CN108680549B - A Measurement and Control System of Dispersive Atomic Fluorescence Spectrometer Based on DMD - Google Patents

Abstract

The invention relates to a DMD-based measurement and control system of a dispersion type atomic fluorescence spectrometer, which comprises a mother board, a lamp panel, a dispersion acquisition control panel, a non-dispersion acquisition control panel and a reference channel control panel, wherein the number of the PCB boards is 5; the lamp panel, the dispersion acquisition control panel, the non-dispersion acquisition control panel and the reference channel control panel are in hard connection with the motherboard through a socket, and the dispersion acquisition control panel, the non-dispersion acquisition control panel and the reference channel control panel are respectively wrapped by shielding boxes; the external interfaces on each shielding box comprise a PMT power supply interface and a PMT signal acquisition interface. The invention has high integration level and good stability, and can coordinate with the control of the DMD control panel to ensure that the light source, the dispersion detection system, the non-dispersion detection system and the light source spectral line correction system of the spectrometer work in coordination and order.

Description

A Measurement and Control System of Dispersive Atomic Fluorescence Spectrometer Based on DMD

Technical field:

The invention relates to the technical field of atomic fluorescence spectrometry, in particular to a measurement and control system of a novel dispersion type atomic fluorescence spectrometer based on DMD.

Background technique:

Atomic fluorescence spectrometry is a detection method that collects, processes, and analyzes the fluorescence spectrum generated by the excitation of the ground state atoms of the target element by specific frequency radiation, and finally obtains the qualitative and quantitative information of the element. The atomic fluorescence spectrometer is designed and produced based on this method. In the existing atomic fluorescence technology, the method of hydride generation is used to make the target element react to generate the corresponding hydride, which is separated from the high-temperature element that is difficult to atomize and easy to produce metal oxide, so as to eliminate the interference to the test of the target element. But the elements that can be separated by hydride are only 12 kinds of inorganic heavy metal elements such as arsenic, antimony, bismuth and mercury. Atomic fluorescence spectrometers are currently widely used in environmental monitoring, food hygiene, water quality monitoring and other fields.

The existing AFS (atomic fluorescence spectrometer) is a non-dispersive AFS, which measures the total atomic fluorescence of the target element, and has the advantages of detecting a wide range of wavelengths, high flexibility, fast speed, high sensitivity, low background, and multi-channel simultaneous detection. However, due to the problem of spectral interference in the non-dispersive AFS optical system, some elements cannot be accurately measured. In order to solve the above problems, AFS based on DMD is further provided.

DMD is a digital micro-mirror device developed and designed by Texas Instruments. It is a micro-motor system and acts as a reflective light modulator, which can realize rapid selection of space light. At present, it is the optical switch with the highest precision and the fastest speed. The digital optical processing technology with DMD as the core device has been widely used in the fields of optical projection, optical measurement, optical fiber network and spectral analysis. It has good application development and wide market. prospect.

The new DMD-based AFS currently developed aims to achieve full-spectrum, multi-channel and multi-information rapid detection of atomic fluorescence by measuring the spectral lines of different elements through DMD technology. The final result will be detected according to the wavelength position corresponding to the DMD. The fluorescence intensity is plotted, and the results are processed and analyzed. Among them, the DMD control board is controlled by FPJA chip containing XILINX's model xcv5vlx50-ff1153, and the communication method with the host computer is network port communication. The host computer software XXX sets various parameters and displays the spectrum. For the hardware circuit part of the lower computer, the DMD control board is used as the core. Therefore, based on the above, it is necessary to develop a measurement and control system, develop the control interface and system synchronization control technology of the newly developed components of the instrument system and existing components, and realize the measurement and control system with the DMD control board. The control of efficient, coordinated, fast and orderly work.

Invention content:

The technical problem to be solved by the present invention is to provide a measurement and control system of a DMD-based dispersive atomic fluorescence spectrometer. The dispersion detection system and the light source spectral line correction system work in a coordinated and orderly manner.

In order to solve the above-mentioned technical problems, the measurement and control system of the DMD-based dispersive atomic fluorescence spectrometer of the present invention includes a total of 5 PCB boards, a motherboard, a lamp board, a dispersion acquisition control board, a non-dispersive acquisition control board and a reference channel control board; The light board, the dispersion acquisition control board, the non-dispersive acquisition control board and the reference channel control board are hard-connected to the motherboard through sockets, and the dispersion acquisition control board, the non-dispersive acquisition control board and the reference channel control board are respectively wrapped by shielding boxes; The external interface on each shielding box includes a PMT power supply interface and a PMT signal acquisition interface.

The PMT signal acquisition interface adopts a BNC plug.

The motherboard is fixed with 24V power supply interface, 24V to ±12V power conversion module, 24V to 5V power conversion module, IO interface, LVDS bus, dual street light identification interface, CAN bus; external power supply 24V DC voltage through the 24V power supply interface Power supply for the entire measurement and control system; 24V DC voltage is converted into ±12V, 5V DC voltage by 24V to ±12V power conversion module and 24V to 5V power conversion module respectively, and provides the light board, dispersion acquisition control board, non-dispersion acquisition control board and parameters. Bidao control board; the motherboard communicates with the DMD control board through LVDS bus, IO interface and CAN bus.

The lamp board is fixed with an HCL power supply high-voltage module, a two-way HCL drive circuit module, an STM32 processing module, a DA module, an HCL lamp identification module, a channel A HCL power supply interface and a channel B HCL power supply interface; the lamp sockets of the two channels of HCL output binary The double-lane lamp model data is transmitted to the HCL lamp identification module through the double-lane lamp identification interface. The HCL lamp identification module organizes the double-lane lamp model data into two binary digital signals representing the lamp model and inputs them to the STM32 processing module; the STM32 processing module converts the binary The digital signal operation is converted into a hexadecimal reply signal, which is sent to the DMD control board through the CAN bus; the STM32 processing module receives the two-way HCL lamp current that needs to be set transmitted by the DMD control board through the CAN bus, and generates two-way HCL driver through calculation. The digital signal enters the DA module, and the DA module converts it to generate two-way HCL driving voltage to the two-way HCL driving circuit module to generate the expected HCL lamp current; the lighting sequence output by the DMD control board is sent to the two-way HCL driver through the IO interface Circuit module; 24V DC voltage is input to the HCL power supply high-voltage module to generate 300V voltage and divide it into two channels. At the same time, the two-way HCL drive circuit module combines the HCL lamp current and 300V voltage and connects it through the HCL power supply interface of channel A and the HCL power supply interface of channel B. Supply power to two HCL lamps.

The dispersion acquisition control board includes a signal adjustment circuit module, an AD module, a negative high voltage module, and a DA module; the DMD control board sends out an integral discharge signal, a background signal, a gain signal and a phase sensitive signal and transmits it to the signal adjustment circuit module through the IO interface; The weak current signal of the spectrometer dispersion detection system PMT collected through the PMT signal acquisition interface is sent to the signal adjustment circuit module. Under the action of the sensitive signal, it is amplified by gain, deducted from the background signal, converted into a square wave, and finally a DC voltage is obtained under the action of the integral discharge signal; the DC voltage output by the signal adjustment circuit module enters the AD module; the AD module adjusts the signal adjustment circuit module. The output DC voltage is converted into collected data, and the collected data is sent to the DMD control board through the LVDS bus; at the same time, the DMD control board sends the DA control data to control the DA module to convert the negative high voltage control digital signal input through the LVDS bus into a negative high voltage control voltage The signal is sent to the negative high voltage module, and the -200~-500V negative high voltage generated by the negative high voltage module is supplied to the PMT of the spectrometer dispersion detection system through the PMT power supply interface.

The signal adjustment circuit module includes a gain control interface, a front-end floating pin amplifier circuit, a common amplifier circuit, a background button interface, a subtractor circuit, a phase-sensitive interface, an integral discharge interface and a charge storage circuit; the gain signal input by the gain control interface The front-end floating pin amplifier circuit converts the weak current signal into a weak voltage signal; the background deduction signal input from the background deduction interface starts to act to control the subtractor circuit to offset the background voltage; the weak voltage signal deducted from the background signal is sent to the ordinary The amplifying circuit is amplified and input to the phase-sensitive interface; the phase-sensitive signal is input from the phase-sensitive interface, and the voltage signal of the control sine waveform is converted into a square wave; the integral discharge signal is input to the charge storage circuit from the integral discharge interface, and the charge storage circuit integrates the discharge signal. Under control, the square wave is converted into DC voltage and output to AD module.

The non-dispersive acquisition control board and the reference channel control board have the same structure as the dispersion acquisition control board; the non-dispersive acquisition control board receives the weak current signal of the non-dispersive detection system PMT of the spectrometer through the PMT signal acquisition interface, and outputs the spectrometer through the PMT power supply interface. -200～-500V negative high voltage required by the PMT of the non-dispersive detection system; the reference channel control board receives the weak current signal of the PMT of the spectrometer light source spectral line correction system through the PMT signal acquisition interface, and outputs the spectrometer light source spectral line through the PMT power supply interface Negative high voltage of -200~-500V required to correct the PMT of the system.

The currents of the two HCL lamps are the HCL lamp current of Channel A and the HCL lamp current of Channel B; the main current and auxiliary current of the HCL lamp of Channel A are obtained by the following methods:

1. The STM32 processing module calculates the hexadecimal signal m _Am required by the main current of the A-channel HCL lamp and the hexadecimal signal m _Aa required by the auxiliary current of the A-channel HCL lamp according to formulas (1) and (2): Then m _Am and m _Aa are converted into corresponding binary signals m _BIN1 and m _BIN2 and output to the DA module;

Among them, I _Ar ——A channel lamp current ratio setting value in hexadecimal form;

I _As ——the total current setting value of channel A lamp in hexadecimal form;

R'——the resistance value of the sampling resistor of the two-way HCL drive circuit module in hexadecimal form;

V'——the reference voltage of the DA module in hexadecimal form;

n ₁ ′——The amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module is in hexadecimal form;

n ₂ ′——the amplification factor of the second-stage amplifier circuit of the two-way HCL drive circuit module in hexadecimal form;

2. In the DA module, m _BIN1 and m _BIN2 are respectively converted into the HCL lamp main driving voltage V _1A of channel A and the auxiliary driving voltage V _1B of HCL lamp of channel A by formulas (3) and (4):

Where V is the reference voltage of the DA module;

3. The main driving voltage V _1A of the HCL lamp in channel A and the auxiliary driving voltage V _1B of the HCL lamp in channel A enter the HCL driving voltage module of channel A, and after passing through the first-stage amplifier circuit, the second-stage amplifier circuit and the sampling resistor, generate A channel HCL lamp main actual current I' _Am and auxiliary actual current I'_Aa;

n ₁ ′——the amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module;

n ₂ ′——the magnification of the secondary amplifier circuit of the two-way HCL drive circuit module;

The process of generating the main and auxiliary actual current I' _Bm and the auxiliary actual current I' _Ba of the B-channel HCL is the same as that of the A-channel.

The lighting timing interface in the two-way HCL drive circuit module, the gain control interface, the background button interface, the phase-sensitive interface and the integral discharge interface in the dispersion acquisition board are all active low-level interfaces; for two-way HCL lamps, use Lighting at the same time, the lighting sequence adopts square wave, the lighting time is T ₁ , and the lighting time is T ₇ ; the lighting sequence and the timing of each interface of the signal adjustment circuit module are as follows:

When the two-way HCL lamps are turned off, the gain control interface and the phase-sensitive interface are disconnected, the background button is closed, and the subtractor circuit accumulates the background voltage collected under the light-off state, and the time is T ₈ ; At the moment of lighting, the background deduction interface is disconnected. After the background voltage stabilization time T2 has passed, the gain control interface and the phase sensitive interface are closed, and the subtractor circuit begins to offset the background voltage. _The duration of the background voltage offset is _T5 , and the background deduction is completed once. The closing time of the gain control interface and the phase-sensitive interface is T ₆ ; then the gain control interface and the phase-sensitive interface are disconnected and start to enter the next background deduction period; wherein, T ₆ =T ₅ -T ₂ ;

During the closing time _T6 of the gain control interface, the front-end floating pin amplifier circuit amplifies the weak voltage, the gain control interface is disconnected when the background button is closed, and the disconnection time is _T9 , _T9 = _{T8 +} T2 ;

During the closing time _T6 of the phase-sensitive interface, the phase-sensitive interface converts the sine wave voltage signal with the background deducted and amplified into a square wave; at the same time, the charge storage circuit starts to integrate and store the square wave; when the background deduction interface is closed, the phase The sensitive interface is disconnected, and the charge storage circuit stops integrating and storing the square wave at the same time; the disconnection time of the phase-sensitive interface is T ₉ ;

When the background button is closed, the gain control interface and the phase-sensitive interface are disconnected, the integral discharge interface is closed and begins to discharge, and the DC voltage is output to the AD module. The discharge time is T ₄ ; after the discharge time T ₄ , the integral discharge interface is disconnected. ON to complete a discharge cycle.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention adopts the hard connection mode of the motherboard socket to reduce the external leads, enhance the integration and improve the stability. Based on the powerful functions of the dedicated DMD control board, it can directly control the motherboard through the LVDS bus, IO port and CAN bus, select and control the light source equipment, and realize the high-speed acquisition of dispersion, non-dispersion and reference channel signals. .

(2) Different from the multi-channel non-dispersive AFS lighting method in turn according to a specific time sequence, the present invention can realize simultaneous lighting based on DMD dispersion technology, so as to improve the rapidity of detection work time, and improve multi-channel graded detection to simultaneous detection , which can avoid the influence of different light intensities of atomic fluorescence at different times, reduce the influence of noise, improve the stability, and save the target element solution at the same time, and the target element solution can be collected together for detection.

(3) This kind of atomic fluorescence spectrometer retains the original non-dispersive system while newly developing the dispersive detection system, and also adds the reference channel system. The present invention can realize the simultaneous measurement and control of three systems. function to overcome spectral interference, while the reference channel system corrects the spectral lines of the light source to reduce other unwanted effects.

(4) The acquisition sensitivity and data stability of photoelectric signals are improved and improved. A shielding box is added to the acquisition part of the circuit board, and the signal acquisition input terminal adopts a floating pin method to reduce the noise impact of the fast high-voltage signal on the acquisition device; at the same time, based on the phase-sensitive, gain and integral discharge control signals, a buckle background The control signal can effectively reduce the background, improve the signal strength, and greatly improve the signal-to-noise ratio.

Description of drawings:

FIG. 1 is a structural block diagram of the present invention.

FIG. 2 is a block diagram of the structure of the signal adjustment circuit.

FIG. 3 is a three-dimensional structural diagram of the present invention.

Figure 4 is the flow chart of the lighting function of the lamp board

FIG. 5 is a timing diagram of a gain signal, an integral discharge signal, a phase sensitive signal, a timing sequence of a background deduction signal, and a lighting timing sequence.

FIG. 6 is a partial enlarged view of FIG. 5 .

In the picture: 1, 24V power supply interface; 2, 24V to ±12V power conversion module; 3, 24V to 5V power conversion module; 4, motherboard; 5, socket; 6, STM32 debugging interface; 7, B channel HCL power supply Interface; 8. Channel A HCL power supply interface; 9. The shielding box of the dispersion acquisition control board; 10. The PMT signal acquisition interface of the dispersion acquisition board; 11. The shielding box of the non-dispersive acquisition control board; 12. The PMT of the non-dispersive acquisition board Signal acquisition interface; 13. The shielding box of the reference channel control board; 14. The PMT signal acquisition interface of the reference channel board; 15. The PMT power supply interface of the reference channel board; 16. The PMT power supply interface of the non-dispersive acquisition board; 17 , PMT power supply interface of dispersion acquisition board; 18, LVDS bus; 19, LVDS bus; 20, LVDS bus; 21, light board; 22, IO interface; 23, HCL power supply high voltage module; 24, dual street lamp identification interface; 25, CAN bus; 26, IO interface; 27, IO interface.

Detailed ways:

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

1. Functional structure of the present invention

As shown in Figures 1 and 3, the measurement and control system of the DMD-based dispersive atomic fluorescence spectrometer of the present invention is mainly composed of a mother board 4, a lamp board 21, a dispersion acquisition control board, a non-dispersive acquisition control board and a reference channel control board. It consists of 5 PCB boards.

The dedicated software of the PC (host computer) controls the DMD control board through the network port. The control core of the DMD control board is FPGA, which controls the measurement and control system through LVDS bus, IO line and CAN bus 25, so that each module of the measurement and control system works in coordination.

As shown in Figures 1 and 3, the motherboard 4 is hard-connected to the lamp board 21 through the socket 5 for power supply and data transmission; Connect to supply power and transmit data. In order to prevent the outside world from causing noise interference to the weak current signal to be detected, the dispersion acquisition control board, non-dispersive acquisition control board and reference channel control board are respectively wrapped by all-iron (or copper) shielding boxes 9, 11 and 13, except for the Outside the hard-connected sockets on motherboard 4, the external interfaces are only PMT power supply ports 15, 16, 17 and PMT signal acquisition ports 10, 12, and 14; PMT signal acquisition ports 10, 12, and 14 all use BNC plugs.

1. Motherboard 4

As shown in Figures 1 and 3, 24V power supply interface 1 is fixed on motherboard 4, 24V to ±12V power conversion module 2, 24V to 5V power conversion module 3, DMD signal de-jitter module, IO interfaces 22, 26, 27, LVDS bus 18, 19, 20, dual street lamp identification interface 24 and CAN bus 25. The 24V DC voltage of the external power supply supplies power to the entire measurement and control system through the 24V power supply interface 1; the 24V DC voltage is converted into ±12V and 5V DC voltage by the 24V to ±12V power conversion module 2 and 24V to 5V power conversion module 3, respectively, and is provided to the light board 21. Dispersion acquisition control board, non-dispersive acquisition control board and reference channel control board; Motherboard 4 communicates with DMD control board through three LVDS buses 18, 19, 20 to achieve fast transmission of part of data (including DA chip selection, DA Timing, DA control data (digital signal), AD chip selection, AD timing, AD control data (analog signal), and acquisition data transformed by the signal adjustment circuit); because the LVDS bus is a high-speed differential signal interface, it is necessary to generate/de-differentiate The module performs signal conversion, and then leads to the lamp board 21, the dispersion acquisition control board, the non-dispersive acquisition control board and the reference channel control board; The gain signal, integral discharge signal, phase sensitive signal, deduction background signal, AD busy signal, AD start signal and lighting sequence of the lamp board 21 required by the reference channel control board; the motherboard 4 communicates with the DMD control board through the CAN bus 25 Communication, transmits the lighting signal, lamp identification signal and reply signal required by the light board 21; the DMD signal debounce module is a reserved module, and receives the DMD synchronization signal input by the DMD control board without debounce through the IO interfaces 27 and 26 respectively. And the DMD synchronizing signal which is debounced is output; the motherboard 4 transmits the output lamp identification signal of the DMD control board through the lamp identification interface 24 .

2. Light board

On the light board 21 are fixed an HCL power supply high voltage module 23 , a two-way HCL drive circuit module, an STM32 processing module, a DA module, an HCL lamp identification module, and a channel A HCL power supply interface 8 and a channel B HCL power supply interface 7 .

The control program in the STM32 processing module is programmed through the STM32 debugging interface 6.

The light board 21 works normally under the support of the motherboard 4 . The binary double-lane lamp model data is transmitted to the HCL lamp identification module through the double-lane lamp identification interface 24. The HCL lamp identification module organizes the double-lane lamp model data into two channels of 4-bit binary digital signals representing the lamp model. Input to the STM32 processing module; STM32 The processing module converts the binary digital signal operation into a hexadecimal reply signal, and sends it to the DMD control board through the CAN bus 25. The DMD control board returns its reply signal to the host computer through the network port; the host computer compares the predefined 12 The HCL code value translates the reply signal into the corresponding dual-channel HCL lamp model; the STM32 processing module receives the two-channel HCL lamp current (including the two-channel main current and the two-channel auxiliary current, which need to be set) transmitted by the DMD control board through the CAN bus 25. That is, the lighting signal in Figure 1), through the calculation to generate two 8-bit digital signals driven by HCL, enter the DA module, and the DA module converts it to generate two HCL driving voltages to the two HCL driving circuit modules to generate the expected HCL lamp At the same time, the lighting sequence output by the DMD control board is sent to the two-way HCL drive circuit module through the IO interface 22 to provide a square wave with a certain duty ratio (such as 1:30) for the two-way HCL lamps to achieve pulse lighting; finally, The 24V DC voltage is input to the HCL power supply high-voltage module 23 to generate 300V voltage and divided into two channels. At the same time, the two-way HCL driver circuit module combines the HCL lamp current with the 300V voltage and passes the A channel HCL power supply interface 8 and B channel HCL power supply interface 7 Externally supply power to two HCL lamps.

3. Control panel

The dispersion acquisition control board works for the spectrometer dispersion detection system, the non-dispersive acquisition control board works for the spectrometer non-dispersive detection system, and the reference channel control board works for the spectrometer light source spectral line correction system. The circuit structure of the three control boards is the same, the difference is that the dispersion acquisition control board receives the weak current signal of the PMT of the spectrometer dispersion detection system, and outputs the negative high voltage of -200~-500V required by the PMT of the spectrometer dispersion detection system, with different interfaces. Adopt LVDS bus 20, PMT signal acquisition interface 10 and PMT power supply interface 17; the non-dispersive acquisition control board receives the weak current signal of the PMT of the non-dispersive detection system of the spectrometer, and outputs -200～-500V required by the PMT of the non-dispersive detection system of the spectrometer Negative high voltage, different interfaces adopt LVDS bus 19, PMT signal acquisition interface 12 and PMT power supply interface 16; the reference channel control board receives the weak current signal of the PMT of the spectrometer light source spectral line correction system, and outputs the PMT of the spectrometer light source spectral line correction system The required -200--500V negative high voltage, the different interfaces use the LVDS bus 18, the PMT signal acquisition interface 14 and the PMT power supply interface 15. Now take the dispersion acquisition control board as an example: the dispersion acquisition control board includes a signal adjustment circuit module, an AD module, a negative high voltage module, and a DA module; the DMD control board sends out the integral discharge signal, the background signal, the gain signal and the phase sensitive signal to the Signal adjustment circuit module; the signal acquisition interface 10 collects the weak current signal of the PMT of the spectrometer dispersion detection system and sends it to the signal adjustment circuit module, and then the weak current signal is converted into a weak voltage signal in the front-end floating pin amplifier circuit, and then the gain signal is Under the action of deducting background signal and phase-sensitive signal, it is amplified by gain, deducting background signal, converted into square wave, and finally DC voltage is obtained under the action of integral discharge signal. The DC voltage output by the signal adjustment circuit module enters the AD module.

The DMD control board sends AD control data to control the AD module to convert the DC voltage output by the signal adjustment circuit module into collected data. The collected data is sent to the DMD control board through the LVDS bus 20, and the DMD control board returns the collected data to the host through the network port. The host computer performs data processing to generate the corresponding atomic fluorescence spectrum; at the same time, the DMD control board sends the DA control data to control the DA module to convert the negative high voltage control digital signal input through the LVDS bus 20 into a negative high voltage control voltage signal ( 0-5v analog voltage signal) to the negative high voltage module, the -200～-500V negative high voltage voltage generated by the negative high voltage module is sent to the PMT power supply interface 17 of the dispersion acquisition board to supply power to the PMT of the spectrometer dispersion detection system.

As shown in Figure 2, the signal adjustment circuit module includes a gain control interface, a front-end floating pin amplifier circuit, an ordinary amplifier circuit, a background button interface, a subtractor circuit, a phase-sensitive interface, an integral discharge interface and a charge storage circuit; The function of the gain signal input by the interface, the front-end floating pin amplifier circuit converts the weak current signal into a weak voltage signal; then the background deduction signal input from the deduction background interface begins to act to control the subtractor circuit to offset the background voltage; then the deduction out The weak voltage signal of the background signal is sent to the ordinary amplifier circuit to be amplified by 5000 times and then input to the phase-sensitive interface; then the phase-sensitive signal is input by the phase-sensitive interface, and the phase-sensitive signal controls the voltage signal of the sine wave to be converted into a square wave, and finally the integrated discharge signal is composed of The integral discharge interface is input to the charge storage circuit, and the charge storage circuit converts the square wave into a DC voltage under the control of the integral discharge signal and outputs it to the AD module.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. The scope of the present invention All changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced within the present invention as defined by the appended claims, rather than the foregoing description. Any reference signs in the claims should not be construed as limiting the related claims, without departing from the spirit and scope of the technical solutions of the present invention, and should be included in the scope of the claims of the present invention.

As shown in Figure 4, the STM32 receives the lighting signal through the CAN bus 25, including I _Ar , I _As , I _Br and I _Bs ;

Specifically:

Channel A lamp current ratio setting value is I _Ar (main current/total current, hexadecimal, unit: 100%)

The total current setting value of channel A lamp is I _As (main current + auxiliary current, hexadecimal, unit: mA)

Channel B lamp current ratio setting value is I _Br (main current/total current, hexadecimal, unit: 100%)

The total current setting value of channel B lamp is I _Bs (main current + auxiliary current, hexadecimal, unit: mA)

Take the lighting of lane A as an example:

The main current and auxiliary current of channel A HCL lamp are obtained by the following methods:

1. The STM32 processing module calculates the hexadecimal signal m _Am required by the main current of the A-channel HCL lamp and the hexadecimal signal m _Aa required by the auxiliary current of the A-channel HCL lamp according to formulas (1) and (2): Then m _Am and m _Aa are converted into corresponding binary signals m _BIN1 and m _BIN2 , namely the 8-bit digital signals driven by the HCL lamp of channel A, and output to the DA module;

Among them, I _Ar ——A channel lamp current ratio setting value in hexadecimal form;

I _As ——the total current setting value of channel A lamp in hexadecimal form;

R'——the resistance value of the sampling resistor of the two-way HCL drive circuit module in hexadecimal form;

V'——the reference voltage of the DA module in hexadecimal form;

n ₁ ′——The amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module is in hexadecimal form;

n ₂ ′——the amplification factor of the second-stage amplifier circuit of the two-way HCL drive circuit module in hexadecimal form;

2. In the DA module, m _BIN1 and m _BIN2 are respectively converted into the HCL lamp main driving voltage V _1A of channel A and the auxiliary driving voltage V _1B of HCL lamp of channel A by formulas (3) and (4):

Where V is the reference voltage of the DA module;

3. The main driving voltage V _1A of the HCL lamp in channel A and the auxiliary driving voltage V _1B of the HCL lamp in channel A enter the HCL driving voltage module of channel A, and after passing through the first-stage amplifier circuit, the second-stage amplifier circuit and the sampling resistor, generate A channel HCL lamp main actual current I' _Am and auxiliary actual current I'_Aa;

n ₁ ′——the amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module;

n ₂ ′——The amplification factor of the second-stage amplifier circuit of the two-way HCL drive circuit module.

Similarly, the process of generating the HCL main and auxiliary actual current I' _Bm and the auxiliary actual current I' _Ba of channel B is the same as that of channel A.

As shown in Figure 5 and Figure 6, T ₁ , the lighting time of two HCL lamps; T ₂ , the stabilization time of the background current to cancel; T ₃ , the delay time of the DMD inversion processing; T ₄ , the discharge time; T ₅ , the time to cancel the background current ; T ₆ , gain time (phase-sensitive time); T ₇ , two-way HCL light-off time; T ₈ , background deduction time; T ₉ , gain control interface disconnection time (phase-sensitive interface off time); T ₁₀ , integral Disconnection time of the discharge interface.

The lighting timing interface in the two-way HCL drive circuit module, the gain control interface in the dispersion acquisition board, the background button interface, the phase-sensitive interface and the integral discharge interface are all active low-level interfaces, that is, the interface when the low level is 0 Closed, the interface is disconnected when the high level is 1. Therefore, the corresponding action is performed when the digital signal is 0 in the timing sequence.

For two-way HCL lamps: use simultaneous lighting, and the lighting sequence adopts a square wave of _1:30 , lights up at T1, and turns off at T7, and the relationship between the two is _{T7 = 30T1} ;

For the background deduction signal: when the two HCL lights are turned off, the gain control interface and the phase sensitive interface are disconnected, the deduction background interface is closed, the subtractor circuit and the ordinary amplifier circuit form a closed loop, and the subtractor circuit begins to accumulate in the light-off state. The collected current (that is, the background current) has a time of T ₈ ; at the moment when the two-way HCL lamps are lit, the atomic fluorescence signal begins to be input to the signal adjustment circuit module, and the background button is disconnected, and the background current is stabilized after a short period of offsetting. After time _T2 , the gain control interface and the phase sensitive interface are closed, and the subtractor circuit begins to cancel the background current of the atomic fluorescence signal (that is, the background current is deducted), and the duration of canceling the background current is T5 _; The signal of the PMT will have a lag, so the time delay T3 to offset the background current is to close the background deduction interface again to complete a deduction _of the background, and at the same time, the gain control interface and the phase sensitive interface are disconnected to form a closed loop again and begin to enter the next deduction background cycle; Wherein, the existence relationship is T ₅ =T ₁ +T ₃ , T ₈ =T ₇ -T ₃ =10T ₁ -T ₃ ;

For the gain signal: after the background current stabilization time T ₂ is cancelled, the gain control interface is closed, and the weak voltage output by the amplifier circuit of the front-end floating pin is controlled to be amplified, and the gain time is T ₆ , T ₆ =T ₅ -T ₂ =T ₁ +T ₃ -T ₂ ; the gain control interface is disconnected while closing the background interface, and the disconnection time is T ₉ , T ₉ =T ₈ +T ₂ =10T ₁ -T ₃ +T ₂ ;

For the phase-sensitive signal: after canceling the background current stabilization time T2, the phase _- sensitive interface is closed, and the sine waveform voltage signal after the background is deducted and amplified by 5000 times is converted into a square wave, and the charge storage circuit starts to integrate and store the square wave. The phase-sensitive time is T ₆ , T ₆ =T ₅ -T ₂ =T ₁ +T ₃ -T ₂ ; when the background interface is closed, the phase-sensitive interface is disconnected, and the charge storage circuit stops integrating and storing the square wave. The opening time is T ₉ , T ₉ =T ₈ +T ₂ =10T ₁ -T ₃ +T ₂ ;

For the integral discharge signal: when the background button is closed, the gain control interface and the phase sensitive interface are disconnected, the integral discharge interface is closed to start discharging, and the DC voltage is output to the AD module. _The discharge time is T4 _; after the discharge time T4 , the integral discharge interface is disconnected, and a discharge cycle is completed.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole, The technical solutions in each embodiment can also be appropriately combined to form other modes that can be understood by those skilled in the art.

Claims (7)

1. a kind of measurement and control system based on the dispersion type atomic fluorescence spectrometer of DMD, it is characterized in that comprising mother board (4), lamp board (21), dispersion acquisition control board, non-dispersion acquisition control board and reference channel control board altogether 5 A PCB board; the light board (21), the chromatic dispersion acquisition control board, the non-dispersive acquisition control board and the reference channel control board are hard-connected to the motherboard (4) through the socket, and the chromatic dispersion acquisition control board, the non-dispersive acquisition control board and the parameter The channel control boards are respectively wrapped by shielding boxes; the external interfaces on each shielding box include a PMT power supply interface and a PMT signal acquisition interface; the dispersion acquisition control board, the non-dispersive acquisition control board and the reference channel control board are The structure is the same; the dispersion acquisition control board collects the weak current signal of the PMT of the spectrometer dispersion detection system through the PMT signal acquisition interface, and supplies -200~-500V negative high voltage voltage to the PMT of the spectrometer dispersion detection system through the PMT power supply interface; The PMT signal acquisition interface receives the weak current signal of the PMT of the non-dispersive detection system of the spectrometer, and supplies -200~-500V negative high voltage voltage to the PMT of the non-dispersive detection system of the spectrometer through the PMT power supply interface; the reference channel control board receives the spectrometer through the PMT signal acquisition interface The weak current signal of the PMT of the light source spectral line correction system supplies -200~-500V negative high voltage to the PMT of the spectrometer light source spectral line correction system through the PMT power supply interface; the motherboard (4) passes the LVDS bus, IO interface and CAN bus (25) Communicate with the DMD control board; the HCL power supply high-voltage module (23), the two-way HCL drive circuit module, the STM32 processing module, the DA module, the HCL lamp identification module and the A channel HCL power supply are fixed on the lamp board (21). The interface (8) and the B-channel HCL power supply interface (7); the lamp sockets of the two-way HCL output the binary dual-channel lamp model data and are transmitted to the HCL lamp identification module through the dual-channel lamp identification interface (24). The lamp model data is organized into two binary digital signals representing the lamp model and input to the STM32 processing module; the STM32 processing module converts the binary digital signal operation into a hexadecimal reply signal, and sends it to the DMD control board through the CAN bus (25); The STM32 processing module receives the two-way HCL lamp currents that need to be set transmitted by the DMD control board through the CAN bus (25), and generates two-way HCL-driven digital signals through calculation to enter the DA module, and the DA module converts them to generate two-way HCL driving voltages To the two-way HCL drive circuit module, the expected HCL lamp current is generated; the lighting sequence output by the DMD control board is sent to the two-way HCL drive circuit module through the IO interface; 24V DC voltage is input to the HCL power supply high-voltage module (23) to generate 300V voltage and Divided into two channels, at the same time, the two-way HCL drive circuit module combines the HCL lamp current and 300V voltage and connects to the two-way HCL lamp through the A-channel HCL power supply interface (8) and the B-channel HCL power supply interface (7). Power on. 2 . The measurement and control system of a DMD-based dispersive atomic fluorescence spectrometer according to claim 1 , wherein the PMT signal acquisition interface adopts a BNC plug. 3 . 3. the measurement and control system of the dispersive atomic fluorescence spectrometer based on DMD according to claim 1, is characterized in that on the described motherboard (4), fixed 24V power supply interface (1), 24V turns ±12V power conversion module (2) ), 24V to 5V power conversion module (3), IO interface, LVDS bus, dual light identification interface (24), CAN bus (25); the external power supply 24V DC voltage supplies power to the entire measurement and control system through the 24V power supply interface (1) ; The 24V DC voltage is converted into ±12V and 5V DC voltage by the 24V to ±12V power conversion module (2) and the 24V to 5V power conversion module (3), respectively, and is supplied to the lamp board (21), the dispersion acquisition control board, and the non-dispersive acquisition. Control board and reference channel control board. 4. the measurement and control system of the dispersion type atomic fluorescence spectrometer based on DMD according to claim 1, is characterized in that described dispersion acquisition control board comprises signal adjustment circuit module, AD module, negative high voltage module, DA module; DMD control board sends out The integral discharge signal, the background signal, the gain signal and the phase sensitive signal are transmitted to the signal adjustment circuit module through the IO interface; the weak current signal of the spectrometer dispersion detection system PMT collected through the PMT signal acquisition interface is sent to the signal adjustment circuit module, and the weak current The signal is first converted into a weak voltage signal in the front-end floating pin amplifier circuit. Under the action of the gain signal, the background signal, and the phase-sensitive signal, it is amplified by the gain, the background signal is deducted, and converted into a square wave. Finally, under the action of the integral discharge signal The DC voltage is obtained; the DC voltage output by the signal adjustment circuit module enters the AD module; the AD module converts the DC voltage output by the signal adjustment circuit module into collected data, and the collected data is sent to the DMD control board through the LVDS bus; at the same time, the DMD control board Send the DA control data to control the DA module to convert the negative high voltage control digital signal input through the LVDS bus into a negative high voltage control voltage signal to the negative high voltage module. Check the PMT of the system. 5. the measurement and control system of the dispersive atomic fluorescence spectrometer based on DMD according to claim 4, is characterized in that described signal adjustment circuit module comprises gain control interface, front-end dangling pin amplifier circuit, common amplifier circuit, buckle background interface, Subtractor circuit, phase-sensitive interface, integral discharge interface and charge storage circuit; under the action of the gain signal input from the gain control interface, the front-end floating pin amplifier circuit converts the weak current signal into a weak voltage signal; The signal starts to act to control the subtractor circuit to cancel the background voltage; the voltage signal deducted from the background signal is sent to the ordinary amplifier circuit for amplification and then input to the phase-sensitive interface; the phase-sensitive signal is input from the phase-sensitive interface to control the conversion of the weak voltage signal of the sine waveform It is a square wave; the integral discharge signal is input to the charge storage circuit through the integral discharge interface, and the charge storage circuit converts the square wave into a DC voltage and outputs it to the AD module under the control of the integral discharge signal. 6. the measurement and control system of the dispersive atomic fluorescence spectrometer based on DMD according to claim 1, is characterized in that two-way HCL lamp current is respectively A road HCL lamp current and B road HCL lamp current; A road HCL lamp main current and The auxiliary current is obtained by the following methods: 1. The STM32 processing module calculates the hexadecimal signal m _Am required by the main current of the A-channel HCL lamp and the hexadecimal signal m _Aa required by the auxiliary current of the A-channel HCL lamp according to formulas (1) and (2): Then m _Am and m _Aa are converted into corresponding binary signals m _BIN1 and m _BIN2 and output to the DA module;

Among them, I _Ar ——A channel lamp current ratio setting value in hexadecimal form; I _As ——the total current setting value of channel A lamp in hexadecimal form; R'——the resistance value of the sampling resistor of the two-way HCL drive circuit module in hexadecimal form; V'——the reference voltage of the DA module in hexadecimal form; n ₁ ′——The amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module is in hexadecimal form; n ₂ ′——the amplification factor of the second-stage amplifier circuit of the two-way HCL drive circuit module in hexadecimal form; 2. In the DA module, m _BIN1 and m _BIN2 are respectively converted into the HCL lamp main driving voltage V _1A of channel A and the auxiliary driving voltage V _1B of HCL lamp of channel A by formulas (3) and (4):

Where V is the reference voltage of the DA module; 3. The main driving voltage V _1A of the HCL lamp in channel A and the auxiliary driving voltage V _1B of the HCL lamp in channel A enter the HCL driving voltage module of channel A, and after passing through the first-stage amplifier circuit, the second-stage amplifier circuit and the sampling resistor, generate A channel HCL lamp main actual current I' _Am and auxiliary actual current I'_Aa;

n ₁ ′——the amplification factor of the first-level amplifier circuit of the two-way HCL drive circuit module; n ₂ ′——the magnification of the secondary amplifier circuit of the two-way HCL drive circuit module; The process of generating the main and auxiliary actual current I' _Bm and the auxiliary actual current I' _Ba of the B-channel HCL is the same as that of the A-channel. 7. the measurement and control system of the dispersive atomic fluorescence spectrometer based on DMD according to claim 5, is characterized in that the lighting sequence interface in the two-way HCL drive circuit module, the gain control interface in the dispersion acquisition board, the buckle background interface, the phase The interfaces used by the sensitive interface and the integral discharge interface are all active low; for the two-way HCL lamps, simultaneous lighting is adopted, and the lighting sequence is square wave, the lighting time is T ₁ , and the lighting time is T ₇ ; The timing of each interface of the signal adjustment circuit module is as follows: When the two-way HCL lamps are turned off, the gain control interface and the phase-sensitive interface are disconnected, the background button is closed, and the subtractor circuit accumulates the background voltage collected under the light-off state, and the time is T ₈ ; At the moment of lighting, the background deduction interface is disconnected. After the background voltage stabilization time T2 has passed, the gain control interface and the phase sensitive interface are closed, and the subtractor circuit begins to offset the background voltage. _The duration of the background voltage offset is _T5 , and the background deduction is completed once. The closing time of the gain control interface and the phase-sensitive interface is T ₆ ; then the gain control interface and the phase-sensitive interface are disconnected and start to enter the next background deduction period; wherein, T ₆ =T ₅ -T ₂ ; During the closing time _T6 of the gain control interface, the front-end floating pin amplifier circuit amplifies the weak voltage, the gain control interface is disconnected when the background button is closed, and the disconnection time is _T9 , _T9 = _{T8 +} T2 ; During the closing time _T6 of the phase-sensitive interface, the phase-sensitive interface converts the sine wave voltage signal with the background deducted and amplified into a square wave; at the same time, the charge storage circuit starts to integrate and store the square wave; when the background deduction interface is closed, the phase The sensitive interface is disconnected, and the charge storage circuit stops integrating and storing the square wave at the same time; the disconnection time of the phase-sensitive interface is T ₉ ; When the background button is closed, the gain control interface and the phase-sensitive interface are disconnected, the integral discharge interface is closed and begins to discharge, and the DC voltage is output to the AD module. The discharge time is T ₄ ; after the discharge time T ₄ , the integral discharge interface is disconnected. ON to complete a discharge cycle.

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