A multi-channel gas sensor test system

Abstract

The present invention provides a multi-channel gas sensor test system, including a test circuit, the test circuit including a plurality of sub-test circuits, each sub-test circuit corresponding to a gas sensor; one end of an adjustable power supply is connected to a main control unit, and the other end is connected to a first end of a follower filter module; the first end of the follower filter module is connected to a gas sensor connector, and the second end is connected to an IO data interface of an ADC module, and the gas sensor connector is connected to the gas sensor; one end of a power consumption resistor is connected to the follower filter module, and the other end is grounded; one end of a matching resistor is connected to an analog switch, and the other end is grounded; the IO data interface of the ADC module is connected to the analog switch. By corresponding one sub-test circuit to each gas sensor, independent control of each sensor can be completed while implementing multi-channel testing.

Description

Technical Field

[0001] The invention relates to the technical field of gas sensor gas-sensitive characteristic testing, in particular to a multi-channel gas sensor testing system. Background Art

[0002] At present, there are two testing methods for studying the gas-sensitive characteristics of semiconductor gas sensors: static and dynamic gas distribution. The sensor is installed in a test chamber, and a certain gas of known concentration and volume is injected into the test chamber. By collecting the sensor's response signal, the gas-sensitive response characteristics of the sensor to the gas can be obtained. In order to improve the test efficiency, the existing gas-sensitive characteristic test equipment has a multi-channel test function.

[0003] Since different gas-sensitive materials may have different polarization voltages, and different polarization voltages may correspond to different sensitivities, different measurement voltages can change the sensitivity of the gas sensor. At present, the multi-channel test equipment on the market has an overall adjustment mode for the heating voltage of multiple sensors in the equipment. For multi-channel test equipment, the heating voltage, measurement voltage, matching resistance and other parameters of each channel cannot be adjusted independently, so it is only suitable for batch testing, not suitable for testing different types of gas sensors at the same time, and cannot be personalized. In addition, during the research and development process of gas sensors, it is necessary to test the gas-sensitive characteristics of gas sensors at different heating temperatures, measurement voltages and matching resistances to optimize the working temperature, measurement voltage and matching resistance to obtain the best gas-sensitive characteristics of the material. Traditional gas-sensitive test equipment uses multiple manual adjustments when setting the heating voltage, measurement voltage and matching resistance of the test gas sensor. The test data needs to be manually processed and classified. It takes a lot of time to complete a set of optimal working curves, and the data processing is cumbersome.

[0004] In addition to the above problems, the current gas sensor testing equipment also has the following problems:

[0005] 1. Traditional gas-sensitive test equipment uses static gas distribution during the test of gas sensors. In order to speed up the diffusion of the injected gas and reduce the gas mixing time, an electric fan that accelerates the diffusion is installed in the test chamber. However, the gas mixing time is still greater than the response time of the fast-response gas sensor, so the response time of the gas sensor cannot be accurately measured, and the recovery time of the gas sensor cannot be accurately tested.

[0006] 2. Traditional gas-sensitive testing equipment uses static gas distribution during the test of gas sensors. There is a certain error in the accuracy of the gas distribution. At the same time, the test gas adsorbed in the test chamber will also bring a certain gas distribution error, affecting the test accuracy of the gas sensor.

[0007] 3. When the male and female interfaces of the traditional test device and the circuit adapter board device are connected, at least one of the devices needs to be moved, so the positions of the two cannot be relatively fixed, and the integration of the test system is low;

[0008] 4. When testing gas sensors, traditional gas-sensitive testing equipment uses a single gas distribution method, mostly static gas distribution tests. The test gas after the test may be toxic and harmful, posing a certain hazard to the testers in the laboratory. However, the test equipment cannot centrally process the waste gas after the test. Summary of the invention

[0009] The technical problem to be solved by the present invention is how to independently adjust the parameters of each channel in a multi-channel gas sensor testing system.

[0010] The present invention solves the above technical problems through the following technical means:

[0011] A multi-channel gas sensor test system, comprising a test circuit and a plurality of gas sensors corresponding to the test circuit, wherein the test circuit comprises a plurality of sub-test circuits, each of which corresponds to a gas sensor; the sub-test circuit comprises a gas sensor connector, an adjustable power supply, a follower filter module, an analog switch, a power consumption resistor, a matching resistor network, an ADC module, and a main control unit;

[0012] One end of the adjustable power supply is connected to the main control unit, and the other end is connected to the first end of the follower filter module; the ADC module includes an IO data interface and an IO communication interface, the first end of the follower filter module is connected to the gas sensor connector, and the second end is connected to the IO data interface of the ADC module, and the gas sensor connector is connected to the gas sensor; one end of the power consumption resistor is connected to the first end of the follower filter module, and the other end is grounded; one end of the matching resistor is connected to the analog switch, and the other end is grounded; the IO data interface of the ADC module is connected to the analog switch, and the IO communication interface of the ADC module is connected to the main control unit.

[0013] Preferably, the matching resistors are multiple connected in parallel to form a matching resistor network; one end of the matching resistor network is grounded, and the other end is connected to the analog switch.

[0014] Preferably, there are two adjustable power supplies and four follower filter modules, and the ADC module includes four IO data interfaces and one IO communication interface; one end of the adjustable power supply 1a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 1b, one end of the adjustable power supply 2a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 2b; the ADC module includes four IO data interfaces and one IO communication interface, the first end of the follower filter module 1b is connected to the gas sensor connector, the second end of the follower filter module 1b is connected to the first IO data interface C1 of the ADC module, the first end of the follower filter module 2b is connected to the gas sensor connector, and the second end of the follower filter module 2b is connected to the A The second IO data interface C2 of the DC module is connected, the first end of the follower filter module 3b is connected to the gas sensor connector, the second end of the follower filter module 3b is connected to the fourth IO data interface C4 of the ADC module, the first end of the follower filter module 4b is connected to the gas sensor connector, and the second end of the follower filter module 4b is connected to the third IO data interface C3 of the ADC module; the gas sensor connector is connected to the gas sensor; one end of the power consumption resistor is connected to the first end of the follower filter module 4b, and the other end is grounded; one end of the matching resistor network is connected to the analog switch, and the other end is grounded; the fourth IO data interface C4 of the ADC module is connected to the analog switch, and the IO communication interface of the ADC module is connected to the main control unit.

[0015] Preferably, the multi-channel gas sensor testing system further comprises an Internet access module or a wireless communication module, and the main control unit is communicatively connected to the Internet access module or the wireless communication module.

[0016] Preferably, the multi-channel gas sensor testing system also includes a box, a gas distribution system, a collection unit, and a transmission module; the box includes a gas distribution chamber and at least one circuit chamber; the gas distribution system is located in the gas distribution chamber; the collection unit includes a test device and a collection board; the test device is fixed on the wall of the box; the collection board and the transmission module are located in the circuit chamber; the test device is connected to the gas path of the gas distribution system and is communicatively connected to the collection board, and the collection board is communicatively connected to the transmission module.

[0017] Preferably, the test device includes a test chamber, and the gas sensor is located in the test chamber; an air inlet and an air outlet are provided on opposite sides of the test chamber, and the test chamber is connected to the gas distribution system through the air inlet and the air outlet; a first diverter plate is fixed between the air inlet and the gas sensor; the direction of the air flow entering from the air inlet is perpendicular to the surface of the first diverter plate; and a plurality of first diverter holes are dispersedly provided on the first diverter plate.

[0018] Preferably, a second diverter plate is fixed between the first diverter plate and the gas sensor, and the second diverter plate is parallel to the first diverter plate; a plurality of second diverter holes are distributedly opened on the second diverter plate; and the first diverter holes and the second diverter holes are staggered.

[0019] Preferably, a third diverter plate is fixed between the gas sensor and the gas outlet; the third diverter plate is parallel to the first diverter plate; a plurality of third diverter holes are dispersedly opened on the third diverter plate; the flow areas on the first diverter plate and the second diverter plate are both smaller than the flow area on the third diverter plate.

[0020] Preferably, the testing device includes a test cavity body and a carrying plate; the middle portion of the test cavity body is concave to form the test cavity; the front side of the carrying plate covers the test cavity body so that the test cavity forms a sealed space; a plurality of sensor interfaces are provided on the carrying plate for electrically connecting the gas sensor; the sensor measuring points on the back side of the carrying plate are exposed.

[0021] Preferably, the acquisition unit also includes a circuit adapter board device, which is fixed on the wall of the box; the circuit adapter board device includes a circuit adapter board, a lower protective cover, and a driving mechanism; the lower protective cover has a cavity for accommodating the circuit adapter board; in the cavity, the circuit adapter board and the lower protective cover are slidably fixed; the carrier plate horizontally leads out the external interface toward one side of the circuit adapter board, and the circuit adapter board horizontally leads out the circuit adapter board slot toward one side of the carrier plate; the driving mechanism drives the circuit adapter board to move away from or close to the carrier plate to achieve on-off coordination between the circuit adapter board slot and the external interface.

[0022] Preferably, a slide groove is provided at the bottom of the circuit adapter board, and a slide rail cooperating with the slide groove is provided on the upper surface of the lower protective cover; the circuit adapter board is slidably fixed on the lower protective cover through the cooperation of the slide groove and the slide rail.

[0023] Preferably, it also includes an upper protective cover; the lower protective cover and the upper protective cover are both roughly U-shaped structures; the upper protective cover is buckled on the lower protective cover, and a cavity for accommodating the circuit adapter board is formed between the two; a hole is opened in the upper cover plate of the box body, and the lower protective cover is embedded in the hole, and the two top ends of the upper protective cover and the lower protective cover have flanges to form an installation skirt, and the upper protective cover, the lower protective cover, and the board surface are fixed into a whole through the installation skirt.

[0024] Preferably, the driving mechanism includes a long hole at the U-shaped bottom of the upper protective cover and a handle installed on the top of the circuit adapter board; the long axis direction of the long hole is consistent with the sliding direction of the circuit adapter board; and the handle extends out of the long hole.

[0025] Preferably, the gas distribution system includes a gas diaphragm pump, a first three-way valve, a two-way valve and a second three-way valve, an air inlet interface, an air outlet interface, an injection port, and a discharge interface; according to the gas flow direction, the air inlet interface, the first three-way valve, the gas diaphragm pump, the test chamber, the second three-way valve, and the air outlet interface are connected in sequence through pipelines; the inlet of the gas distribution chamber is connected to the injection port through a pipeline, the injection port is connected to the second three-way valve, and the outlet of the gas distribution chamber leads to two pipelines, one of which is connected to the discharge interface through the two-way valve, and the other is connected to the first three-way valve.

[0026] The advantages of the present invention are:

[0027] 1. The present invention achieves the individual adjustment of the heating voltage, measuring voltage and matching resistance of an independent channel by corresponding one sub-test circuit to each gas sensor, and can test the sensitivity of gas sensors with different heating voltages in the same space-time environment, and measure the optimal working voltage of the sensor at one time; in addition, for the same gas-sensitive material, different measuring voltages can improve the sensitivity of the gas sensor;

[0028] By individually controlling the parameters of each gas sensor, dynamic scanning of the heating voltage, measuring voltage and matching resistance of the gas sensor in each test channel is achieved. The resistance RS-heating voltage VH, sensor resistance RS-measuring resistance VC and sensor resistance RS-matching resistance RL of multiple similar gas sensors can be collected synchronously to form a curve and database without multiple manual adjustments.

[0029] 2. The present invention divides the voltage by designing power consumption resistors and matching resistor networks, and adjusts the heating voltage and measuring voltage of the sensor through two adjustable power supplies to meet the test requirements. Each gas sensor can be adjusted individually, and the test is flexible and adaptable.

[0030] 3. The test system provided by the present invention divides the cavity into multiple independent chambers to avoid mutual influence between the components and improve the test accuracy. In addition, the test device and the circuit adapter board are fixed on the wall of the box, and the operating components are outside the box, which is convenient for operation;

[0031] 4. Furthermore, the first diverter plate is used to disperse and mix the gas before it contacts the gas sensor and quickly fill the cavity, pushing out the original gas in all directions, completely replacing the gas without residue, and improving the test accuracy from multiple aspects such as shortening the mixing time and quickly replacing the gas; the second diverter plate is used, and the diverter holes of the first diverter plate are arranged in a staggered manner, so that the gas can be further dispersed and mixed, so that the gas can completely fill the cavity and push out the original gas horizontally, ensuring the test accuracy; the third diverter plate is used, and the design method of the flow area is larger than that of the first diverter plate and the second diverter plate is adopted to ensure that the gas does not flow back after being pushed out, thereby improving the replacement rate;

[0032] 5. Furthermore, the sensor measuring points on the back of the carrier plate are exposed, which is convenient for real-time manual use of power meters, voltmeters and other tools to directly measure various parameters of the gas sensor, which is convenient for operation and verification;

[0033] 6. Furthermore, the circuit adapter board adopts sliding advance and retreat to realize the connection and disconnection of the external interface between the test device, which is convenient to operate and the interface connection is accurate, laying the foundation for the integration of the system;

[0034] 7. The test device and the circuit adapter board are relatively fixed, and the design of horizontal external interface and slot is adopted. The circuit adapter board is slid by the driving mechanism to complete the connection and disconnection of the interface, so as to achieve the relative fixation of the position of the test device and the circuit adapter board, realize the assembly of the system, and facilitate movement and storage. In particular, the circuit adapter board adopts sliding advance and retreat to achieve the connection and disconnection of the external interface between the test device, which is convenient to operate and the interface connection is accurate;

[0035] 8. The circuit adapter board is fixed by the upper and lower protective covers, which is convenient for disassembly and assembly. The drive mechanism is set up through this simple structure, which is ingeniously designed.

[0036] 9. The gas distribution system comprehensively considers synthetic gas distribution, gas bag gas distribution, gas distribution chamber injection, etc., and adopts the coordinated operation of multiple three-way valves, two-way valves, pipelines, gas distribution chambers, and test chambers. The gas distribution chamber is used as a part of the gas distribution pipeline. Except for injection-type gas distribution, there is no need to disassemble the gas distribution chamber; barrier-free switching between multiple gas distribution forms is achieved, which greatly reduces the test preparation work.

[0037] The test system provided by the present invention is based on the design of the driving mechanism of the circuit adapter board device, the comprehensive consideration of the gas distribution pipeline, and the independent control of the multi-channel gas sensor. It realizes the integrated design of the test system through multi-faceted collaborative operation, which can not only provide test accuracy, but also make the test system compact, reduce the assembly work before testing, and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the test system in an embodiment of the present invention;

[0039] Figure 2 Schematic diagram of the internal cavity distribution structure of the test system in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the explosion structure of the gas sensor testing device in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the test chamber body in an embodiment of the present invention;

[0042] Figure 5It is a schematic diagram of the overall structure of the circuit adapter board device in the test system of an embodiment of the present invention;

[0043] Figure 6 It is a schematic diagram of the assembly structure of the circuit adapter board and the lower protective cover in the circuit adapter board device in the test system according to an embodiment of the present invention;

[0044] Figure 7 A schematic diagram of the connection structure of the gas distribution system in the test system according to an embodiment of the present invention;

[0045] Figure 8 A schematic diagram of the gas circuit structure of the high-pressure synthetic gas distribution mode in the test system according to an embodiment of the present invention;

[0046] Fig. 9 Schematic diagram of the gas circuit structure for collecting the gas distribution mode of the air bag in the test system according to the embodiment of the present invention;

[0047] Fig.10 A schematic diagram of the gas circuit structure of the gas distribution mode of the gas distribution chamber in the test system according to an embodiment of the present invention;

[0048] Fig.11 A circuit schematic diagram of a test system according to an embodiment of the present invention;

[0049] Fig.12 The following is a flowchart of the operation of the test system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] This embodiment provides a multi-channel gas sensor testing system. Figure 1 , 2 As shown, it includes a box 1, a gas distribution system 2, a collection unit 3, a power supply unit 4, a main control unit, an Ethernet input and output unit 6, a host computer (not shown) and a human-machine interface (not shown). The power supply unit 4 supplies power to other components.

[0052] The box body 1 provided in this embodiment is a cubic structure as a whole. The inner cavity of the box body 1 is divided into an air path chamber 11, a first circuit chamber 12, and a second circuit chamber 13 by a partition. In order to reduce thermal interference and electromagnetic interference, the air path chamber 11 is located above the first circuit chamber 12 and the second circuit chamber 13, and is separated by a plate with good thermal insulation performance. The first circuit chamber 12 and the second circuit chamber 13 are arranged side by side horizontally and are separated by a plate with good electromagnetic shielding performance. In addition, cooling fans (not shown in the figure) are installed on the side walls of the air path chamber 11, the first circuit chamber 12, and the second circuit chamber 13, and the heat dissipation of each chamber meets the system operation requirements.

[0053] In this embodiment, the power supply unit 4, the main control unit, and the Ethernet input and output unit 6 are arranged in the second circuit chamber 13. The pipeline of the gas distribution system 2 is arranged in the gas distribution chamber 11, and the collection unit 3 includes a test device 31, a circuit adapter board device 32 and a collection board 33, wherein the test device 31 and the circuit adapter board device 32 are fixed on the upper cover plate 14 of the box body 1, and the collection board 33 is fixed in the first gas circuit chamber 11. The test device 31 is connected to the circuit adapter board device 32 for communication, and the circuit adapter board device is connected to the collection board 33 for communication.

[0054] In this embodiment, Figure 3 , Figure 4 As shown, the testing device 31 includes a testing chamber body 311 , a testing chamber air inlet interface 312 , a testing chamber air outlet interface 313 , a carrying plate 314 and a sealing pressing plate 315 .

[0055] The middle part of the test cavity body 311 is concave to form a test cavity 3111, and the gas sensor is located in the test cavity 3111. An air inlet and an air outlet (not shown) are provided on the test cavity 3111, and the air inlet and the air outlet are respectively connected to the test cavity air inlet interface 312 and the test cavity air outlet interface 313. In order to avoid turbulence when the gas flows in the cavity and affect the test accuracy, the four corners of the test cavity 3111 are arc-shaped, and the whole is in the shape of an oblong hole. A first diverter plate is arranged between the air inlet of the test cavity 3111 and the gas sensor, and the air flow direction is perpendicular to the surface of the first diverter plate. A plurality of first diverter holes are distributed on the first diverter plate. After the gas enters from the air inlet, due to the limited flow area of ​​the air inlet and the fast air flow speed, it basically takes the form of a gas beam after entering the test cavity 3111. When the gas beam encounters the first diverter plate, it is blocked and dispersed, and continues to move forward from each first diverter hole to achieve the purpose of dispersing the airflow, filling the entire cavity, and making the airflow fully contact with the gas sensor. The effect is better when it is applied to mixed gases. Specifically: after multiple gases enter the test cavity 3111, they are diverted by the first diverter plate and mixed before contacting the gas sensor, so as to achieve the purpose of improving the test accuracy. In addition, the dispersed gas fills the test cavity 3111, which can fully push out the original gas in the test cavity 3111 to achieve rapid replacement.

[0056] In order to further disperse and mix the gas, the present embodiment further provides a second diverter plate 3112 between the first diverter plate and the gas sensor, and the second diverter holes are dispersedly opened on the second diverter plate 3112. In order to fully mix and replace the gas, the present embodiment staggers the first diverter holes and the second diverter holes to achieve secondary obstructed diversion and mixing of the airflow.

[0057] In order to prevent gas backflow or residual incomplete discharge, the third diverter plate 3113 is further provided between the gas sensor and the gas outlet in this embodiment, and a plurality of third diverter holes are also dispersedly provided on the third diverter plate 3113. In order to allow the gas to pass quickly, the flow area on the third diverter plate 3113 is set to be larger than the flow area of ​​the first diverter plate and the second diverter plate in this embodiment. The diverter holes on the first diverter plate 3114, the second diverter plate 3112 and the third diverter plate 3113 can be evenly distributed or irregularly arranged, preferably evenly distributed.

[0058] The first diverter plate 3114, the second diverter plate 3112 and the third diverter plate 3113 are all installed through the grooves on the side wall of the test chamber 3111, and are all perpendicular to the bottom wall of the test chamber 3111. When the second diverter plate 3112 is fixed at the end of the arc at the air inlet of the test chamber 3111, the first diverter plate 3114 is located between the second diverter plate 3112 and the air inlet, and the third diverter plate 3113 is fixed at the end of the arc at the air outlet of the test chamber 3111, the diverter and mixing effect is optimal.

[0059] A temperature and humidity sensor and a pressure sensor (not shown) may be disposed in the test cavity 3111 to detect the humidity, temperature control and gas pressure in the test cavity.

[0060] The carrier plate 314 is a PCB board, on which a plurality of sensor interfaces (not shown) are arranged. When in use, the gas sensor (not shown) is installed at the sensor interface, and the carrier plate 314 covers the opening of the test cavity 3111, so that the gas sensor is located between the second diverter plate 3112 and the third diverter plate 3113. And the external interface 3141 of the carrier plate 314 is arranged outside the test cavity body 311. A first sealing gasket 316 is usually arranged between the carrier plate 314 and the test cavity body 311 for sealing and protection. The first sealing gasket 316 is provided with a first opening 3161 corresponding to the opening of the test cavity 3111.

[0061] The sealing plate 315 covers the back of the carrier plate 314 and is sealed and connected to the test chamber body 311 by screws. In order to ensure the sealing effect, a second sealing pad 317 is usually set between the sealing plate 315 and the carrier plate 314. The first sealing pad 316 and the second sealing pad 317 are both silicone pads. The third opening 3151 and the second opening 3171 can be opened in the sealing plate 315 and the second sealing pad 317 in sequence to expose the sensor measurement point on the back of the carrier plate 314, so as to facilitate the use of tools such as power meters and voltmeters to directly measure various parameters of the gas sensor.

[0062] When switching gases, gas B enters the test cavity 3111 from the test cavity air inlet interface 312, and is diverted twice by the first diverter plate 3114 and the second diverter plate 3112, so that gas B diffuses to the entire cross section of the test cavity 3111. In addition, the flow rate of gas B is very fast, so the gas A previously left in the test cavity 3111 can be quickly discharged. It can be seen that the above structure enables the gas switching to be completed quickly when switching gases. The simulation shows that the switching time is less than 1s, and the response time and recovery time of the gas sensor can be accurately tested.

[0063] In addition, if gas B is a mixed gas, when gas B enters the test chamber 3111 from the air inlet interface 312, the mixed gas B is initially mixed between the air inlet and the first diverter plate 3114, and then pushed forward through the through hole on the first diverter plate 3114, and then secondary mixed in the space formed between the first diverter plate 3114 and the second diverter plate 3112, and then pushed forward, and contacted and tested with the gas sensor in the space formed by the second diverter plate 3112 and the third diverter plate 3113. Then it flows to the air outlet through the air holes on the third diverter plate 3113. The above process uses a double-layer pre-mixing chamber for the test chamber 3111 to ensure that the mixed gas is evenly mixed during the test, and the third diverter plate 3113 can prevent gas backflow, thereby improving the test accuracy.

[0064] In this embodiment, a hole is opened in the upper cover plate 14 of the box body 1, the test cavity 3111 is adapted to and embedded in the hole, and the skirt formed around the test cavity body 311 is fixed to the upper cover plate 14 of the box body 1 by screws, so that the entire test device 31 is fixed on the upper cover plate 14 of the box body 1.

[0065] like Figure 5 , Figure 6 As shown, the circuit adapter board device 32 includes a circuit adapter board slot 321 , a circuit adapter board 322 , a fixing plate 323 , a slide rail 324 , a lower protective cover 325 , a moving handle 326 and an upper protective cover 327 .

[0066] The lower protective cover 325 is generally in a U-shaped structure, and the two top edges are turned to form a mounting skirt. Similarly, a hole is opened in the upper cover plate 14 of the box body 1, and the lower protective cover 325 is covered under the hole. The mounting skirt is fixed to the upper cover plate 14 of the box body 1 by screws, so that the lower protective cover 325 and the box body 1 form a whole. The bottom of the lower protective cover 325 is provided with a wiring hole 3251 for the power line and the data line.

[0067] The upper protective cover 327 is generally in an inverted U-shaped structure, and both ends also have mounting skirts, and are fixed to the upper cover plate 14 as a whole by screws. The upper protective cover 327 is buckled on the lower protective cover 325, and a cavity for accommodating the circuit adapter board 322 is formed between the two. The circuit adapter board 322 is fixed on the fixed plate 323, and the fixed plate 323 is slidably fixed with the lower protective cover 325 through the slide rail 324. In this embodiment, the fixed plate 323 is a cubic structure, and the circuit adapter board 322 is a circuit board, which is fixed on the side of the fixed plate 323 facing the carrier plate 314.

[0068] The carrier board 314 leads to the external interface 3141 horizontally on one side of the circuit adapter board, and the circuit adapter board 322 leads to the circuit adapter board slot 321 horizontally on one side of the carrier board, forming a plug-in structure with the external interface 3141 of the carrier board. The plug-in and pull-out mechanism of the circuit adapter board slot 321 and the external interface 3141 of the carrier board is:

[0069] A long hole is provided at the U-shaped bottom of the upper protective cover 327, and the long axis direction of the long hole is consistent with the sliding direction of the circuit adapter board. A handle 326 is installed on the top of the fixed plate 323, and the handle 326 extends out of the long hole. By pushing the handle 326, the circuit adapter board can be moved, thereby realizing the plugging and unplugging action of the circuit adapter board slot 321 and the external interface 3141 of the carrier board. After the test is completed, push the handle 326 in the opposite direction to separate the circuit adapter board slot 321 from the external interface 3141 of the carrier board 314. A structure such as a lead screw can also be used to drive the circuit adapter board 322 to move forward or backward, so that the circuit adapter board 322 and the external interface 3141 of the carrier board 314 are electrically connected and signal connected. The movable handle 326 can also be made into an electric handle, which does not require manual push.

[0070] The structure of the gas distribution system 2 is as follows Figure 7As shown, it includes a gas flow meter 23, a gas diaphragm pump, a first three-way valve 21, a two-way valve 26 and a second three-way valve 22, an air inlet interface 24, an air outlet interface 25, an injection port 27, and a discharge interface 28. According to the gas flow direction, the air inlet interface 24, the first three-way valve 21, the gas diaphragm pump, the gas flow meter 23, the test chamber, the second three-way valve 22, and the air outlet interface 25 are connected in sequence through pipelines. The inlet of the gas distribution chamber is connected to the injection port 27 through a pipeline, and the injection port 27 is connected to the second three-way valve 22. The outlet of the gas distribution chamber leads to two pipelines, one of which is connected to the discharge interface 28 through the two-way valve 26, and the other is connected to the first three-way valve 21. Combined with Figure 1 , Figure 2 , wherein the gas diaphragm pump, the gas distribution chamber and the gas pipeline are all arranged in the gas circuit chamber 11, and the valve switches of the first three-way valve 21, the two-way valve 26 and the second three-way valve 22, the air inlet interface 24, the air outlet interface 25, the injection port 27 and the discharge interface 28 are all fixed on the upper surface of the upper cover plate 14 through the upper cover plate 14 of the box body 1 for easy operation. The gas flow meter 23 is fixed on the outer wall of the side plate of the box body 1 for easy observation. For easy identification, the connection relationship of the various components of the gas distribution system 2 can be depicted on the upper cover plate 14.

[0071] In this embodiment, the gas distribution system 2 has three working modes: high-pressure synthesis gas distribution mode, gas collection bag distribution mode and gas distribution chamber injection mode.

[0072] High pressure synthesis gas distribution mode Figure 8 As shown, each high-pressure synthesis gas bag is connected to the air inlet interface 24 through the flow controller MFC. The high-pressure synthesis gas enters the air inlet interface 24 according to a certain ratio through the flow controller MFC, and the first three-way valve 21 switches the gas circuit to the gas diaphragm pump. The gas passes through the gas diaphragm pump and the gas flow meter 23 and enters the test chamber. After the test is completed, the gas is switched to the gas outlet interface 25 through the second three-way valve 22 and emptied to the safe gas treatment point for centralized waste gas treatment.

[0073] The air bag distribution mode is as follows: Fig. 9 As shown, the gas to be measured is collected in a collection air bag, which has two inlet and outlet interfaces, which are respectively connected to the air inlet interface 24 and the air outlet interface 25 on the gas distribution system 2. The first three-way valve 21 is adjusted to the air inlet interface 24 to communicate with the gas diaphragm pump, and the second three-way valve 22 is adjusted to the air outlet interface 25 to communicate with the outlet of the test chamber. Start the gas diaphragm pump to allow the gas to be measured in the collection air bag to circulate in the pipeline and the test chamber. This realizes gas recycling and reduces pollution.

[0074] The injection mode of the gas distribution chamber is as follows Fig.10As shown, the first three-way valve 21 connects the gas diaphragm pump and the gas distribution chamber, the second three-way valve 22 connects the test chamber outlet and the injection port 27, the two-way valve 26 is closed, and then the gas diaphragm pump is started to allow the gas to be tested in the gas distribution chamber to circulate in the pipeline. Through the injection port 27, a micro-syringe is used to inject the gas or liquid to be tested to adjust the concentration and type of the gas to be tested in the circulation system. After the test is completed, the two-way valve 26 can be opened, and the gas in the system can be purged and cleaned through the exhaust interface 28. This gas distribution mode has the lowest cost. Figure 8 , Fig. 9 , Fig.10 The bold lines represent the gas paths in the three modes.

[0075] This embodiment provides a test circuit for a multi-channel gas sensor test system. The test circuit includes multiple sub-test circuits, each of which corresponds to a gas sensor. Fig.11 As shown, the operation block diagram is as follows Fig.12 As shown, taking 10 channels as an example, 10 sensor interfaces are installed on the carrier board 314, and 10 gas sensors can be detected simultaneously. Correspondingly, 10 gas sensor connectors are installed on the circuit adapter board 322, and each gas sensor connector is connected to a collection board 33.

[0076] like Fig.11 As shown in the schematic diagram of the sub-test system circuit, the acquisition board 33 includes a gas sensor connector, an adjustable power supply 1a, an adjustable power supply 2a, a follower filter module 1b, a follower filter module 2b, a follower filter module 3b, a follower filter module 4b, an analog switch, a power consumption resistor 10, a matching resistor network 20, an ADC module, a main control unit and a network port module. The control module can also communicate with the PC via wireless transmission.

[0077] One end of the adjustable power supply 1a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 1b. One end of the adjustable power supply 2a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 2b. The ADC module includes four IO data interfaces and one IO communication interface. The IO data interface is specifically an analog signal interface. The first end of the follower filter module 1b is connected to the gas sensor connector, and the second end of the follower filter module 1b is connected to the first IO data interface C1 interface of the ADC module. The first end of the follower filter module 2b is connected to the gas sensor connector, and the second end of the follower filter module 2b is connected to the second IO data interface C2 interface of the ADC module. The first end of the follower filter module 3b is connected to the gas sensor connector, and the second end of the follower filter module 3b is connected to the fourth IO data interface C4 interface of the ADC module. The first end of the follower filter module 4b is connected to the gas sensor connector, and the second end of the follower filter module 4b is connected to the third IO data interface C3 interface of the ADC module. The gas sensor connector is connected to the gas sensor. One end of the power consumption resistor 10 is connected to the first end of the follower filter module 4b, and the other end is grounded. One end of the matching resistor network 20 is connected to the analog switch, and the other end is grounded; the fourth IO data interface C4 of the ADC module is connected to the analog switch, and the IO communication interface of the ADC module is connected to the main control unit. The main control unit is connected to the network port module for communication.

[0078] The working principle is as follows: after receiving the command from the network port module, the main control unit adjusts the heating voltage VH, the measuring voltage VC, and the matching resistor RL of the gas sensor. The heating voltage VH and the measuring voltage VC are adjusted by the main control unit to control the adjustable power supply 1a and the adjustable power supply 2a. After the heating voltage VH and the measuring voltage VC are adjusted, the matching voltage VL and the power voltage VP will change. By detecting the changes in the matching voltage VL and the power voltage VP, the resistance value of the gas sensor is changed, and the relevant parameters of the detected gas sensor are obtained according to the resistance value changes. The matching resistor network 20 is adjusted by the main control unit to control the switching of the analog switch.

[0079] The gas sensor is divided by the matching resistor network 20 (100R-100M) and then filtered by the following filter module 3b before entering the ADC module.

[0080] In this embodiment, the ADC module is an ADC converter with multiple input channels, and the ADC converter performs data communication with the main control unit via an SPI interface.

[0081] This embodiment uses 10 gas sensors for detection. After the main control unit collects the data of the gas sensors 1-10, it packages the data and sends it to the network port module.

[0082] The main control unit is a single-chip microcomputer MCU, and the communication method with the network port module is UART communication.

[0083] like Fig.12 The operation process of the test system shown in the figure is that the main control unit (MCU) is electrically connected to the sensor power supply (adjustable power supply); the sensor power supply unit is electrically connected to the sensor, the sensor is electrically connected to the acquisition unit (ADC module), the acquisition unit is electrically connected to the main control unit, and the main control unit is communicated with the host computer PC through the Ethernet input and output unit.

[0084] The host PC sets the relevant commands for sensor testing, such as the heating voltage VH, measuring voltage VC, matching resistor RL, and power consumption resistor of each channel (gas sensor), and then clicks the "Configure Command Send" button. The PC will transmit the set command to the network port module of the corresponding acquisition board through the Ethernet input and output unit, and the network port module will transmit the command to the single-chip microcomputer MCU. After receiving the command, the single-chip microcomputer MCU will control the adjustable power supply and ADC module to achieve the independent adjustment of the heating voltage, measuring voltage and matching resistor of the independent channel; after the control is completed, the ADC module will continuously convert the analog electrical signal of the sensor into a digital signal and transmit it to the single-chip microcomputer MCU, and the single-chip microcomputer MCU will transmit the digital signal to the PC through the network port module and the Ethernet input and output unit for processing. By controlling each parameter of each gas sensor separately, the dynamic scanning of the heating voltage, measuring voltage and matching resistor of each test channel gas sensor is realized, and the 10 gas sensor resistors RS-heating voltage VH, sensor resistors RS-measuring resistors VC and sensor resistors RS-matching resistors RL can be collected synchronously to form curves and databases.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-channel gas sensor testing system, characterized in that: The invention comprises a test circuit and a plurality of gas sensors corresponding to the test circuit, wherein the test circuit comprises a plurality of sub-test circuits, each of which corresponds to a gas sensor; the sub-test circuit comprises a gas sensor connector, an adjustable power supply, a follower filter module, an analog switch, a power consumption resistor, a matching resistor network, an ADC module, and a main control unit; One end of the adjustable power supply is connected to the main control unit, and the other end is connected to the first end of the follower filter module; the ADC module includes an IO data interface and an IO communication interface, the first end of the follower filter module is connected to the gas sensor connector, and the second end is connected to the IO data interface of the ADC module, and the gas sensor connector is connected to the gas sensor; one end of the power consumption resistor is connected to the first end of the follower filter module, and the other end is grounded; one end of the matching resistor is connected to the analog switch, and the other end is grounded; the IO data interface of the ADC module is connected to the analog switch, and the IO communication interface of the ADC module is connected to the main control unit; It also includes a box, a gas distribution system, a collection unit, and a transmission module; the box includes a gas distribution chamber and at least one circuit chamber; the gas distribution system is located in the gas distribution chamber; the collection unit includes a test device and a collection board; the test device is fixed to the box wall; the collection board and the transmission module are located in the circuit chamber; the test device is connected to the gas path of the gas distribution system and is in communication connection with the collection board, and the collection board is in communication connection with the transmission module; The test device comprises a test chamber, in which the gas sensor is located; an air inlet and an air outlet are provided on opposite sides of the test chamber, and the test chamber is connected to the gas distribution system through the air inlet and the air outlet; a first diverter plate is fixed between the air inlet and the gas sensor; the direction of the air flow entering from the air inlet is perpendicular to the surface of the first diverter plate; a plurality of first diverter holes are distributed on the first diverter plate; The matching resistors are connected in parallel to form a matching resistor network; one end of the matching resistor network is grounded, and the other end is connected to the analog switch; A second flow diverter plate is also fixed between the first flow diverter plate and the gas sensor, and the second flow diverter plate is parallel to the first flow diverter plate; a plurality of second flow diverter holes are distributed on the second flow diverter plate; the first flow diverter holes and the second flow diverter holes are staggered; A third diverter plate is also fixed between the gas sensor and the gas outlet; the third diverter plate is parallel to the first diverter plate; a plurality of third diverter holes are dispersedly opened on the third diverter plate; the flow areas on the first diverter plate and the second diverter plate are both smaller than the flow area on the third diverter plate; The test device comprises a test cavity body and a carrying plate; the middle part of the test cavity body is concave to form the test cavity; the front side of the carrying plate covers the test cavity body, so that the test cavity forms a sealed space; a plurality of sensor interfaces are arranged on the carrying plate, which are used to electrically connect the gas sensor; the sensor measuring points on the back side of the carrying plate are exposed; The acquisition unit also includes a circuit adapter board device, which is fixed on the wall of the box; the circuit adapter board device includes a circuit adapter board, a lower protective cover, and a driving mechanism; the lower protective cover has a cavity for accommodating the circuit adapter board; in the cavity, the circuit adapter board and the lower protective cover are slidably fixed; the carrier plate horizontally leads out the external interface toward one side of the circuit adapter board, and the circuit adapter board horizontally leads out the circuit adapter board slot toward one side of the carrier plate; the driving mechanism drives the circuit adapter board to move away from or close to the carrier plate to achieve on-off coordination between the circuit adapter board slot and the external interface.

2. A multi-channel gas sensor testing system according to claim 1, characterized in that: There are two adjustable power supplies and four follower filter modules. The ADC module includes four IO data interfaces and one IO communication interface. One end of the adjustable power supply 1a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 1b. One end of the adjustable power supply 2a is connected to the main control unit, and the other end is connected to the first end of the follower filter module 2b. The ADC module includes four IO data interfaces and one IO communication interface. The first end of the follower filter module 1b is connected to the gas sensor connector, and the second end of the follower filter module 1b is connected to the first IO data interface C1 interface of the ADC module. The first end of the follower filter module 2b is connected to the gas sensor connector, and the second end of the follower filter module 2b is connected to the ADC The module's second IO data interface C2 interface is connected, the first end of the follower filter module 3b is connected to the gas sensor connector, the second end of the follower filter module 3b is connected to the fourth IO data interface C4 interface of the ADC module, the first end of the follower filter module 4b is connected to the gas sensor connector, and the second end of the follower filter module 4b is connected to the third IO data interface C3 interface of the ADC module; the gas sensor connector is connected to the gas sensor; one end of the power consumption resistor is connected to the first end of the follower filter module 4b, and the other end is grounded; one end of the matching resistor network is connected to the analog switch, and the other end is grounded; the fourth IO data interface C4 of the ADC module is connected to the analog switch, and the IO communication interface of the ADC module is connected to the main control unit.

3. A multi-channel gas sensor testing system according to claim 1 or 2, characterized in that: The gas distribution system includes a gas diaphragm pump, a first three-way valve, a two-way valve and a second three-way valve, an air inlet interface, an air outlet interface, an injection port, and a discharge interface; according to the gas flow direction, the air inlet interface, the first three-way valve, the gas diaphragm pump, the test chamber, the second three-way valve, and the air outlet interface are connected in sequence through pipelines; the inlet of the gas distribution chamber is connected to the injection port through a pipeline, the injection port is connected to the second three-way valve, and the outlet of the gas distribution chamber leads to two pipelines, one of which is connected to the discharge interface through the two-way valve, and the other is connected to the first three-way valve.

Images