RU2696068C2 - Intelligent converter - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to electronic engineering, particularly, to manufacturing of tensoresistor pressure converters. Unit is introduced into the intelligent transducer that is responsible for dynamically adjusting the settings based on the pressure measured by the transducer.

EFFECT: technical result of this solution consists in improvement of degree of action on external controlled device due to comparison of rate of change of pressure at approach to specified boundary values by pressure.

1 cl, 2 dwg

Description

The invention relates to electronic equipment, in particular to a manufacturing technology of strain gauge pressure transducers.

Strain gages pressure transducers relate to products using thin-film strain gages as sensitive elements. The converter uses an indicator to display information about the measured value. This set of transducer and indicator is usually defined as a sensor (pressure sensors, temperature sensors and others). The signal of the sensor element of the converter most often requires appropriate processing and analysis. A modern direction in their development is the endowment of converters with some functions that allow us to talk about a certain degree of intellectualization. The actions performed by the devices built into the converter include self-monitoring, self-diagnosis, taking into account the non-linearity and temperature dependences of the parameters of the sensitive element and their corresponding correction. The named characteristics of the converter should be attributed to the built-in intelligent internal functions. If the data from the converter is used to control external devices, then we can talk about the intelligent external functions of the converter. To perform the indicated intellectual actions, microcomputers are used (another name is microcontrollers, microprocessors, see, for example, US Pat. No. 4,644,482, G01N 7/00, 12/21/1984). For their installation, the necessary design improvements were made in a number of converters. At the same time, there are some variations in the arrangement of microcircuits with controllers relative to the sensitive element: next to the sensitive element (see, for example, US Pat. No. 6140144, H01L 21 / 0014.04.1997), on the cover of the sensor oriented to measuring absolute pressure (US Pat. No. 2564378, G01L 9/04, 05/22/2014), along the axis perpendicular to the sensitive element (US Pat. No. 9046436, G01L 7/00, G01L 9/00, G01L 19/14, 03/27/2012) and on the sensitive element (US Pat. No. 9772242, G01L 9/00, G01L 9/00, G01L 19/14, dated 12/14/2014).

In the first case, wires are used to connect the microcircuit to the sensitive piezoresistive element. The output from the chip for attaching an external device is not disclosed. The indicated location of the microcircuit increases the geometric dimensions of the converter.

In the second case, for the location of the microcircuit, a cover of a sensitive element intended for measuring absolute pressure is used. Contact pads are formed directly on it, and conductors are welded to them for output to the contact pads of the converter housing. The location of a working microcircuit on a sensitive element can lead to a change in the temperature of the element and, accordingly, make a certain contribution to the temperature error. In addition, the size of the sensor must correspond to the size of the installed microcircuit.

When the processing of the output signal of the microcircuit was perpendicular to the sensitive element, it was necessary to implement the original node for transmitting the signal from the sensitive element to the microcircuit. Namely, a ring with contact pads located flush with the sensitive element is applied to the tip of the sensitive element to connect the contact pads of the sensitive element with conductors with the contact pads of the installed ring. In the recesses of the indicated ring, the mating board with the microcircuit is installed as the counterpart. In this case, the contact pads available on the mating parts come into contact with the contact pads of the ring. On the opposite side, the terminals signaling the processed signal are installed on the metallized terminals.

The design has increased dimensions in length, but this is offset by the ease of assembly of the device.

Foreign analogues are known in which smart pressure transmitters are used, containing the functions of its control and diagnostics. So, the company United Electric Controls produces UEONESERIES devices with self-testing and diagnostics, programmable set points, memory for

technological parameters. The built-in microprocessor provides a measurement accuracy of 0.5% and reproducibility of the results of 0.1%, while it controls the operation of the relay, increasing its reliability. (www.cis-automation.ru, http://www.cis-automation.ru/Catalog/RUSSIAN/8W-R.pdf, found on the Internet on 10/31/2017).

If the setpoint points are programmed in the above device that does not take into account the real response speeds of the controlled pressure switches of the devices, then in the method of controlling the valve of the control valve, a setpoint value of 4 to 20 mA or a control signal generated by the process controller is used (RF patent No. 2424449, F15B 9/03, from 01/17/2006). In this case, the signal is first fed to the “advance delay” filter circuit, and then to the valve control circuit. That is, here the formation of the settings is performed in the external control circuit, where the valve response errors from the setpoint are also taken into account.

A technical solution is known, taken as the one closest to the proposed converter, in which the signal processing chip is mounted directly on the diaphragm of the sensing element (US Pat. No. 5629486, G01L 9/06, dated January 12, 1996). In the node for outputting the signal from the sensitive element by the gold tracks, the piezoresistors formed on silicon are connected to the signal processing microcircuit. The same tracks go to the terminals on the connection terminals mounted on the cylindrical ring. Despite the use of gold contacts, a heat flux can come from the microcircuit, especially if it is powerful enough due to the presence of various functions. The heat flux distorts the resistance of resistors located on opposite sides of the microcircuit. It is difficult to take into account the corrective function of the microcircuit, which affects the measurement error. In addition, the temperature of the medium can be high, which can lead to additional heating of the microcircuit and affect the measured parameter.

The technical task of the proposed technical solution is to improve the design of the Converter, improving its characteristics in terms of reliability, performance and stability, as well as expanding its functionality.

The technical result of this technical solution is the design of the converter with additional intelligent functions. Moreover, in the proposed design, the level of impact on the external controlled device is increased, which is achieved by introducing variable settings and is implemented by comparing the rate of change of pressure when approaching the specified boundary pressure values.

This problem is solved by the fact that in the proposed smart converter comprising a housing with a sensing element, a signal output unit from the sensing element to the signal processing chip, the latter uses a ceramic ring with pads and terminals, with a covered part of its area with another ceramic ring, so that the pads are attached to the sensing element, and the rings are mounted on a metal ring in the housing, so that the edge of the indicated metal ring is close to oskosti of the sensitive element, and a ceramic board for attaching the microcircuit is installed through a metal ring placed on the second ceramic ring, while in the microcircuit there is a unit for outputting the setting parameters for controlling an external device, which allows setting parameters to be varied by changing the rate of change of pressure measured by the sensitive element.

Placing the microcircuit on the integrated board reduces the effect of uncompensated thermal fluxes and voltages, since it is removed from the resistors of the sensitive element and is accessible for connection by welding electrical connections.

The location of the chip on the integrated board allows you to compactly place it in the case, without changing the size and configuration. The design allows you to thermally isolate the sensitive element and the microcircuit by reducing the heat flux from the working medium through ceramic rings and the board. At the same time, the influence of rapid temperature changes and high-frequency mechanical vibrations transmitted from the flow of the working medium is reduced.

The separation of the sensitive element and the microcircuit does not cause additional stresses both in the manufacture and assembly of the sensor, and during its operation in a wide range of temperatures and measured pressures.

The introduction of the node responsible for issuing the installation parameters allows the proposed design to be used to control external devices with the possibility of optimal adjustment to their characteristics.

The proposed solution is illustrated by the drawings.

In FIG. 1 is a view of an intelligent pressure transducer showing a transducer with pads of an output assembly and a microcircuit.

In FIG. Figure 2 shows the algorithm for using the smart converter as a relay to control an external device.

In the proposed design, as an example, describe a sensitive element made in the form of a "silicon on sapphire" structure with strain gauges connected to each other in the Winston bridge, and a microcircuit whose functions allow us to talk about the intellectual properties of the converter, and are indicated in the overview part of this description.

As shown in FIG. 1, the proposed smart converter comprises a sealed housing 1 with a pressure sensor 2 installed therein. To output the signal from the bridge, the elements of the node for outputting the signal from the sensing element are used; the landing metal ring 3, the first ceramic ring 4, the second ceramic ring 5, on which the intermediate metal ring 6 is superimposed on top.

In turn, a ceramic board 9 is installed on the intermediate ring 6 for mounting the microcircuit 10. On the first ring 4, pins 8 and pads 7 with wiring are mounted. The pads 7 are used to connect to the pads on the sensing element (not shown) by welding the conductors, for example, of thin aluminum wire. Flat electrical connections are made using microelectronic technologies, for example, electrochemical methods or spraying. The housing 1 has a channel (not shown) for supplying a measured pressure of the medium, which allows the use of a transducer for measuring the relative pressure of the medium.

The mechanical connection of the sensitive element and the metal membrane is made by high-temperature soldering in vacuum solder type PSR. Typically, a chip has a normalized or digital output. In this case, the microcircuit contains a node that allows you to display the installation parameters (settings) for use in controlling external pneumatic devices, for example, valves, flaps or other devices. The presence of a microcontroller allows you to set and manage the settings depending on the individual parameters of external devices. The response speeds of electrical and pneumatic circuits of external devices can differ significantly from each other. Only if the pressure sensor is integrated in the control device together with the valve, we can talk about the constant settings. And even in the process of operation, wear and tear of equipment will require their adjustment.

Intelligent Converter operates as follows.

The measured pressure of the working medium enters under the sensitive element 2 located in the sealed housing 1 of the Converter, changes the shape of the sensitive element and the resistance of the strain gauges. In chip 10, the analog signal from the bridge resistors is converted into a normalized or digital signal and fed further to the output of the converter. The setting parameters node is analyzed by the program in accordance with the algorithm shown in FIG. 2. The analysis allows you to determine whether the contacts are used to supply the settings, or the converter has only a normalized or digital signal at the output. In the presented diagram, this part of the chip's functions is presented as the presence of two operating modes. In the first case (mode 1), the converter has only data on the measured pressure value at the output. In the case of using the converter using the relay function (mode 2), a comparison of the rate of increase or decrease of pressure is performed depending on the set settings. If the measured parameters differ from the required pressure maintenance limits, the microcircuit corrects the settings by shifting or pushing their values. Thereby, the optimum use of the capabilities of controlled external devices is achieved. The smart converter adapts to the capabilities of the external pressure control circuit and changes the settings due to possible deviations of the characteristics of the external controlled environment during operation.

The proposed improvements were used in the design documentation for the produced pressure transducer, which made it possible to increase its technical level and functionality.

The developed manufacturing technology of the improved design of the smart converter allows to achieve the stability of its performance, to maintain the miniature design, to provide protection from external factors. In addition, its functionality for controlling external devices with the required characteristics of the output (input) signal for various pressure values is expanded.

Claims (1)

An intelligent pressure transducer comprising a housing with a sensing element, a node for outputting a signal from the sensing element to a signal processing chip, characterized in that a ceramic ring with contact pads and terminals, with a covered part of its area with another ceramic ring, is used in the output node of the output signal, so that pads are attached to the sensitive element, while the rings are mounted on a metal ring in the housing in the plane of the sensitive element, and a ceramic board for the microcircuit connections are installed through a metal ring placed on the second ceramic ring, while the microcircuit provides a node for outputting the settings for controlling an external device, which allows you to vary the settings for changing the rate of change of pressure measured by the sensitive element.

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