CN220490731U - Propellant gas concentration monitoring sensor - Google Patents

Propellant gas concentration monitoring sensor Download PDF

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Publication number
CN220490731U
CN220490731U CN202420025260.3U CN202420025260U CN220490731U CN 220490731 U CN220490731 U CN 220490731U CN 202420025260 U CN202420025260 U CN 202420025260U CN 220490731 U CN220490731 U CN 220490731U
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pin
chip
sensor
operational amplifier
gas concentration
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佘姗姗
孙翔
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Nanjing Yixintong Control Equipment Technology Co ltd
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Nanjing Yixintong Control Equipment Technology Co ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

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Abstract

The utility model discloses a propellant gas concentration monitoring sensor which comprises a main shell, a gas concentration detection unit, a signal processing unit, a fixed bracket, a rotary connecting piece, an upper cover, a front end sealing cover and an electric connector, wherein the main shell is provided with a plurality of sensors; one side of the fixed bracket is fixed with the upper cover through the rotary connecting piece, the other side of the fixed bracket is connected with one side of the main shell, and the other side of the main shell is fixed with the front end sealing cover; the electric connector, the signal processing unit and the gas concentration detection unit are sequentially connected, the electric connector is arranged in the hollow cavity of the rotary connecting piece, and an output interface of the electric connector is led out from the upper cover and is used for outputting a detection result of the propellant gas concentration monitoring sensor; the input end of the electric connector is connected with the signal processing unit, a gas concentration detection unit and a signal processing unit which are connected are fixedly arranged in a hollow cavity of the main shell, and a gas concentration signal detected by the gas concentration detection unit is processed by the signal processing unit and then is output through the electric connector.

Description

Propellant gas concentration monitoring sensor
Technical Field
The utility model relates to the technical field of sensors, in particular to a propellant gas concentration monitoring sensor.
Background
Gas sensors are needed to identify, detect, measure and confirm the presence of gases in an industrial environment. Depending on the volume and concentration of the gas in the region, the gas sensor will generate a corresponding potential difference, which will change the resistance value of the material inside the sensor. And then generates an electrical signal according to the change of the resistance value, and finally the electrical signal is measured as an output voltage. The gas concentration sensor is a gas sensor for detecting the concentration of a gas in different scenes.
In the prior art, a gas concentration sensor is installed and used on a vehicle, most of the gas concentration sensor is used for monitoring the concentration of oxygen or other toxic gases, the modularized design of the gas concentration sensor is less, and when the vehicle runs at a high speed, the interface of the gas concentration sensor vibrates, so that the accurate monitoring of the gas concentration is not facilitated.
Disclosure of Invention
The technical purpose is that: aiming at the defects in the prior art, the utility model discloses a propellant gas concentration monitoring sensor which is of a modularized design integrated with a sensor structure, has a small structural design and is convenient to use on a vehicle; the mechanical interface is easy to disassemble and assemble, can be installed on a vehicle running dynamically, and can keep long-term reliable running under the condition of unstable machinery.
The technical scheme is as follows: in order to achieve the technical purpose, the utility model adopts the following technical scheme.
A propellant gas concentration monitoring sensor comprising: the device comprises a main shell, a gas concentration detection unit, a signal processing unit, a fixed bracket, a rotary connecting piece, an upper cover, a front end sealing cover and an electric connector; one side of the fixed support is fixed with the upper cover through the rotary connecting piece, the other side of the fixed support is connected with one side of the main shell, and the other side of the main shell is fixed with the front end sealing cover;
the electric connector, the signal processing unit and the gas concentration detection unit are sequentially connected, the electric connector is arranged in the hollow cavity of the rotary connecting piece, and an output interface of the electric connector is led out from the upper cover and is used for outputting the detection result of the propellant gas concentration monitoring sensor; the input end of the electric connector is connected with the signal processing unit, a gas concentration detection unit and a signal processing unit which are connected are fixedly arranged in a hollow cavity of the main shell, the gas concentration detection unit is an electrochemical intelligent sensor, and a gas concentration signal detected by the gas concentration detection unit is processed by the signal processing unit and then is output through the electric connector; the gas concentration detection unit is close to the front end sealing cover and is used for detecting gas concentration information when the front end sealing cover is opened for use.
Preferably, the signal processing unit comprises a sensor board and a data processing board which are connected, wherein an analog-to-digital conversion circuit, a sensor signal output circuit and a power supply circuit are arranged on the sensor board; the data processing board is provided with an electrochemical sensor, a potentiostat circuit, a level holding circuit and a current-to-voltage circuit; the power supply circuit is used for supplying power to the potentiostat circuit, the level holding circuit, the current-to-voltage circuit and the analog-to-digital conversion circuit; the electrochemical sensor is connected with the potentiostat circuit, the level holding circuit and the current-to-voltage circuit, the analog-to-digital conversion circuit and the sensor signal output circuit are sequentially connected.
Preferably, the pin 1 of the electrochemical intelligent sensor is a CE pin, which is used as a counter electrode of the electrochemical intelligent sensor, the pin 2 is a WE1 pin, which is used as a working electrode of the electrochemical intelligent sensor, and the pin 3 is a RE pin, which is used as a reference electrode of the electrochemical intelligent sensor.
Preferably, the constant potential rectifier circuit and the current-to-voltage circuit share an operational amplifier chip U1; the operational amplifier chip U1 includes two parts: U1-A in the potentiostat circuit and U1-B in the current-to-voltage circuit;
in the potentiostat circuit, a pin 2 of an operational amplifier chip U1 is connected with a RE pin of an electrochemical intelligent sensor through a resistor R3 and a resistor R2, a pin 3 of the operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R10, and a pin 2 of the operational amplifier chip U1 is connected with a pin 3 of the operational amplifier chip U1 through a capacitor C2; the pin 1 of the operational amplifier chip U1 is connected with the CE pin of the electrochemical intelligent sensor through a resistor R1, and the pin 1 of the operational amplifier chip U1 is connected with the pin 2 of the operational amplifier chip U1 through a capacitor C1 and a resistor R3;
in the current-to-voltage circuit, a pin 5 of an operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R9, a pin 6 of the operational amplifier chip U1 is connected with a WE1 pin of an electrochemical intelligent sensor through the resistor R5, the pin 5 of the operational amplifier chip U1 is connected with the pin 6 of the operational amplifier chip U1 through a capacitor C8, a pin 7 of the operational amplifier chip U1 is connected with the pin 6 of the operational amplifier chip U1 through a capacitor C9 and a resistor R7 which are connected in parallel, and the pin 7 of the operational amplifier chip U1 outputs a sensor output signal S_VOUT through a resistor R8.
Preferably, the level holding circuit includes a field effect transistor Q1, the field effect transistor Q1 is a JEFT transistor, and the model of the field effect transistor Q1 is MMBFJ177LT1P; the grid electrode of the field effect transistor Q1 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal through a resistor R4; the drain electrode of the field effect transistor Q1 is connected with the RE pin of the electrochemical intelligent sensor, and the source electrode of the field effect transistor Q1 is connected with the WE1 pin of the electrochemical intelligent sensor.
Preferably, the analog-to-digital conversion circuit comprises an analog-to-digital converter chip U3 and an MCU chip U4;
the pin 1 of the analog-to-digital converter chip U3 is connected with a SENSOR output signal S_VOUT output by the current-to-voltage circuit, the pin 2 of the analog-to-digital converter chip U3 is grounded, the pin 6 of the analog-to-digital converter chip U3 is connected with a reference voltage REF_1, the pin 6 of the analog-to-digital converter chip U3 is connected with the pin 1 of the analog-to-digital converter chip U3 through a capacitor C11, the pin 5 of the analog-to-digital converter chip U3 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal, the pin 3 of the analog-to-digital converter chip U3 is connected with an I2C1_SCL_EC signal, and the pin 4 of the analog-to-digital converter chip U3 is connected with an I2C1_SDA_EC signal;
the model of the MCU chip U4 is GD32F303CCT6; the pin 42 of the MCU chip U4 is connected with the pin 3 of the analog-to-digital converter chip U3, and the pin 43 of the MCU chip U4 is connected with the pin 4 of the analog-to-digital converter chip U3; pin 45 and pin 46 of MCU chip U4 output SCL_DAC_MCU signal and SDA_DAC_MCU signal, respectively; the pin 12, the pin 13 and the pin 14 of the MCU chip U4 are used as data communication ports, and the pin 12 of the MCU chip U4 is connected with TXD1 signals through a resistor R101; pin 13 of MCU chip U4 connects RXD1 signal through resistance R102, and pin 14 of MCU chip U4 connects DAC_OUT signal.
Preferably, the sensor signal output circuit is an analog voltage output circuit and comprises an operational amplifier U7 and a digital-to-analog conversion chip, namely a DA chip U6; the pin 4 of the DA chip U6 is input with SDA_DAC signals, namely, the pin 4 of the DA chip U6 is connected with the pin 46 of the MCU chip U4 through a resistor R11, the pin 5 of the DA chip U6 is input with SCL_DAC signals, namely, the pin 5 of the DA chip U6 is connected with the pin 45 of the MCU chip U4 through a resistor R109, the pin 2 and the pin 6 of the DA chip U6 are grounded, the pin 3 of the DA chip U6 is respectively grounded through a capacitor C102 and a capacitor C15, the pin 3 of the DA chip U6 is connected with a voltage signal MAN_5V, the pin 1 of the DA chip U6 is connected with the pin 1 of the operational amplifier U7, the pin 3 of the operational amplifier U7 is connected with the pin 4 of the operational amplifier U7, and the operational amplifier U74 outputs analog voltage output signals, namelyThe signal range is 1V-4.8V.
Preferably, the upper cover, the rotary connecting piece, the fixed support and the main shell are all provided with threaded structures, and the upper cover, the rotary connecting piece, the fixed support and the main shell are sequentially connected through threads.
The beneficial effects are that:
(1) The sensor is of an integrated modularized design, is small in structural design and is convenient to use on a vehicle; the mechanical interface is easy to disassemble and assemble, can be installed on a vehicle running dynamically, and can keep long-term reliable running under the condition of unstable machinery;
(2) The sensor supports an online calibration function, and each sensor is placed in a sensitive gas environment to perform response curve calibration before leaving a factory, so that the measurement accuracy of each sensor in working can be ensured;
(3) The sensor provided by the utility model has the advantages that the response output voltage range is set to be 1-4.8V, and the sensor has the advantages that on one hand, when no gas leaks, the output is kept at 1V, which is different from 0V output when equipment fails, so that the sensor is beneficial to judging whether the working state of the sensor is normal, and on the other hand, the full-scale output voltage of 4.8V is compared with the full-scale output voltage of 3.3V, so that the sensor has higher measurement precision under the condition of the same measuring range.
Drawings
FIG. 1 is an exploded view of a sensor of the present utility model;
FIG. 2 is a top view of the sensor of the present utility model;
FIG. 3 is a side view of a sensor of the present utility model;
FIG. 4 is a block diagram of the overall circuit design of the present utility model;
FIG. 5 is a block diagram of a sensor data processing portion of the present utility model;
FIG. 6 is a schematic circuit diagram of an electrochemical smart sensor of the present utility model;
FIG. 7 is a schematic diagram of a data processing board circuit of the present utility model;
FIG. 8 is a schematic circuit diagram of an on-board analog-to-digital conversion circuit of the present utility model;
fig. 9 is a schematic circuit diagram of the sensor signal output circuit on the sensor board of the present utility model.
Detailed Description
A propellant gas concentration monitoring sensor according to the present utility model will be further described and illustrated with reference to the accompanying drawings.
As shown in fig. 1 to 3, a propellant gas concentration monitoring sensor comprises: a main casing 1, a gas concentration detection unit 2, a signal processing unit 3, a fixed bracket 4, a rotary connector 5, an upper cover 6, a front end sealing cover 7 and an electric connector 8; one side of the fixed support 4 is fixed with an upper cover 6 through a rotary connecting piece 5, the other side of the fixed support is connected with one side of the main shell 1, and the other side of the main shell 1 is fixed with a front end sealing cover 7;
the electric connector 8, the signal processing unit 3 and the gas concentration detection unit 2 are sequentially connected, the electric connector 8 is arranged in the hollow cavity of the rotary connector 5, and an output interface of the electric connector 8 is led out from the upper cover 6 and is used for outputting the detection result of the propellant gas concentration monitoring sensor; the input end of the electric connector 8 is connected with the signal processing unit 3, a gas concentration detection unit 2 and the signal processing unit 3 which are connected are fixedly arranged in a hollow cavity of the main shell 1, the gas concentration detection unit 2 is an electrochemical intelligent sensor, and a gas concentration signal detected by the gas concentration detection unit 2 is processed by the signal processing unit 3 and then is output through the electric connector 8; the gas concentration detection unit 2 is close to the front end sealing cover 7 for detecting gas concentration information when the front end sealing cover 7 is opened for use.
The electric connector 8 is a round electric connector, the model of the electric connector is Y8B-7ZJBM, and the definition of the contact is shown in Table 1.
TABLE 1 output contact definition
The assembly process of the utility model is as follows: the signal processing unit 3 and the gas concentration detection unit 2 are connected with the electric connector 8 after being welded, and are placed in the hollow cavity of the main shell 1, the upper cover 6, the rotary connecting piece 5, the fixed support 4 and the main shell 1 are screwed together through threads, the output port of the electric connector 8 leaks from the upper cover 6, and the front end sealing cover 7 is fixed on the main shell 1 through manual screwing.
The application process of the utility model is as follows: before use, the front end sealing cover 7 is closed, the propellant is typically unsymmetrical dimethylhydrazine or dinitrogen tetroxide, when the propellant is detected in gas concentration, the front end sealing cover 7 is opened, propellant gas enters the propellant gas concentration monitoring sensor, the gas concentration detection unit 2 detects the concentration of the propellant gas, and the output analog signal is processed by the signal processing unit 3 and then is output through the electric connector 8, so that the detection of the gas concentration is completed.
The upper cover 6, the rotary connecting piece 5, the fixed support 4 and the main shell 1 are all provided with threaded structures, and the upper cover 6, the rotary connecting piece 5, the fixed support 4 and the main shell 1 are sequentially in threaded connection. The upper cover 6, the rotary connecting piece 5, the fixed support 4 and the main shell 1 are all made of metal materials, and the front end sealing cover 7 is made of non-metal materials such as ethylene propylene rubber and the like.
The fixing support 4 is provided with mounting unthreaded holes around, and the fixing support 4 adopts circular arc transition to prevent stress concentration.
The sensor is of an integrated modularized design, is small in structural design and is convenient to use on a vehicle; the mechanical interface is easy to disassemble and assemble, can be installed on a vehicle running dynamically, and can keep long-term reliable running under the condition of unstable machinery.
As shown in fig. 4 to 7, the signal processing unit 3 comprises a sensor board and a data processing board which are connected, wherein an analog-to-digital conversion circuit, a sensor signal output circuit and a power supply circuit are arranged on the sensor board; the data processing board is provided with an electrochemical sensor, a potentiostat circuit, a level holding circuit and a current-to-voltage circuit; the power supply circuit is used for supplying power to the potentiostat circuit, the level holding circuit, the current-to-voltage circuit and the analog-to-digital conversion circuit; the electrochemical sensor is connected with the potentiostat circuit, the level holding circuit and the current-to-voltage circuit, the analog-to-digital conversion circuit and the sensor signal output circuit are sequentially connected.
The model of the electrochemical intelligent sensor is NO2-3E-40 (4 nd); the pin 1 of the electrochemical intelligent sensor is a CE pin, which is used as a counter electrode (also called a counter electrode and an auxiliary electrode) of the electrochemical intelligent sensor, the pin 2 is a WE1 pin, which is used as a working electrode (also called a to-be-detected electrode, a detection electrode and an indication electrode) of the electrochemical intelligent sensor, and the pin 3 is an RE pin, which is used as a reference electrode of the electrochemical intelligent sensor; the working principle of the electrochemical intelligent sensor is as follows: oxidizing or reducing the target gas at the working electrode WE1, generating a current proportional to the gas concentration, the current being supplied to the sensor through the counter electrode CE; the reference electrode RE and the working electrode WE1 are kept at a fixed potential;
the constant potential rectifier circuit and the current-to-voltage circuit share an operational amplifier chip U1; the operational amplifier chip U1 includes two parts: U1-A in the potentiostat circuit and U1-B in the current-to-voltage circuit; the model of the operational amplifier chip U1 is SGM8621/MSOP-8;
the potentiostat circuit comprises an operational amplifier chip U1, wherein a pin 2 of the operational amplifier chip U1 is connected with a RE pin of the electrochemical intelligent sensor through a resistor R3 and a resistor R2, a pin 3 of the operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R10, and a pin 2 of the operational amplifier chip U1 is connected with a pin 3 of the operational amplifier chip U1 through a capacitor C2; the pin 1 of the operational amplifier chip U1 is connected with the CE pin of the electrochemical intelligent sensor through a resistor R1, and the pin 1 of the operational amplifier chip U1 is connected with the pin 2 of the operational amplifier chip U1 through a capacitor C1 and a resistor R3; the constant potential rectifier circuit adopts a negative feedback circuit, and the level of the CE pin is consistent with the level of the RE pin through a negative feedback mechanism, so that the reference voltage REF_1 is approached;
the level holding circuit comprises a field effect transistor Q1, wherein the field effect transistor Q1 is a JEFT (jet field effect transistor) and the model of the JEFT is MMBFJ177LT1P; the grid electrode of the field effect transistor Q1 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal through a resistor R4; the drain electrode of the field effect transistor Q1 is connected with the RE pin of the electrochemical intelligent sensor, and the source electrode of the field effect transistor Q1 is connected with the WE1 pin of the electrochemical intelligent sensor. Because the sensor needs a great deal of time to wait for the negative feedback adjustment to be finished every time the sensor enters a working state, the reference electrode RE and the working electrode WE1 are short-circuited when not in use to reduce the time of the negative feedback adjustment, and therefore, in the level holding circuit, the reference electrode RE and the working electrode WE1 are short-circuited together under the condition of power failure through the field effect transistor Q1, the working electrode is ensured to keep the same potential as the reference electrode when the circuit is closed, and the reference electrode RE and the working electrode WE1 are short-circuited when power is supplied.
In the current-to-voltage circuit, a pin 5 of an operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R9, a pin 6 of the operational amplifier chip U1 is connected with a WE1 pin of an electrochemical intelligent sensor through a resistor R5, a pin 5 of the operational amplifier chip U1 is connected with a pin 6 of the operational amplifier chip U1 through a capacitor C8, a pin 7 of the operational amplifier chip U1 is connected with a pin 6 of the operational amplifier chip U1 through a capacitor C9 and a resistor R7 which are connected in parallel, and a pin 7 of the operational amplifier chip U1 outputs a sensor output signal S_VOUT through a resistor R8; in the current-to-voltage circuit, the characteristics of large input impedance and small output impedance of the operational amplifier are utilized to convert current into voltage and regulate the value of the voltage.
The working process among the electrochemical sensor, the potentiostat circuit and the level holding circuit is as follows: for a three-electrode electrochemical sensor, the main purpose is to maintain the voltage between the reference electrode RE and the working electrode WE1 to control the electrochemical reaction and output an output signal proportional to the generated current. When the electrochemical sensor responds to the target gas, an electrical current is generated that is proportional to the gas concentration. This current must be supplied to the electrochemical sensor through the counter electrode CE where the opposite redox reaction takes place, the working electrode WE1 completes the circuit, allowing the potential of the counter electrode CE to float. When gas is detected, the cell current rises and the counter electrode CE is polarized with respect to the reference. The potential of the counter electrode CE is not critical as long as the circuit can provide sufficient voltage and current to maintain the correct potential of the working electrode WE 1. The sensor working electrode WE1 outputs a weak current, and the weak current is reflected on a resistor R7 through a current-to-voltage circuit to generate an output voltage relative to the ground GND, so that a current signal is converted into a voltage signal, and the voltage signal is filtered through a filter, namely a capacitor C9, so that useless alternating current interference signals are filtered, and a stable voltage value, namely S-VOUT, is obtained.
The reference voltage REF_1 is generated through a reference voltage circuit, wherein the reference voltage circuit comprises a reference voltage chip U2, and the model of the reference voltage chip U2 is SPX3819; the pin 1 of the reference voltage chip U2 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal; the pin 1 of the reference voltage chip U2 is connected with the pin 3 of the reference voltage chip U2 through a capacitor C5, and the pin 3 of the reference voltage chip U2 is connected with the pin 2 of the reference voltage chip U2 through a capacitor C6; pin 3 of the reference voltage chip U2 is grounded, and pin 2 of the reference voltage chip U2 outputs a reference voltage REF_1.
As shown in fig. 8, the analog-to-digital conversion circuit includes an analog-to-digital converter chip U3 and an MCU chip U4;
the model of the analog-to-digital converter chip U3 is CS1237/SOT-23-6/ADI; high-precision and low-power consumption analog-digital conversion, one path of differential input channel, built-in temperature sensor and high-precision oscillator, 24-bit non-missing code and in-band short function. The MCU may communicate with the CS1237 via the 2-wire SPI interfaces SCLK, DRDY, configure it, e.g., channel selection, PGA selection, output number rate selection, etc.
The pin 1 of the analog-to-digital converter chip U3 is connected with a SENSOR output signal S_VOUT output by the current-to-voltage circuit, the pin 2 of the analog-to-digital converter chip U3 is grounded, the pin 6 of the analog-to-digital converter chip U3 is connected with a reference voltage REF_1, the pin 6 of the analog-to-digital converter chip U3 is connected with the pin 1 of the analog-to-digital converter chip U3 through a capacitor C11, the pin 5 of the analog-to-digital converter chip U3 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal, the pin 3 of the analog-to-digital converter chip U3 is connected with an I2C1_SCL_EC signal, and the pin 4 of the analog-to-digital converter chip U3 is connected with an I2C1_SDA_EC signal;
the model of the MCU chip U4 is GD32F303CCT6, and the chip has an ADC function, so that the MCU circuit is designed to finish functions of AD sampling, data calibration, analog output control and the like; has the operating frequency of 32 bits 108Mz, can be over-frequency to 120MHz, can improve the performance by more than 30 percent, compared with chips of the same type of STM32 series, it has 128 KFDASH, FLASH zero waiting, 96KBSRAM, power supply range 2.6-3.6V, the working temperature is-40-85 ℃, ARM Cortex-M3 new kernel R2p1 is adopted, and the performance is stable and reliable;
the pin 42 of the MCU chip U4 is connected with the pin 3 of the analog-to-digital converter chip U3, and the pin 43 of the MCU chip U4 is connected with the pin 4 of the analog-to-digital converter chip U3; pin 45 and pin 46 of MCU chip U4 output SCL_DAC_MCU signal and SDA_DAC_MCU signal, respectively; the pin 12, the pin 13 and the pin 14 of the MCU chip U4 are used as data communication ports, and the pin 12 of the MCU chip U4 is connected with TXD1 signals through a resistor R101; pin 13 of MCU chip U4 connects RXD1 signal through resistor R102, pin 14 of MCU chip U4 connects DAC_OUT signal; the TXD1 pin is a serial port output end of the MCU chip U4 and is used for outputting digital measurement or debugging information; the RXD1 pin is a serial port input end of the MCU chip U4, and the MCU chip U4 receives a control command or calibration information through the two pins; the DAC_OUT pin is an analog voltage output pin for outputting analog measurements of the sensor.
As shown in fig. 9, the sensor signal output circuit is an analog voltage output circuit, and comprises an operational amplifier U7 and a digital-to-analog conversion chip, namely a DA chip U6; the model of the operational amplifier U7 is SGM8621/MSOP-8, and the model of the digital-to-analog conversion chip is MCP4725/SOT23-6;
the pin 4 of the DA chip U6 is input with SDA_DAC signals, namely, the pin 4 of the DA chip U6 is connected with the pin 46 of the MCU chip U4 through a resistor R11, the pin 5 of the DA chip U6 is input with SCL_DAC signals, namely, the pin 5 of the DA chip U6 is connected with the pin 45 of the MCU chip U4 through a resistor R109, the pin 2 and the pin 6 of the DA chip U6 are grounded, the pin 3 of the DA chip U6 is respectively grounded through a capacitor C102 and a capacitor C15, the pin 3 of the DA chip U6 is connected with a voltage signal MAN_5V, the pin 1 of the DA chip U6 is connected with the pin 1 of the operational amplifier U7, the pin 3 of the operational amplifier U7 is connected with the pin 4 of the operational amplifier U7, and the pin 4 of the operational amplifier U7 outputs analog voltage output signals, namelyA signal; the sensor signal output circuit realizes the conversion of sensor data into analog 1V-4.8V direct current voltage output. Detected gas concentration->The higher the output voltage +>The higher the corresponding relation is basically in accordance with a third-order linear curve, the expression is as follows, wherein the a, b, c, d four parameters are calibrated in each sensor calibration test: />。
The sensor supports an online calibration function, and each sensor is placed in a sensitive gas environment to perform response curve calibration before leaving a factory, so that the measurement accuracy of each sensor in working can be ensured;
the sensor provided by the utility model has the advantages that the response output voltage range is set to be 1-4.8V, and the sensor has the advantages that on one hand, when no gas leaks, the output is kept at 1V, which is different from 0V output when equipment fails, so that the sensor is beneficial to judging whether the working state of the sensor is normal, and on the other hand, the full-scale output voltage of 4.8V is compared with the full-scale output voltage of 3.3V, so that the sensor has higher measurement precision under the condition of the same measuring range.
The foregoing is only a preferred embodiment of the utility model, it being noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the present utility model, and such modifications and adaptations are intended to be comprehended within the scope of the utility model.

Claims (8)

1. A propellant gas concentration monitoring sensor, comprising: the device comprises a main shell, a gas concentration detection unit, a signal processing unit, a fixed bracket, a rotary connecting piece, an upper cover, a front end sealing cover and an electric connector; one side of the fixed support is fixed with the upper cover through the rotary connecting piece, the other side of the fixed support is connected with one side of the main shell, and the other side of the main shell is fixed with the front end sealing cover;
the electric connector, the signal processing unit and the gas concentration detection unit are sequentially connected, the electric connector is arranged in the hollow cavity of the rotary connecting piece, and an output interface of the electric connector is led out from the upper cover and is used for outputting the detection result of the propellant gas concentration monitoring sensor; the input end of the electric connector is connected with the signal processing unit, a gas concentration detection unit and a signal processing unit which are connected are fixedly arranged in a hollow cavity of the main shell, the gas concentration detection unit is an electrochemical intelligent sensor, and a gas concentration signal detected by the gas concentration detection unit is processed by the signal processing unit and then is output through the electric connector; the gas concentration detection unit is close to the front end sealing cover and is used for detecting gas concentration information when the front end sealing cover is opened for use.
2. A propellant gas concentration monitoring sensor according to claim 1, wherein: the signal processing unit comprises a sensor board and a data processing board which are connected, wherein an analog-to-digital conversion circuit, a sensor signal output circuit and a power supply circuit are arranged on the sensor board; the data processing board is provided with an electrochemical sensor, a potentiostat circuit, a level holding circuit and a current-to-voltage circuit; the power supply circuit is used for supplying power to the potentiostat circuit, the level holding circuit, the current-to-voltage circuit and the analog-to-digital conversion circuit; the electrochemical sensor is connected with the potentiostat circuit, the level holding circuit and the current-to-voltage circuit, the analog-to-digital conversion circuit and the sensor signal output circuit are sequentially connected.
3. A propellant gas concentration monitoring sensor according to claim 2, characterized in that: the pin 1 of the electrochemical intelligent sensor is a CE pin, the CE pin is used as a counter electrode of the electrochemical intelligent sensor, the pin 2 is a WE1 pin, the CE pin is used as a working electrode of the electrochemical intelligent sensor, and the pin 3 is a RE pin, and the CE pin is used as a reference electrode of the electrochemical intelligent sensor.
4. A propellant gas concentration monitoring sensor according to claim 3, characterized in that: the constant potential rectifier circuit and the current-to-voltage circuit share an operational amplifier chip U1; the operational amplifier chip U1 includes two parts: U1-A in the potentiostat circuit and U1-B in the current-to-voltage circuit;
in the potentiostat circuit, a pin 2 of an operational amplifier chip U1 is connected with a RE pin of an electrochemical intelligent sensor through a resistor R3 and a resistor R2, a pin 3 of the operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R10, and a pin 2 of the operational amplifier chip U1 is connected with a pin 3 of the operational amplifier chip U1 through a capacitor C2; the pin 1 of the operational amplifier chip U1 is connected with the CE pin of the electrochemical intelligent sensor through a resistor R1, and the pin 1 of the operational amplifier chip U1 is connected with the pin 2 of the operational amplifier chip U1 through a capacitor C1 and a resistor R3;
in the current-to-voltage circuit, a pin 5 of an operational amplifier chip U1 is connected with a reference voltage REF_1 through a resistor R9, a pin 6 of the operational amplifier chip U1 is connected with a WE1 pin of an electrochemical intelligent sensor through the resistor R5, the pin 5 of the operational amplifier chip U1 is connected with the pin 6 of the operational amplifier chip U1 through a capacitor C8, a pin 7 of the operational amplifier chip U1 is connected with the pin 6 of the operational amplifier chip U1 through a capacitor C9 and a resistor R7 which are connected in parallel, and the pin 7 of the operational amplifier chip U1 outputs a sensor output signal S_VOUT through a resistor R8.
5. A propellant gas concentration monitoring sensor according to claim 2, characterized in that: the level holding circuit comprises a field effect transistor Q1, wherein the field effect transistor Q1 is a JEFT (jet field effect transistor) and the model of the JEFT is MMBFJ177LT1P; the grid electrode of the field effect transistor Q1 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal through a resistor R4; the drain electrode of the field effect transistor Q1 is connected with the RE pin of the electrochemical intelligent sensor, and the source electrode of the field effect transistor Q1 is connected with the WE1 pin of the electrochemical intelligent sensor.
6. A propellant gas concentration monitoring sensor according to claim 2, characterized in that: the analog-to-digital conversion circuit comprises an analog-to-digital converter chip U3 and an MCU chip U4;
the pin 1 of the analog-to-digital converter chip U3 is connected with a SENSOR output signal S_VOUT output by the current-to-voltage circuit, the pin 2 of the analog-to-digital converter chip U3 is grounded, the pin 6 of the analog-to-digital converter chip U3 is connected with a reference voltage REF_1, the pin 6 of the analog-to-digital converter chip U3 is connected with the pin 1 of the analog-to-digital converter chip U3 through a capacitor C11, the pin 5 of the analog-to-digital converter chip U3 is connected with a SENSOR voltage signal, namely a 3_3-VCC-SENSOR signal, the pin 3 of the analog-to-digital converter chip U3 is connected with an I2C1_SCL_EC signal, and the pin 4 of the analog-to-digital converter chip U3 is connected with an I2C1_SDA_EC signal;
the model of the MCU chip U4 is GD32F303CCT6; the pin 42 of the MCU chip U4 is connected with the pin 3 of the analog-to-digital converter chip U3, and the pin 43 of the MCU chip U4 is connected with the pin 4 of the analog-to-digital converter chip U3; pin 45 and pin 46 of MCU chip U4 output SCL_DAC_MCU signal and SDA_DAC_MCU signal, respectively; the pin 12, the pin 13 and the pin 14 of the MCU chip U4 are used as data communication ports, and the pin 12 of the MCU chip U4 is connected with TXD1 signals through a resistor R101; pin 13 of MCU chip U4 connects RXD1 signal through resistance R102, and pin 14 of MCU chip U4 connects DAC_OUT signal.
7. Root of Chinese characterA propellant gas concentration monitoring sensor as claimed in claim 2, wherein: the sensor signal output circuit is an analog voltage output circuit and comprises an operational amplifier U7 and a digital-to-analog conversion chip, namely a DA chip U6; the pin 4 of the DA chip U6 is input with SDA_DAC signals, namely, the pin 4 of the DA chip U6 is connected with the pin 46 of the MCU chip U4 through a resistor R11, the pin 5 of the DA chip U6 is input with SCL_DAC signals, namely, the pin 5 of the DA chip U6 is connected with the pin 45 of the MCU chip U4 through a resistor R109, the pin 2 and the pin 6 of the DA chip U6 are grounded, the pin 3 of the DA chip U6 is respectively grounded through a capacitor C102 and a capacitor C15, the pin 3 of the DA chip U6 is connected with a voltage signal MAN_5V, the pin 1 of the DA chip U6 is connected with the pin 1 of the operational amplifier U7, the pin 3 of the operational amplifier U7 is connected with the pin 4 of the operational amplifier U7, and the operational amplifier U74 outputs analog voltage output signals, namelyThe signal range is 1V-4.8V.
8. A propellant gas concentration monitoring sensor according to claim 1, wherein: the upper cover, the rotary connecting piece, the fixed support and the main shell are all provided with threaded structures, and the upper cover, the rotary connecting piece, the fixed support and the main shell are sequentially connected through threads.
CN202420025260.3U 2024-01-05 2024-01-05 Propellant gas concentration monitoring sensor Active CN220490731U (en)

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Application Number Priority Date Filing Date Title
CN202420025260.3U CN220490731U (en) 2024-01-05 2024-01-05 Propellant gas concentration monitoring sensor

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Application Number Priority Date Filing Date Title
CN202420025260.3U CN220490731U (en) 2024-01-05 2024-01-05 Propellant gas concentration monitoring sensor

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