (e.g., 6 μs) response time. As will be apparent below, the bubble detector assembly 300 operates to automatically calibrate the supply line tubing 105 used, which supply line tubing 105 is constrained in a specially designed mounting assembly, as best shown in fig. 9A-9F.

The backing member 936 (fig. 9A and 9B) and stand off 930 (fig. 9E-9F) of the assembly help to maintain the supply line conduit 105 properly positioned and secured against movement relative to the bubble detector assembly 300 and further provide a highly reflective surface 302R attached to a plate 933 behind the supply line conduit 105 to provide maximum light reflection to the light detector 312. The supplied light may be Infrared (IR) light from the light emitters 311. The detected light may be amplified and compared to a determined threshold to provide a discrete comparator output. In this way, the bubble detector assembly 300 can distinguish between wet or dry conditions inside the supply line conduit 105 in the operational mode after calibration.

As shown in fig. 3B, the functional operation of the bubble detector assembly 300 can be broken down into the following functional blocks:

1) Serial Peripheral Port (SPP) interface circuitry 301 including ID EPROM 313,

2) Local voltage regulation 305, and

3)ASIC 307。

Referring again to FIG. 3B, a simplified functional diagram of the bubble detector assembly 300 can include an SPP interface 301, the SPP interface 301 designed to interface with an SPP port 303I of a basic I/O board 303, which basic I/O board 303 can interface with a computer 316. The SPP interface 301 is operable to extend the functional features of the ASIC 307. J1 of fig. 3A is an SPP interface connection to ASIC 307, which may provide power and control thereof. The basic I/O board 303 and the bubble detector board 932 (fig. 9A) share the SPP interface 303I.

The basic I/O board can manage advanced bubble detector functions through the SPP interface 303I. Low-level functions such as automatic calculation of the i_led for a given v_ref may be managed by ASIC 307. As described herein, the ASIC 307 may have a discrete light emitter 311 (e.g., an IRLED) and a discrete IR light detector 312 (e.g., a photodiode) mounted therein. Sensor sampling rates of 1Hz to 1KHz may be used. The bubble detector 302 includes an IR photoelectric pair (e.g., light emitter 311 and light detector 312) aimed at the supply line conduit 105. A reflective surface or film 302R (fig. 9C-9D) may be positioned on the opposite side of the supply line conduit 105 from the light emitter 311 and the light detector 312. As shown, the reflective surface 302R may be suitably mounted to the back of the backing member 936 and enter through a hole 936H formed therein. The drawing of the wet and dry calibration curves and subsequent calculations performed on the data to determine i_led_final and v_ref_final may be performed by the controller 310 and/or the computer 316. The computer 316 may send commands, such as SET_CONFIG, GET_CONFIG, READ_OUTPUT, and CALIBRATE, to the ASIC 307 through the SPP interface circuit 301.

The output signal from the light detector 312 in the output line 317 is a signal proportional to the reflected IR light that changes the intensity level based on whether air (dry) or liquid (wet) is contained in the supply line conduit 105. Power may be supplied from the basic I/O board 303. The bubble detector assembly 300 may provide a 3.3V push-pull compatible logic or open-drain (open-drain) output. The discrete output logic may be configured to generate HIGH (HIGH) for dry and LOW (LOW) for wet, or vice versa. The definition of the pins for the SPP interface 301 is shown in Table 1 below herein.

TABLE 1 SPP interface Pin interpretation

As shown in table 1 above, the signal direction of the supply is relative to the base SPP 303I. Communication with the bubble detector assembly 300 may be achieved through SPP interface circuitry 301 using a combination of SPI serial protocol and basic I/O polling methods. Although communication with SPI EEPROM 310M can follow the SPI protocol, communication with controller 310 (e.g., the illustrated state machine) of ASIC 307 can use a 1-wire interface and Manchester protocol. Fig. 7 shows an example encoding of a calibration request, and in particular manchester encoding of a calibration command.

Communication with registers of ASIC 307 may be accomplished through this interface. EEPROM 310M may be a type of non-volatile memory that may be used to store calibration data and may allow individual bytes to be erased and reprogrammed. It may also be used to store the identity and revision level of the PCA. The state machine of the controller 310 is hardware that can execute a behavior model and output several states. The model may include a finite number of states and is therefore also referred to as a Finite State Machine (FSM). Based on the current state and a given input, the state machine performs a state transition (transition) and produces an output.

The SPP interface circuit 301 provides power to the ASIC 307 and also provides digital communication lines. +5.3V power enters SPP interface circuit 301, which +5.3V power may be immediately converted to +3.3V by a Low Dropout (LDO) voltage regulator (LDO) 309. LDO 309 is a type of power integrated circuit that can output a stable voltage from a supply input voltage that may have some variability. ASIC 307 may consume approximately 16mA of current in operation.

SPI communication and SPI_GEN lines, labeled as part of SPP interface circuitry 301 of FIG. 3B, are used to communicate with ASIC 307 and with ID EEPROM 313. SPI_CS_flash is dedicated to ID EEPROM 313.Spi_ GENL is used to direct data to and from ASIC 307. To understand this basic function, ASIC 307 is explained in detail below.

ASIC 307 is an Integrated Circuit (IC) of a Surface Mount Device (SMD) package. Its function is to detect the presence or absence of an object via optical reflection. As shown in fig. 3B, when powered and equipped with pull-up resistors attached to their OUT and Cal-Stat lines, ASIC 307 may provide a High (HI) or LOW (LOW) discrete output signal (from the OUT pin) depending on whether the reflective surface of the reflective target is present or absent directly in front of it. In this diagnostic device application described herein, ASIC 307 may be configured for push/pull mode versus open drain mode. All logic levels for I/O with ASIC 307 are referenced to +3.3V.

Although ASIC 307 may operate as is (as-is) off-the-shelf (offthe shelf) for basic operation with robust reflective target items, the use of ASIC 307 such as for detecting the presence of a generally clear liquid in supply line pipe 105 to a less reflective surface benefits from the special calibration provided by the inventive methods described herein. All communication with ASIC 307 is via 2 digital pins OUT and Cal-Stat. While ASIC 307 operates as a sensor most of the time, with discrete outputs from the OUT pin, it also allows access to internal registers via the Cal-Stat and OUT pins.

In most cases, the serial command is sent to ASIC 307 via the Cal-Stat pin and received serially from ASIC 307 via the OUT pin. When ASIC 307 is not processing any command, the OUT pin provides a function that enables the state of the output bubble detection function, i.e., high for air and low for water. However, when a command is sent and an internal register of ASIC 307 is accessed, the Cal-Stat pin receives the write, read and calibrate commands. When a read command is issued, the register contents may be dumped (dump) via the OUT pin. For a calibration command, ASIC 307 may generate replies on the same pin, so the pin may be bi-directional.

Managing these complex communication scenarios can be handled through the use of multiple SPP digital control lines, tri-state buffers (TSBs), and analog multiplexers. Due to the serial nature of the incoming command and outgoing data of ASIC 307, in series (intandem), the SPI_DOUT controller line may be used to transmit data to the Cal-Stat pin and the SPI_DIN controller line may receive data from the OUT pin.

In some embodiments, this steering (steering) may be accomplished using a tri-state buffer IC (TSB) at the input to the Cal-Stat pin and an analog multiplexer IC at the output of the OUT pin. SPI_ GENL _chip select lines can be used to manage the steering of these paths. When SPI_ GENL is low, the SPI line is connected to ASIC 307 to support the transmission of all serial commands to ASIC 307 and to receive data from ASIC 307 during a read command. When SPI_ GENL is high, then calibration acknowledge data can be passed back to controller 310 from the Cal-Stat pin via SPI_IO line and wet/dry status data can be passed from the OUT pin to SER_B line. The latter condition may be set by the controller 310, for example. During normal operation, the only path in operation is the path created from the OUT pin to the ser_b line for the transfer of wet/dry state. In this same signal-directed state, the controller 310 samples the SPI-IO input to detect the calibration confirm pulse.

In an "auto-calibration mode" of operation, SPI_ GENL line may be gated low via a signal from basic I/O board 303 and an auto-calibration command may be transmitted over SPI_DOUT to ASIC 307 on the Cal-Stat line. The SPI_ GENL low assertion (assertion) also directs the OUT signal to the SPI_DIN pin, but in this auto-calibration mode of operation, it is ignored by the basic I/O board 303. Once calibration command transmission 824 (FIG. 8) is complete, SPI-GENL line can be deasserted (de-asserted) high to allow basic I/O board 303 to read back the acknowledge pulse through SPI_DIN.

In "manual programming mode," commands may be sent to set the current level, amplifier gain level, and output pin behavior of the light emitters 311. In this manual programming mode, SPI_ GENL can be asserted low, and both the Cal-Stat and OUT signals on ASIC 307 can be routed simultaneously to the SPI_DOUT and SPI_DIN pins, respectively. SPI-GENL remains low for both the transmission of specific manual programming commands and any subsequent (ensuing) responses from ASIC 307.

The ser_a pin is another SPP pin that may be used by the basic I/O board 303 for serial communication. Here, however, it may be used as a digital output. The digital output may allow power to be switched on or off for the entire board. When ser_a is high, the board is powered up. When ser_a is low, the board is powered down.

SPI_CS_FLASH may be used when the microcontroller on the basic I/O board 303 communicates with the ID EEPROM 313. The ID EEPROM 313 may contain board identification information including a board type and a version number. This may be queried by the microcontroller of the basic I/O board 303 at initialization and used to make decisions based on the hardware features supported by a particular version number.

A microchip (e.g., 1K bit SPI serial EEPROM) may be used as the ID EEPROM 313. The ID EEPROM 313 can be preprogrammed with a unique board type ID and board type ID revision (revision). The particular diagnostic analyzer may use the board ID to confirm that the desired hardware configuration has been installed. The memory contents of ID EEPROM 313 can be accessed via a simple SPI interface that is controlled using the spi_clk, spi_din, spi_dout, and spi_cs_flsh signals.

Various measures may be used to minimize noise, crosstalk, and surge immunity problems. For example, +5.3V power may pass through a power inductor prior to accessing LDO 309 to improve power line immunity. Also, all I/O lines may have low pass filters (not shown) in place. Finally, there may be transient voltage suppression (also not shown) applied to each I/O line to mitigate electrostatic discharge events.

In the case of ASIC 307, by using the methods herein, fully integrated, high precision on-board circuitry can distinguish between slightly different levels of reflected light. For this dry/wet application, ASIC 307 may be used to distinguish between light reflected from liquid filled (wet) or air filled (dry) supply line tubing 105.

ASIC 307 (e.g., OPB 9000) may have features including an optical signal amplifier (which may be included in analog front end 318), output comparator 319, and a finite state machine (a state machine operating as controller 310) to control inputs to DAC 320 and receive outputs from photodetector 312 to assist in running auto-calibration method 600C described herein. The OPB9000 may also incorporate other features such as light modulation for ambient light immunization and LED temperature compensation.

As discussed above, ASIC 307 may communicate using a manchester serial communication protocol, which may be a 1-wire protocol that uses a single wire for both clock and data. There are essentially only 3 commands, one of which allows transfer of parameters (parameters) such as READ, WRITE and CALIBRATE. The write may include sequencing nibbles (sequencing nibble) and parameters that may be passed during the write command. The read command has no parameters because it dumps the contents of all registers. The calibration command also has no parameters. An example of an encoded command for a calibration request is shown in fig. 8A.

ASIC 307 may contain four non-volatile registers, BANK1, BANK2, BANK3, and RESERVED (RESERVED). The BANK3 and reserved registers have 11 bits and 7 bits, respectively, that are not recorded. BANK2 has 6 bits, all writable. The format written into this register is 1101-10-bbbbbb. The bit level definition herein is [ sync nibble ] [ detect nibble ] - [ command nibble ] - [ REF0] [ REF1] [ REF2] [ REF3] [ DS ] [ OP ]. The 4 bits of this register are allocated to hold the reference level (REF 0: REF 3). The remaining two bits may be Drain Select (DS) and Output Polarity (OP), which may set the behavior of the discrete output pins. For drain selection, 0 is set for open drain and 1 is set for push-pull operation. For the output polarity, 0 is set for non-inverting (non-inverting) and 1 is set for inverting.

BANK1 has 13 bits, 12 of which are writable. The format written into this register is 1101-01-bbbbbbbbbbbbb. The bit level is defined herein as [ sync nibble ] [ detect nibble ] - [ command nibble ] - [ CA bit ] [ AGC-LSB ] [ AGC-MSB ]

[ LED0] [ LED1] [ LED2] [ LED3] [ LED4] [ LED5] [ LED6] [ LED7] [ LED8] [ LED9]. Bank1 has 10 bits allocated to LED current levels, 2 bits allocated for Automatic Gain Control (AGC) of detected light, and 1 bit allocated for confirmation of calibration success (1=success). Agc=00 sets a gain of 1, agc=01 sets a gain of 4, and agc=10 sets a gain of 8. At a 50% duty cycle setting, the programming communication rate of the write command may be 100kbit/s at maximum. At a 50% duty cycle setting, the programming communication rate of the read command may be 100 kbit/s.+ -. 5kbit/s.

FIG. 8B illustrates a zoomed-out view (lower trace) of an auto-calibration command 823 that may be issued on the Cal-Stat line to initiate auto-calibration method 600C described herein. Fig. 8A shows an enlarged view (trace above) of a calibration request 824 sent from the microcontroller to the cal_stat pin of ASIC 307 during a calibration command 823. Upon receiving this auto-calibration command 823 including a calibration request 824, the pulsed LED driver may ramp its current at a preset v_ref setting in the range of 3mA to 85 mA. The resulting i_led for each v_ref may be recorded in a memory 310M (e.g., EEPROM) of the ASIC 307, as shown in fig. 4B. The auto-calibration method 600C may take less than one second. If the method passes, a13 ms low pulse 825 may be transmitted from the Cal-Stat pin. The CA bit in BANK1 may also be set high.

In more detail, the multi-point self-calibration method 600C is best shown in FIGS. 6C-6F. The method 600C herein operates to achieve calibration with improved wet/dry signal separation. As previously mentioned, this is particularly important because the signal difference between a wet reading and a dry reading is very slight when attempting to detect a clear or somewhat clear liquid, such as in a diagnostic analyzer. To improve the separation of wet signals from dry signals and achieve excellent noise immunity, the self-calibration method 600C generates a multi-point wet calibration curve 404B (e.g., a 16-point wet calibration curve) and a multi-point dry calibration curve 402B (e.g., a 16-point dry calibration curve), such as shown in fig. 4B.

As shown in fig. 6C, method 600C involves turning on circuit 300B at block 601. This may be accomplished by powering the bubble detector assembly 300 via power from the base I/O board 303. Next, a calibration mode is selected in block 603. This may be done automatically, such as running a dry calibration and then a wet calibration, or vice versa. In addition, a calibration signal may be provided from the basic I/O board 303, such as to initiate calibration through the spi_dout pin (fig. 3B).

The method 600C then passes a liquid (e.g., liquid reagent, wash liquid, or the like) or air through the supply line conduit 105 such that the liquid or air is present at the location of the bubble detector 302. In block 605, the passage of liquid or air may optionally be confirmed. For example, the confirmation may be made by monitoring the pump or otherwise monitoring the pressure in the supply line conduit 105.

For each mode (wet calibration mode and dry calibration mode), calibration data is acquired. In blocks 607D and 607W, i_led data is obtained based on the delta voltage input, as shown in fig. 4B. The acquired data may be stored locally and/or may be passed to the basic I/O board 303 and eventually further passed to the computer 316 where the data may be plotted and/or analyzed. A graphical display of the acquired data (v_ref versus i_led) is shown in fig. 4B. The data for the dry and wet curves 402B, 404B may be generated by ramping up the i_led via the voltage input in line 315 to DAC 320 at each v_ref setting until the detected and amplified optical signal from photodetector 311 reaches each v_ref level (fig. 4B). During calibration, the pulsed LED drive signal from DAC 320 ramps up to cause a current to light emitter 311 from about 3mA to about 85 mA. The total ramp (ramp) period may be about 17mS. The v_ref value at which the calibration process is performed may vary from 245mV to 676mV in equally spaced increments, for example, represented by a setting from 0 to 15. However, other numbers of increments and ramp periods may be used.

During calibration mode, the Cal-Stat pin may initially assert high from the spi_dout pin. Calibration is initiated via a calibration command routed from the SPP interface 301 to the Cal-Stat pin, which is facilitated by setting spi_ GENL =0. In this mode, tri-state buffer TSB may drive command data from SPI_DOUT onto the Cal-Stat pin of ASIC 307. Once the command transmission is complete, the tri-state buffer TSB is set to HI-Z mode. This allows for ASIC 307 to drive the Cal-Stat pin. After a successful calibration, which may last approximately 17ms, the Cal-Stat pin will transition to a low state for 13ms. Unsuccessful calibration may occur if the reflective surface 302R is not present or there is insufficient reflected light received by the light detector 312 during calibration. The DAC 320 used may be a 12-bit current control circuit that may dip (sink) the cathode of the LED to ground. The thick arrow labeled 315 from the control logic (state machine) of controller 310 into DAC 320 may represent 10 current control +2 gain control digital lines from controller 310 through to DAC 320 to control the ramp up of current to light emitter 311. The pulsed digital line (thinner line) from controller 310A through to DAC 320 is the gate drive (GATE DRIVE) that modulates the on and off of DAC 320. When the digitally controlled gate drive is in its prescribed operating state (ON-duty) phase, the current sink (current sink) level selected by DAC 320 is issued. In its inactive phase no current sink occurs.

The current to the light emitter 311 (LED) may be pulsed at a duty cycle of 500KHz, 12.5%. In this embodiment, the variability in the intensity of the light emitters 311 (e.g., LEDs) is not controlled by PWM signals as in the embodiment of fig. 2, but rather is independently controlled via opening or closing the channels of the driver to permit or limit current flow to the light emitters 311.

The remaining unscattered light from the light emitter 311 is received by the light detector 312 as it passes through the supply line pipe 105 a first time, is reflected off of the reflective surface 320R, and passes through the supply line pipe 105 a second time, the light detector 312 may be any suitable photodiode. Increasing this voltage may provide an increase in current to the light emitter 311 and thus cause an increase in voltage from the light detector 312 for any given v_ref applied.

Fig. 6D illustrates a flow chart of a method of generating a dry or wet calibration curve for calibration of the second bubble detector assembly 300. In this method, calibration is performed at each reference voltage value (v_ref) available for use. In this way, a multi-point approach is provided that scans across available reference voltage inputs and feeds into the internal comparator 319 of the optical bubble detector assembly 300 according to an embodiment. In particular, fig. 6D illustrates one method of how the i_led value may be obtained in blocks 607D and 607W.

In block 608, at the beginning of the scan, the value of V_Ref is set to zero. In block 610, calibration is performed by scanning v_ref from a minimum value v_ref_min=0 to a maximum value v_ref_max. The value of v_ref may be an integer value. V_ref_max may be an integer such as 15. Thus in this example, v_ref is scanned by DAC 320 and incremented from 0 to 15 in increments of one, with each number being proportional to the voltage output in fig. 3B. As v_ref is scanned, the i_led values generated from the current received from the photodetector 312 in the output line 317, which are necessary to match each v_ref value, are recorded in block 612, as determined by the comparator 319. For example, the resulting I_LED value corresponding to each V_Ref delta may be stored in local memory. Alternatively or additionally, data may be sent to the basic I/O board 303 and computer 316.

Analog front end 318 may receive an output in line 317 from photodetector 312 corresponding to each increment v_ref provided as an input to comparator 319. The analog front end 318 may be bandpass filtered to phase lock the photodetector circuitry to the LED drive circuitry. The output signal in 317 is thus received only during the time interval in which the gate drive signal of DAC 320 is enabled. In this way, any constant optical signal (like ambient light) or other noise artifacts (e.g., 60Hz noise) that occur at other frequencies can be ignored. The analog front end 318 may also include suitable amplification.

When v_ref is equal to v_ref_max in block 614, then incremental stopping for the dry and wet calibration modes may begin by repeating the steps in fig. 6D for the wet calibration mode. In other embodiments, wet calibration may occur before dry calibration.

Referring again to FIG. 6C, once the data scan in FIG. 6D is completed, the self-calibration method 600C may optionally implement a confirmation in block 609 to ensure that sufficient data has been generated for both wet and dry calibrated individuals. This confirmation may be accomplished by the controller 310 evaluating that there is a desired number (e.g., 15) of successful calibrations in the row, one for each v_ref input. Next, in block 613, the self-calibration method 600C may perform an analysis of the data points that make up the wet and dry calibration curves 404B, 402B, which are obtained and stored from the method implementing FIG. 6D, to obtain the Final values of I_LED_Final and V_Ref_Final. An optional data check may be performed in block 615 as a precursor to the analysis (pre) or concurrently with the analysis to see if the received data will be sufficient for the analysis. For example, the data may be checked to see that the received maximum i_led has met at least a minimum pre-established current level, such as 10mA, or to evaluate the difference between the v_ref value at the intersection with the i_led line 409 and the pre-established voltage delta value (Δv). In particular, at i_led_final409, the pre-established voltage delta value (Δv) should be a 3.50 or more complete v_ref division between the wet calibration curve 404B and the dry calibration curve 402B. Additionally or alternatively, the I_DRY/I_WET current ratio (C1/C2) at V_Ref_Final on line 407 should be C1/C1. Gtoreq.1.15.

As shown in block 621, the analysis of method 600C in block 613 ultimately results in the determination of i_led_final, which is a current value that may be stored in EEPROM 310M. Briefly, the analysis in block 613 finds the final calibration setting 409, i.e., the current setting, which results in an i_led current to the light emitter 311 that allows proper operation within the active area of both wet (404B) and dry (402B) calibration data curves.

To assist in understanding how the final calibration settings 409 may be selected in this embodiment, reference is made to fig. 4B and 6E. The calibrated I_LED_Final setting method 613I shown in FIG. 6E includes, in block 620, finding I_LED_Max as the maximum current value on the wet curve 404B. In block 622, method 613I includes finding i_led_min as the minimum current value on the dry curve 402B. In block 624, the i_led_final value, i.e., the Final calibration setting, is determined. This i_led_final value is used for forward wet/dry detection as shown in block 621 (fig. 6C). For example, the I_LED_Final value may be calculated as (I_LED_Max+I_LED_Min)/2. The i_led_final value may be rounded to the nearest integer (whole number) corresponding to the v_ref value that DAC320 is capable of outputting.

According to method 600C, the analysis of v_dry and v_wet data in block 613 may further determine a Final reference value v_ref_final, which is a comparator threshold that is advanced when determining a WET or DRY determination of supply line pipe 105. In one embodiment, a threshold determination method 613T for determining v_ref_final is shown in fig. 6F.

Knowing the i_led_final from the previous flow chart of fig. 6E, v_ref_final can now be determined. I_led_final may be rounded to the nearest value. According to method 613T, wetV _ REFINTERCEPT on fig. 4B is calculated (point E) in block 626 and DryV _ REFINTERCEPT is calculated (point F) in block 628. This involves identifying wet (straddle) points (a and B) and dry points C and D. The wet crossover points, referred to herein as WETHIGHEDGE (point a) and WetLowEdge (point B), straddle either side of WetV _ REFINTERCEPT (point E), as shown in fig. 4B. Similarly, dry cross points, referred to herein as DRYHIGHEDGE (point C) and DryLowEdge (point D), straddle either side of DryV _ REFINTERCEPT (point F), as shown in fig. 4B. The cross points may be points directly above and directly below the intersection points E and F.

In block 630, v_ref_final is determined. V_ref_final may be determined by determining WetV _ REFINTERCEPT and DryV _ REFINTERCEPT in any order as follows:

as shown in block 626, wetV _ REFINTERCEPT (point E) is calculated using the following calculations and definitions:

WETHIGHEDGE = wet calibration current value closest to and greater than or equal to the Final i_led_final at point a.

WetHighV _ref=v_ref value corresponding to WETHIGHEDGE current at point a.

WetLowEdge = wet calibration current value of i_led_final closest and less than or equal to at point B.

WetLowV _ref=v_ref value corresponding to WetLowEdge current at point B.

WETYINTERCEPT = Y intercept (interseptic) of a straight line passing through points (WetHighV _ref, WETHIGHEDGE) and (WetLowV _ref, wetLowEdge), i.e. through points a and B.

WetSlope = slope (slope) of the line passing through points (WetHighV _ref, WETHIGHEDGE) and (WetLowV _ref, wetLowEdge), i.e. slope of the line passing through points a and B.

WetV _ REFINTERCEPT =i_led_final current value and the point at which the wet calibration curve 404B intersects.

WetSlope＝(WetHighEdge–WetLowEdge)/(WetHighV_Ref–WetLowV_Ref)＝WetHighEdge–WetLowEdge/1＝WetHighEdge–WetLowEdge( Note that Δv_ref is always equal to 1

WetYIntercept=WetLowEdge-(WetLowV_Ref*(WetHighEdge-WetLowEdge))

WetV _ REFINTERCEPT (Point E) = (I_LED_final-WETYINTERCEPT)/(WETHIGHEDGE-WetLowEdge)

If the I_LED_Final current intersects the wet calibration curve 404B directly at a calibration point (e.g., one of points 1-15), wetV _ REFINTERCEPT is equal to the V_Ref value for that calibration point.

As shown in block 628, dryV _ REFINTERCEPT (point F) is calculated using the following calculations and definitions:

DRYHIGHEDGE = dry calibration current value of i_led_final current closest to and greater than or equal to point C.

DryHighV _ref=v_ref value corresponding to DRYHIGHEDGE current at point C.

DryLowEdge = dry calibration current value of i_led_final current closest to and less than or equal to the D point.

DryLowvRef = v_ref value corresponding to DryLowEdge current at point D.

DRYYINTERCEPT = Y intercept of a straight line that would pass through points (WetHighV _ref, WETHIGHEDGE) and (WetLowV _ref, wetLowEdge), i.e. through points C and D.

DrySlope = slope of the line passing through points (DryHighV _ref, DRYHIGHEDGE) and (DryLowV _ref, dryLowEdge), i.e. slope of the line passing through points C and D.

DryV _ REFINTERCEPT =v_ref point where the i_led_final current value intersects the wet calibration curve 404B.

Wet Slope＝(DryHighEdge–DryLowEdge)/(DryHighV_Ref–DryLowV_Ref)＝(DryHighEdge–DryLowEdge)/1＝(DryHighEdge–DryLowEdge).( Note that avvref is always equal to 1

DryYIntercept=DryLowV_Ref*(DryHighEdge–DryLowEdge)

DryV_RefIntercept(F)=(I_LED_Final–DryYIntercept)/(DryHighEdge–DryLowEdge)。

If the I_LED_Final current 409 intersects the dry calibration curve 402B at a calibration point, dryV _ REFINTERCEPT is equal to the V_Ref value for that calibration point.

In block 630, the method 613T may optionally perform a pass/fail deltav_ref test. This alternative test may analyze the v_ref values of points E and F. The test may involve calculating a deltav_ref value, wherein:

DeltaV_Ref=WetV_RefIntercept-DryV_RefIntercept。

The pass/fail criteria may be a deltav_ref value that is 3.50 or more complete v_ref division (point E-point F) between the intersection of the wet calibration curve 404B and the dry calibration curve 402B at i_led_final 409.

In some embodiments, a Current Ratio (CR) test may also optionally be performed in block 632, wherein:

c1 Dry calibration current value on dry curve 402B corresponding to v_ref_final, and

C2 Wet calibration current values on wet curve 404B corresponding to v_ref_final.

The current ratio is defined as cr=c1/C2. For example, the pass/fail criteria may be that CR at V_REF_Final must be ≡1.5.

After determining WetV _ REFINTERCEPT and DryV _ REFINTERCEPT in blocks 626 and 628, the v_ref_final value may be calculated in block 634 as follows:

V_RefFinal=<WetV_RefIntercept+DryV_RefIntercept)/2。

The v_ref_final value may be rounded to the nearest v_ref integer. The v_ref_final value may be used as the forward comparator threshold V _TH. The comparator threshold V _TH may be used as a demarcation (trigger) point between the wet and dry determinations. As should be appreciated, the resulting value of v_ref_final is the reference voltage setting that achieves the highest level of signal separation between wet and dry states.

These two Final parameters (i_led_final and v_ref_final) may be written to and stored in EEPROM 310M. This calibration method 600C of fig. 6C allows finding excellent trip (trip) points for signaling the dry and wet status in forward use.

Referring again to fig. 9A-9F, the ASIC307 of the bubble detector assembly 300 can include a support 930, such as a cylinder (e.g., a metal cylinder) that can be coupled to a printed circuit board 932, the support 930 operative to contact and position the supply line conduit 105 at a defined distance away from the light emitter 311 and the light detector 312 (fig. 9E). For example, the defined distance between the light emitter 311 (or light detector 312) and the nearest portion of the supply line conduit 105 may be about 2.09mm. However, other suitable distances may be used. On the other side of the supply line duct 105, a reflective surface 302R is provided. The reflective surface 302R may be formed of any suitable reflective material, such as a reflective film 934. The reflective film 934 may be a 3M ^TMSCOTCHLITE^TM reflective graphic film 680-10 or the like. The reflective film 934 may be attached to a surface, such as a flat surface 935 of the support member 933. For example, the reflective film 934 may be wrapped (wrap) around and fastened to the support member 933. The support member 933 may be a rigid block, such as, for example, an aluminum block.

The support member 933 with reflective surface 302R can be coupled to the backing member 936, such as by using fasteners 937 as shown in fig. 9B and 9D or another suitable attachment mechanism. The backing member 936 may include a groove 938 along its length, the groove 938 configured to receive the supply line conduit 105 therein. When backing member 933 is assembled to printed circuit board 932, as shown in fig. 9A, the bottom of groove 938 is in contact with supply line conduit 105 along its length, as is support 930, and thus the position of supply line conduit 105 relative to both light emitter 311 and light detector 312, and further relative to reflective surface 302R, can be precisely controlled. The reflective surface 302R may be configured to be approximately 2.5mm away from the nearest portion of the supply line conduit 105. However, other suitable distances may be used.

As shown, the supply line conduit 105 may be further secured by a bracket 947 coupled to the backing member 936. The attachment fasteners 949 may be part of the bubble detector assembly 300 and serve to secure the bubble detector assembly 300 to a structure. For example, in some embodiments, the bubble detector assembly 300 may be mounted to a frame of a diagnostic analyzer, the probe 945 itself, a structure (not shown) attached to the probe 945, a portion of a robot (not shown) that operates to move the probe 945, or a cleaning station.

In another embodiment, a computer program product is provided. The computer program product includes a computer-readable non-transitory medium having computer program code configured to receive a first plurality of outputs, each of the first plurality of outputs representing an amount of light detected through a supply line pipe having no liquid therein for a respective plurality of inputs to a light emitter, receive a second plurality of outputs, each of the second plurality of outputs representing an amount of light detected through a supply line pipe having liquid therein for a respective plurality of inputs, and set a threshold based on a selected one of the first plurality of outputs and the second plurality of outputs.

In one embodiment, the computer program code of the computer program product may be configured to select one of a respective plurality of inputs for which a maximum difference occurs between a respective pair of the first and second plurality of outputs, and determine the threshold based on the respective pair of the first and second plurality of outputs for which the maximum difference occurs. In another embodiment, the computer program code of the computer program product may be configured to select the operation input (i_led_final) based on a minimum i_led value (i_led_min) and a maximum i_led value (i_led_max). The threshold may be located halfway between the intersection of the i_led_final and the wet and dry i_led to v_ref curves.

Those skilled in the art will readily appreciate that the disclosure described herein has broad utility and application is a diagnostic analyzer. Adaptations of many embodiments and disclosed embodiments, as well as many variations, modifications, and equivalent arrangements, other than those described herein, will be apparent from or reasonably suggested by the present disclosure and the detailed description herein, without departing from the substance or scope of the present disclosure.

For example, although described in connection with a particular liquid bubble detector, one or more embodiments of the present disclosure may be used with other types of liquid bubble detectors. Thus, although the present disclosure has been described in detail herein with respect to particular embodiments, it should be understood that the present disclosure is only illustrative, presents examples of the present disclosure, and is made solely for the purpose of providing a full and enabling disclosure. The disclosure is not intended to limit the invention to the particular apparatus, devices, assemblies, systems or methods disclosed herein, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.

Claims

1. An optical bubble detector assembly, comprising:

The controller is configured as:

operating a light emitter to project light into a supply line conduit of the optical bubble detector at a plurality of light intensities corresponding to the plurality of inputs;

receiving a first plurality of outputs from a light detector of the optical bubble detector, the first plurality of outputs corresponding respectively to the plurality of inputs, each of the first plurality of outputs representing an amount of light detected through the supply line conduit without liquid therein;

receiving a second plurality of outputs from the light detector, the second plurality of outputs corresponding respectively to the plurality of inputs, each of the second plurality of outputs representing an amount of light detected through the supply line conduit having liquid therein; and

Based on the selected output from the first and second pluralities of outputs, a particular one of the plurality of inputs is selected as a final calibration setting.

2 . The assembly of claim 1 , wherein the controller is further configured to determine a threshold based on a selected output of the first and second pluralities of outputs.

3 . The assembly of claim 1 , wherein the controller is configured to operate the light emitter at the final calibration setting when detecting whether the supply line conduit contains the liquid or air.

4. The assembly of claim 1 , wherein the controller is further configured to:

selecting a maximum current based on the first plurality of outputs;

selecting a minimum current based on the second plurality of outputs; and

The final calibration setting is determined to be between the maximum current and the minimum current.

5 . The assembly of claim 4 , wherein the final calibration setting comprises a value approximately midway between the maximum current and the minimum current.

6. The assembly of claim 1 , wherein the controller is configured to:

The threshold value is selected as the voltage value at which a maximum voltage difference occurs between corresponding pairs of the first and second pluralities of voltages.

7. The assembly of claim 6, wherein the threshold comprises an operating voltage midway between respective pairs of the first and second pluralities of voltages where the maximum voltage difference occurs.

8. The assembly of claim 1, wherein the controller is configured to calculate a voltage difference between each corresponding pair of the first and second pluralities of outputs for each of a plurality of duty cycle periods.

9. The assembly of claim 1, further comprising an operational amplifier coupled to receive a pulse width modulation input from the controller and configured to provide a current input to the optical emitter in response thereto.

10. The assembly of claim 1, wherein the controller is configured to store a plurality of stored values representing the first and second pluralities of outputs in a non-volatile memory.

11. The assembly of claim 1, wherein the controller is configured to operate the light emitting device at the final calibration setting and determine whether the supply line conduit has liquid or air based on a threshold value.

12. The assembly of claim 1, wherein the supply line conduit is held between a backing member and a support to space the light emitter and light detector from the supply line conduit.

13. The assembly of claim 12, wherein the supply line conduit is retained in a groove formed in the backing member.

14. A method for calibrating an optical bubble detector, comprising:

receiving a first plurality of outputs, each of the first plurality of outputs representing an amount of light detected through a supply line conduit without liquid therein, the first plurality of outputs respectively corresponding to a plurality of inputs to a light emitter;

receiving a second plurality of outputs, each of the second plurality of outputs representing an amount of light detected through the supply line conduit having liquid therein, the second plurality of outputs respectively corresponding to the plurality of inputs to the light emitter; and

15. The method of claim 14, further comprising setting a threshold based on a selected output of the first and second pluralities of outputs.

16. The method of claim 15, wherein the controller is operable to:

selecting a minimum current based on the first plurality of outputs;

selecting a maximum current based on the second plurality of outputs; and

The final calibration setting between the maximum current and the minimum current is determined.

17. The method of claim 16, wherein the final calibration setting is midway between the maximum current and the minimum current.

18. The method of claim 14, further comprising setting the optical transmitter to operate at a final calibration setting corresponding to a position where a maximum voltage difference occurs between corresponding pairs of the first and second pluralities of outputs.

19. The method of claim 14, further comprising setting a threshold based on the corresponding pairs of the first plurality of outputs and the second plurality of outputs.

20. The method of claim 14, further comprising calculating, with a controller, a difference between each corresponding pair of the first plurality of outputs and the second plurality of outputs for each corresponding plurality of inputs.

21. The method of claim 14, wherein the plurality of inputs are % duty cycle settings ranging from 10% to 40% of maximum output.

22. The method of claim 14, wherein the plurality of inputs comprises at least 10 different inputs.

23. The method of claim 14, further comprising operating the light emitter in the final calibration setting to detect the supply line conduit with no liquid therein or with liquid therein.

24. The method of claim 14, further comprising storing in a non-volatile memory a value representing a threshold value, the threshold value corresponding to an operational output between the first plurality of outputs and the second plurality of outputs.

25. A computer program product comprising:

A computer readable non-transitory medium having a computer program code configured to:

receiving a first plurality of outputs, each of the first plurality of outputs representing an amount of light detected through a supply line conduit without liquid therein for a corresponding plurality of inputs to the light emitters;

receiving a second plurality of outputs, each of the second plurality of outputs representing an amount of light detected through the supply line conduit having liquid therein for a corresponding plurality of inputs; and

Final calibration settings are set based on selected outputs of the first plurality of outputs and the second plurality of outputs.

26. The computer program product of claim 25, wherein the computer program code is configured to:

selecting one of said corresponding plurality of inputs for which a maximum difference occurs between corresponding pairs of said first and second pluralities of outputs; and

The final calibration settings are determined based on the corresponding pairs of the first and second pluralities of outputs where the maximum differences occur.

27. The computer program product of claim 25, wherein the computer program code is configured to:

determining a minimum I_LED based on the first plurality of outputs;

determining a maximum I_LED based on the second plurality of outputs; and

The final calibration setting is selected between the maximum I_LED and the minimum I_LED.

28. The computer program product of claim 27, wherein a threshold is determined based on an intersection of the final calibration setting with a wet curve and a dry curve.