CN116642939A - Networked double-channel electrochemical gas detection circuit - Google Patents

Abstract

The invention discloses a networked dual-channel electrochemical gas detection circuit, belonging to the related technical field of electrochemical gas detection, which includes a dual-channel gas detection module, a high-precision power supply module, a digital rheostat module, an analog-to-digital conversion module, and the An Ethernet controller connected to the analog-to-digital conversion module, wherein the Ethernet controller and the upper computer are connected by a network cable, optical fiber or wirelessly, and the analog-to-digital conversion module communicates with the Ethernet controller and connects the The analog signal collected by the gas sensor in the dual-channel gas detection module is converted into a digital signal output, which solves the problem of the single detection variety of ordinary gas detectors, slow signal transmission speed, easy to be interfered, many types of input cards, large quantities, and the need to lay a large number of Cables and bridges, and there are problems such as signal attenuation and delay, which have changed the traditional gas detection and control networking mode.

Description

A networked dual-channel electrochemical gas detection circuit

technical field

The invention relates to the technical field of electrochemical gas detection, in particular to a networked dual-channel electrochemical gas detection circuit.

Background technique

Existing gas detection instruments can only measure a single gas, and use 4~20mA signal connection or RS485 signal connection. When a variety of flammable and toxic gases are involved in the scene, multiple gas detection instruments need to be installed, resulting in a wide variety of on-site gas detection devices. When using 4~20mA signal connection, there are many signal lines required for transmission, and there are unfavorable factors such as long distance, poor interference ability, and difficult construction; when using RS485 signal connection, the signal delay is relatively long, which cannot reflect the scene in real time Changes in the gas environment.

With the development of industry and the advancement of science and technology, the requirements for control systems in industrial sites are getting higher and higher. The large-scale and high-integration effects of modern production environments require terminal devices in different areas to be able to collect and monitor analog signals on site. Output, the existing remote I/O modules have been unable to meet the requirements of controlling field devices with a long distance.

In addition, special workplaces such as chemical companies have very strict requirements on control circuits. The on-site control circuits are all explosion-proof or intrinsically safe circuits. All external gas detectors must be connected to the gas detection controller with separate cables. Many disadvantages: 1. There are many cables and bridges on site, large installation engineering, high cost, and potential safety hazards; 2. Each signal requires a photoelectric isolation safety barrier, which increases the point of failure; 3. Interference between cables affects the operation of equipment The stability is affected, and maintenance is difficult.

Contents of the invention

The present invention provides a networked dual-channel electrochemical gas detection circuit, aiming to solve the above-mentioned technical defects.

The concrete technical scheme that the present invention provides is as follows:

A networked dual-channel electrochemical gas detection circuit provided by the present invention includes a dual-channel gas detection module, a high-precision power supply module connected to the dual-channel gas detection module, and a digital digital sensor connected to the dual-channel gas detection module. A rheostat module, an analog-to-digital conversion module connected to the digital rheostat module and the dual-channel gas detection module, and an Ethernet controller connected to the analog-to-digital conversion module, wherein the Ethernet controller and the upper computer The analog-to-digital conversion module communicates with the Ethernet controller and converts the analog signal collected by the gas sensor in the dual-channel gas detection module into a digital signal for output.

Optionally, the dual-channel gas detection module includes a precision operational amplifier U6, a resistor R2 connected to the positive input terminal of the precision operational amplifier U6, a dual chemical gas sensor U7 connected to the output terminal of the precision operational amplifier U6, a resistor R1, Resistor R3, capacitor C1, and capacitor C2, wherein resistor R1 and capacitor C1 are connected in parallel to the negative input terminal of precision operational amplifier U6, and resistor R1 and resistor R3 are connected in parallel to capacitor C2 in series.

Optionally, the precision operational amplifier U6 adopts the low-noise precision amplifier ADA4528-1ARMZ, and the dual chemical gas sensor U7 adopts the COH-A2 dual-channel gas detection sensor.

Optionally, the high-precision power supply module includes a DC stabilized power supply U4 and a DC stabilized power supply U5 connected to each other, wherein the DC stabilized power supply U4 adopts an ADP7102 power supply module, and the DC stabilized power supply U5 adopts an ADR3412 power supply module. The piezoelectric power supply U4 is used to convert the 5V DC power supply into a 3.3V DC power supply, and the DC stabilized power supply U5 is used to convert the 3.3V DC power supply into a 1.2V DC power supply.

Optionally, the digital rheostat module includes a precision amplifier U11, a precision amplifier U12, a digital rheostat U1, a digital resistor U10, a P-channel switch field effect transistor U3, a P-channel switch field effect transistor U9, a resistor R4, and a resistor R8 , resistor R9, capacitor C3, capacitor C5, resistor R7, resistor R10, resistor R11, resistor R12, capacitor C6, resistor R13 and capacitor C4.

Optionally, precision amplifier U11 and precision amplifier U12 both use low-noise precision amplifier ADA4528-1ARMZ, digital rheostat U1 and digital resistor U10 both use AD5270 digital rheostat, P-channel switch FET U3 and P-channel switch FET Tube U9 adopts MMBFJ270 field effect tube.

Optionally, the AD7798 analog-to-digital converter U2 is used as the analog-to-digital conversion module, and the W5500 Ethernet controller is used as the Ethernet controller.

Optionally, the first pin TXN of the network communication port of the Ethernet controller is connected to a resistor R17, the second pin TXP of the network communication port of the Ethernet controller is connected to a resistor R18, and the network communication port of the Ethernet controller The 5th pin RXP and the 6th pin RXN of the communication port are respectively connected to the resistor R19, the resistor R20, and the 3rd and 6th ports of the RJ-45. The tenth pin EXRES1 of the Ethernet controller is connected to the resistor R21, the other end of the resistor R21 is connected to GND, the seventh pin RSTN of the Ethernet controller is connected to the RESET port of the switch as a reset switch, and the other end of the switch RESET is connected to GND.

Optionally, the resistors R6, R7, and R16 are pull-up resistors, and the resistors R6, R7, and R16 are respectively connected to the 38th, 39th, 40th, 41st, 42nd, 43rd, 44th, 45th of the Ethernet controller. Pin RSV, PMODE port, the other end is connected to GND.

Optionally, the clock circuit of the Ethernet controller is composed of a capacitor C23, a capacitor C22, a resistor R22, and a crystal oscillator X1, and the capacitor C23, capacitor C22, resistor R22, and crystal oscillator X1 are connected to the 31st pin X0 of the Ethernet controller. , the 30th pin XL/CLKIN and provide the clock signal for the Ethernet controller.

The present invention has the following beneficial technical effects:

An embodiment of the present invention provides a networked dual-channel electrochemical gas detection circuit including a dual-channel gas detection module, a high-precision power supply module connected to the dual-channel gas detection module, and a A digital rheostat module, an analog-to-digital conversion module connected to the digital rheostat module and the dual-channel gas detection module, and an Ethernet controller connected to the analog-to-digital conversion module, wherein the Ethernet controller and the upper computer Connected by network cable, optical fiber or wireless, the analog-to-digital conversion module communicates with the Ethernet controller and converts the analog signal collected by the gas sensor in the dual-channel gas detection module into a digital signal output, which solves the problem of Ordinary gas detectors have a single detection variety, slow signal transmission speed, easy to be interfered, many types of input cards, a large number, a large number of cables and bridges need to be laid, and there are problems such as signal attenuation and delay, which has changed the traditional gas detector. Detect and control networking mode.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is a connection schematic diagram of a networked dual-channel electrochemical gas detection circuit according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a networked dual-channel electrochemical gas detection circuit according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

A networked dual-channel electrochemical gas detection circuit according to an embodiment of the present invention will be described in detail below with reference to FIGS. —20mA and RS485 communication speed is slow, easy to be interfered, there are many types and quantities of output cards, a large number of cables and bridges need to be laid, and there are technical problems of signal attenuation and delay.

Referring to Figures 1 to 2, a networked dual-channel electrochemical gas detection circuit provided by an embodiment of the present invention includes a dual-channel gas detection module, a high-precision power supply module connected to the dual-channel gas detection module, and a dual-channel gas detection module. A digital rheostat module connected to the gas detection modules, an analog-to-digital conversion module connected to the digital rheostat module and a dual-channel gas detection module, and an Ethernet controller connected to the analog-to-digital conversion module, wherein, as shown in Figure 1, the Ethernet The controller and the upper computer are connected by network cable, optical fiber or wireless, and the analog-to-digital conversion module communicates with the Ethernet controller and converts the analog signal collected by the gas sensor or gas detector in the dual-channel gas detection module into a digital signal output.

A networked dual-channel electrochemical gas detection circuit provided by the embodiment of the present invention receives the detection signal of the gas sensor through the remote network module, and transmits it to the host computer in real time, and at the same time, the signal transmission mode between the host computer and the host computer is network transmission; and Adopt high-precision analog-to-digital conversion circuit, high-precision analog-to-digital conversion circuit, provide monitoring function through the network cable network, use the network to monitor the current node, and effectively manage I/O equipment at any remote location. A networked dual-channel electrochemical gas detection circuit provided by the embodiment of the present invention has strong anti-interference ability, can simplify the input card parts in the DCS cabinet, greatly reduce the consumption of cables, and can save a lot of construction costs and hardware costs. Unlimited number of networks, the use of this system is very convenient and flexible, only need to install the device of the present invention in the place where it is needed, and connect with the host computer with a network cable or optical fiber to complete the connection. It has strong versatility, high precision, stability, and Strong interference ability.

Referring to Figure 2, the dual-channel gas detection module includes a precision operational amplifier U6, a resistor R2 connected to the positive input of the precision operational amplifier U6, a dual chemical gas sensor U7 connected to the output of the precision operational amplifier U6, a resistor R1, Resistor R3, capacitor C1, and capacitor C2, wherein resistor R1 and capacitor C1 are connected in parallel to the negative input terminal of precision operational amplifier U6, and resistor R1 and resistor R3 are connected in parallel to capacitor C2 in series. Among them, the precision operational amplifier U6 uses a low-noise precision amplifier ADA4528-1ARMZ, and the dual chemical gas sensor U7 uses a COH-A2 dual-channel gas detection sensor.

As shown in Figure 2, the high-precision power supply module includes DC regulated power supply U4 and DC regulated power supply U5 that are connected to each other. Among them, the DC regulated power supply U4 uses the ADP7102 power module, and the DC regulated power supply U5 uses the ADR3412 power module. The piezoelectric power supply U4 is used to convert the 5V DC power supply into a 3.3V DC power supply, and the DC stabilized power supply U5 is used to convert the 3.3V DC power supply into a 1.2V DC power supply.

As shown in Figure 2, the digital rheostat module includes a precision amplifier U11, a precision amplifier U12, a digital rheostat U1, a digital resistor U10, a P-channel switch field effect transistor U3, a P-channel switch field effect transistor U9, a resistor R4, and a resistor R8 , resistor R9, capacitor C3, capacitor C5, resistor R7, resistor R10, resistor R11, resistor R12, capacitor C6, resistor R13 and capacitor C4. Both the precision amplifier U11 and the precision amplifier U12 use the low-noise precision amplifier ADA4528-1ARMZ, the digital varistor U1 and the digital resistor U10 both use the AD5270 digital varistor, the P-channel switch FET U3 and the P-channel switch FET U9 both use MMBFJ270 FET.

Referring to Fig. 2, the analog-to-digital conversion module adopts AD7798 analog-to-digital converter U2, and the Ethernet controller adopts W5500 Ethernet controller. The first pin TXN of the network communication port of the Ethernet controller is connected to resistor R17, the second pin TXP of the network communication port of the Ethernet controller is connected to resistor R18, and the fifth pin of the network communication port of the Ethernet controller RXP and pin 6 RXN are respectively connected to resistor R19, resistor R20, ports 3 and 6 of RJ-45, the other end of resistor R19 and resistor R20 are connected to capacitor C21 and power supply VCC, the other end of capacitor C21 is connected to GND, the Ethernet controller The tenth pin EXRES1 is connected to the resistor R21, the other end of the resistor R21 is connected to GND, the seventh pin RSTN of the Ethernet controller is connected to the switch RESET port as a reset switch, and the other end of the switch RESET is connected to GND.

Referring to Figure 2, resistor R6, resistor R7, and resistor R16 are pull-up resistors, and resistor R6, resistor R7, and resistor R16 are respectively connected to the 38th, 39th, 40th, 41, 42, 43, 44th of the Ethernet controller. , 45-pin RSV, PMODE port, the other end is connected to GND. The clock circuit of the Ethernet controller is composed of a capacitor C23, a capacitor C22, a resistor R22, and a crystal oscillator X1. The capacitor C23, capacitor C22, resistor R22, and crystal oscillator X1 are connected to the 31st pin XO and the 30th pin XL/ CLKIN and provides a clock signal for the Ethernet controller. The 35th pin MOSI of the SPI communication port of the Ethernet controller W5500, the 34th pin MOSO, the 33rd pin SCLK port, and the 8th and 9th pins of the AD5755 analog output controller.

Referring to Figure 2, the filter capacitor connected to the digital-to-analog conversion module, at least one inductor connected to the digital-to-analog conversion module, and at least one diode connected to the digital-to-analog conversion module cooperate with each other to form an analog output module circuit, and the resistance R1 is connected to the 2nd pin of ADA4528 - IN port, resistor R2 is connected to the 3rd pin of ADA4528 + IN port, 3.3.V power supply is connected to the 7th pin of ADA4528 + V port, capacitor C1 is connected to the 2nd pin of ADA4528 - IN port , the 6th pin OUT port. The capacitors C1 and C2 are connected to the COH-A2 pin CE, and the capacitor C2, the resistor R1 and the resistor R3 are connected at one end. On R3COH-A2 pin RE, COH-A2 pin RE is connected to MMBFJ270 pin D, resistor R3 is connected to MMBFJ270 pin D, OH-A2 pin H2S, resistor R11 is connected to one of MMBFJ270 pin S, COH - A2 pin CO and resistor R4 are connected to the other MMBFJ270 pin S.

Referring to Figure 2, resistor R11 is connected to ADA4528 pin -IN, resistor R4 is connected to ADA4528 pin -IN, and AD5270 pin W, resistor R11 is connected to ADA4528 pin -IN, and AD5270 pin W; Capacitor C5 is connected to ADA4528 pin -IN and is connected to AD5270 pin A; capacitor C6 is connected to ADA4528 pin -IN and is connected to AD5270 pin A. Capacitor C5 is connected to ADA4528 pin out, capacitor C6 is connected to ADA4528 pin out; resistor R8 is connected to 1.2V power supply, resistor R8 is connected to ADA4528 pin +IN; resistor R8 is connected to ADA4528 pin +IN; resistor R10 is connected to 1.2 V power supply is connected, resistor R10 is connected to ADA4528 pin +IN; resistor R9 is connected to ADA4528 pin out, resistor R13 is connected to ADA4528 pin out, resistor R9 is connected to C3, resistor R13 is connected to C4, resistor R9 is connected to AD7798 pin AIN1 (+) is connected, resistor R13 is connected to AD7798 pin AIN2 (+); capacitor C3 is connected to AD7798 pin AIN1 (+), capacitor C4 is connected to AD7798 pin AIN2 (+); capacitor C3 is connected to ground, and capacitor C4 connected to ground.

Referring to Figure 2, the DC regulated power supply U4 is used to convert the 5V DC power supply into a 3.3V DC power supply, and is connected to the AD7798 pin AVDD\DVDD. The DC regulated power supply U5 is used to convert the 3.3V DC power supply into a 1.2V DC power supply, and is connected to the AD7798 pins AIN1(-), AIN2(-), AIN3(-), REFIN+. The embodiment of the present invention provides a networked dual-channel electrochemical gas detection circuit. During operation, the gas detection signal is directly communicated with the host computer through the network, optical fiber, etc. through analog-to-digital conversion, which can reduce many intermediate links. Can be installed directly in the gas detector.

As shown in Figure 2, the DC regulated power supply U4 converts the 5V DC power supply into 3.3V DC power supply, which is supplied to U3, U9, U1, U10, U6, and U11 to provide them with a DC regulated power supply; the DC regulated power supply U5 converts 3.3V DC power supply V DC power is converted into 1.2V DC power, which is supplied to U6, U11, U2 and Ethernet controller W5500 as reference power. U6 and U11 use ADA4528-1ARMZ precision operational amplifiers, and provide a reference power supply for comparison with the 4-electrode electrochemical gas sensor of U7, and convert the output current of the 4-electrode electrochemical gas sensor into a voltage. U7 uses a 4-electrode electrochemical gas sensor as a dual chemical gas sensor, which can detect two different chemical gases at the same time, for example, H ₂ S and CO. U1 and U10 use AD5270 digital potentiometer to feedback the chemical gas sensor as voltage, and can set the potentiometer count value through SPI communication. AD7798 high-precision amplifier performs analog-to-digital conversion in this circuit, converts the received analog signal into a digital signal, and communicates to the network module W5500 through SPI. W5500 is a network module, which converts the received digital signal into a network signal, and transmits the signal to a computer or server through RJ45.

Crystal oscillator X2, capacitors C11, C12 and resistor R6 form a clock circuit to provide a reference clock for W5500. RESET is the reset button, and W5500 resets after pressing it. Resistors R14, R15 and R16 are sampling resistors, which provide zero reference for W5500.

An embodiment of the present invention provides a networked dual-channel electrochemical gas detection circuit including a dual-channel gas detection module, a high-precision power supply module connected to the dual-channel gas detection module, and a A digital rheostat module, an analog-to-digital conversion module connected to the digital rheostat module and the dual-channel gas detection module, and an Ethernet controller connected to the analog-to-digital conversion module, wherein the Ethernet controller and the upper computer Connected by network cable, optical fiber or wireless, the analog-to-digital conversion module communicates with the Ethernet controller and converts the analog signal collected by the gas sensor in the dual-channel gas detection module into a digital signal output, which solves the problem of Ordinary gas detectors have a single detection variety, slow signal transmission speed, easy to be interfered, many types of input cards, a large number, a large number of cables and bridges need to be laid, and there are problems such as signal attenuation and delay, which has changed the traditional gas detector. Detect and control networking mode.

Apparently, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. In this way, if the modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (10)

1. The networked double-channel electrochemical gas detection circuit is characterized by comprising a double-channel gas detection module, a high-precision power module connected with the double-channel gas detection module, a digital rheostat module connected with the double-channel gas detection module, an analog-to-digital conversion module connected with the digital rheostat module and the double-channel gas detection module, and an Ethernet controller connected with the analog-to-digital conversion module, wherein the Ethernet controller is connected with an upper computer in a network cable, optical fiber or wireless mode, and the analog-to-digital conversion module is in communication connection with the Ethernet controller and converts analog signals acquired by a gas sensor in the double-channel gas detection module into digital signals for output.

2. The networked dual-channel electrochemical gas detection circuit according to claim 1, wherein the dual-channel gas detection module comprises a precision operational amplifier U6, a resistor R2 connected with a positive input end of the precision operational amplifier U6, a dual-chemical gas sensor U7 connected with an output end of the precision operational amplifier U6, a resistor R1, a resistor R3, a capacitor C1 and a capacitor C2, wherein the resistor R1 and the capacitor C1 are connected in parallel and then connected with a negative input end of the precision operational amplifier U6, and the resistor R1 and the resistor R3 are connected in parallel and then connected in series with the capacitor C2.

3. The networked dual-channel electrochemical gas detection circuit of claim 2, wherein the precision operational amplifier U6 is a low noise precision amplifier ADA4528-1ARMZ, and the dual-chemical gas sensor U7 is a COH-A2 dual-channel gas detection sensor.

4. The networked dual-channel electrochemical gas detection circuit according to claim 1, wherein the high-precision power supply module comprises a direct-current stabilized power supply U4 and a direct-current stabilized power supply U5 which are connected with each other, wherein the direct-current stabilized power supply U4 adopts an ADP7102 power supply module, the direct-current stabilized power supply U5 adopts an ADR3412 power supply module, the direct-current stabilized power supply U4 is used for converting a 5V direct-current power supply into a 3.3V direct-current power supply, and the direct-current stabilized power supply U5 is used for converting a 3.3V direct-current power supply into a 1.2V direct-current power supply.

5. The networked dual-channel electrochemical gas detection circuit of claim 1, wherein the digital varistor module comprises a precision amplifier U11, a precision amplifier U12, a digital varistor U1, a digital resistor U10, a P-channel switching fet U3, a P-channel switching fet U9, a resistor R4, a resistor R8, a resistor R9, a capacitor C3, a capacitor C5, a resistor R7, a resistor R10, a resistor R11, a resistor R12, a capacitor C6, a resistor R13, and a capacitor C4.

6. The networked dual-channel electrochemical gas detection circuit of claim 5, wherein the precision amplifier U11 and the precision amplifier U12 each employ a low noise precision amplifier ADA4528-1ARMZ, the digital varistor U1 and the digital resistor U10 each employ an AD5270 digital varistor, and the P-channel switching fet U3 and the P-channel switching fet U9 each employ an MMBFJ270 fet.

7. The networked dual-channel electrochemical gas detection circuit of claim 6, wherein the analog-to-digital conversion module employs an AD7798 analog-to-digital converter U2 and the ethernet controller employs a W5500 ethernet controller.

8. The networked dual-channel electrochemical gas detection circuit according to claim 6, wherein the 1 st pin TXN of the network communication port of the ethernet controller is connected to a resistor R17, the 2 nd pin TXP of the network communication port of the ethernet controller is connected to a resistor R18, the 5 th pin RXP and the 6 th pin RXN of the network communication port of the ethernet controller are respectively connected to 3 and 6 ports of the resistor R19, the resistor R20 and the RJ-45, the other ends of the resistor R19 and the resistor R20 are connected to a capacitor C21 and a power VCC, the other ends of the capacitor C21 are connected to GND, the 10 th pin EXRES1 of the ethernet controller is connected to a resistor R21, the other ends of the resistor R21 are connected to a switch RESET port as a RESET switch, and the other ends of the switch RESET are connected to GND.

9. The networked dual-channel electrochemical gas detection circuit of claim 6, wherein resistors R6, R7 and R16 are pull-up resistors, and resistors R6, R7 and R16 are connected to the 38 th, 39 th, 40 th, 41 th, 42 th, 43 th, 44 th, 45 th pins RSV, PMODE ports of the ethernet controller respectively, and the other ends GND.

10. The networked dual-channel electrochemical gas detection circuit of claim 6, wherein the clock circuit of the ethernet controller is composed of a capacitor C23, a capacitor C22, a resistor R22, and a crystal oscillator X1, the capacitor C23, the capacitor C22, the resistor R22, and the crystal oscillator X1 are connected to the 31 st pin XO and the 30 th pin XL/CLKIN of the ethernet controller and provide clock signals for the ethernet controller.