CN216848575U - High-precision electronic pressure flow closed-loop control system for gas - Google Patents
High-precision electronic pressure flow closed-loop control system for gas Download PDFInfo
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Abstract
The utility model relates to a high-precision electronic pressure flow closed-loop control system for gas, which comprises a flow proportional valve, a flow sensor, an ADC (analog-to-digital converter) chip, an MCU (micro control unit), a DAC (digital-to-analog converter) chip and an adjustable current source module, wherein the flow sensor is electrically connected with the input end of the ADC chip, the MCU is respectively and electrically connected with the ADC chip and the DAC chip, and the output end of the DAC chip is electrically connected with the input end of the adjustable current source module; the flow proportional valve is provided with an electric signal input end and an electric signal feedback end, the execution end of the adjustable current source module is electrically connected with the electric signal input end of the flow proportional valve, and the electric signal feedback end of the flow proportional valve is electrically connected with the feedback end of the adjustable current source module. The high-precision electronic pressure flow closed-loop control system for the gas forms a closed-loop system for controlling the gas flow by using the adjustable current source module, and improves the control precision of the gas flow.
Description
Technical Field
The utility model relates to the technical field of gas flow pressure control, in particular to a high-precision electronic pressure flow closed-loop control system for gas.
Background
An electronic Pressure flow control (EPC) is a key component of a Gas Chromatograph (GC) Gas path system, and is used for accurately controlling the front Pressure and flow rate of a Gas-carrying column, and the performance of the EPC directly determines key indexes of the Gas chromatograph, such as detection sensitivity, retention time, peak area repeatability and the like.
The traditional electronic pressure flow controller has low control precision and is difficult to meet the control requirement of high precision.
SUMMERY OF THE UTILITY MODEL
In view of the above, it is necessary to provide a high-precision electronic pressure-flow closed-loop control system for controlling a gas with high precision.
A high-precision electronic pressure flow closed-loop control system for gas comprises a flow proportional valve, a flow sensor, an ADC chip, an MCU, a DAC chip and an adjustable current source module, wherein the flow sensor is electrically connected with the input end of the ADC chip, the MCU is electrically connected with the ADC chip and the DAC chip respectively, and the output end of the DAC chip is electrically connected with the input end of the adjustable current source module; the flow proportional valve is provided with an electric signal input end and an electric signal feedback end, the execution end of the adjustable current source module is electrically connected with the electric signal input end of the flow proportional valve, and the electric signal feedback end of the flow proportional valve is electrically connected with the feedback end of the adjustable current source module;
The flow sensor obtains the gas output flow of flow proportional valve and generates the air current analog signal, the ADC chip will the air current analog signal converts the air current digital signal into and handles and input MCU, MCU is right the air current digital signal is handled and output voltage digital signal, DAC will the voltage digital signal converts voltage analog signal into voltage analog signal and input adjustable current source module's input, adjustable current source module basis the electric signal feedback end output feedback voltage of flow proportional valve with the voltage analog signal that DAC output, output current control signal and input the electric signal input part of flow proportional valve adjusts the gas output flow of flow proportional valve.
Furthermore, the adjustable current source module comprises an operational amplifier chip set and a current driving chip, wherein the current driving chip is electrically connected with an execution end of the operational amplifier chip set.
Furthermore, the device also comprises a first sampling resistor, wherein one end of the first sampling resistor is connected with one end of the coil of the flow proportional valve, and the other end of the first sampling resistor is grounded; the feedback voltage is the voltage of a joint end of the first sampling resistor and the coil of the flow proportional valve, and the electric signal input end of the flow proportional valve is the other end of the coil of the flow proportional valve.
The device further comprises a pressure proportional valve, a pressure sensor and another adjustable current source module, wherein the pressure proportional valve is connected to the downstream of the flow proportional valve, the pressure sensor is electrically connected with another input end of the ADC chip, and another output end of the DAC chip is electrically connected with an input end of the another adjustable current source module; the output end of the other adjustable current source module is electrically connected with the signal input end of the pressure proportional valve, and the feedback end of the pressure proportional valve is electrically connected with the other input end of the other adjustable current source module; the pressure sensor detects the air pressure between the pressure proportional valve and the flow proportional valve.
Further, the another adjustable current source module includes another operational amplifier chipset and another current driver chip, and the another current driver chip is electrically connected to the execution end of the another operational amplifier chipset.
Furthermore, the pressure proportional valve further comprises a second sampling resistor, one end of the second sampling resistor is connected with one end of the coil of the pressure proportional valve, and the other end of the second sampling resistor is grounded; the feedback voltage is the voltage of a joint end of the first sampling resistor and the coil of the pressure proportional valve, and the electric signal input end of the flow proportional valve is the other end of the coil of the pressure proportional valve.
Furthermore, the ADC chip is a 24-bit chip, and the DAC chip is a 16-bit chip.
Further, a pressure stabilizing valve is connected to the upstream of the flow proportional valve.
According to the high-precision electronic pressure flow closed-loop control system for the gas, the flow analog signal is transmitted into the MCU through the ADC chip, the voltage digital signal is transmitted to the DAC chip after data processing, the DAC generates a corresponding voltage analog signal and inputs the voltage analog signal into the control end of the adjustable current source module, the current of the execution end of the adjustable current source module drives the flow proportional valve, and the flow proportional valve outputs feedback voltage to the feedback end of the adjustable current source module, so that a closed-loop system for controlling the gas flow by using the adjustable current source module is formed, and the control precision of the gas flow is improved.
Drawings
FIG. 1 is a schematic diagram of a high-precision electronic pressure-flow closed-loop control system for gas according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, in one embodiment, a high-precision electronic pressure-flow closed-loop control system for gas includes a flow proportional valve 110, a flow sensor 120, an Analog-to-Digital Converter (ADC) chip 130, a Micro Controller Unit (MCU), a Digital-to-Analog Converter (DAC) chip 140, and an adjustable current source module 150. The flow sensor 120 is electrically connected to an input end of the ADC chip 130, the MCU is electrically connected to the ADC chip 130 and the DAC chip 140, and an output end of the DAC chip 140 is electrically connected to an input end of the adjustable current source module 150. The flow proportional valve 110 has an electrical signal input end and an electrical signal feedback end, the execution end of the adjustable current source module 150 is electrically connected to the electrical signal input end of the flow proportional valve 110, and the electrical signal feedback end of the flow proportional valve 110 is electrically connected to the feedback end of the adjustable current source module 150. A pressure maintaining valve 190 is connected upstream of the flow rate proportional valve 110. Specifically, the adjustable current source module 150 includes an operational amplifier chipset and a current driver chip, and the current driver chip is electrically connected to an execution end of the operational amplifier chipset. The ADC chip 130 and the DAC chip 140 are high-precision chips. The ADC chip is a 24-bit chip, and the DAC chip is a 16-bit chip. The flow sensor 120 is a mass flow sensor.
The flow sensor 120 obtains the gas output flow of the flow proportional valve 110 and generates a gas flow analog signal, the ADC chip 130 converts the gas flow analog signal into a gas flow digital signal for processing and inputting into the MCU, and the MCU processes the gas flow digital signal and outputs a voltage digital signal. The DAC converts the voltage digital signal into a voltage analog signal and inputs the voltage analog signal to an input terminal of the adjustable current source module 150. The adjustable current source module 150 outputs a feedback voltage and a voltage analog signal output by the DAC according to the electric signal feedback end of the flow proportional valve 110, outputs a current control signal and inputs the current control signal to the electric signal input end of the flow proportional valve 110, and adjusts the gas output flow of the flow proportional valve 110.
The high-precision electronic pressure flow closed-loop control system for the gas transmits a flow analog signal into the MCU through the ADC chip 130, and after data processing, a voltage digital signal is sent to the DAC chip 140, the DAC generates a corresponding voltage analog signal and inputs the voltage analog signal into the control end of the adjustable current source module 150, the current at the execution end of the adjustable current source module 150 drives the flow proportional valve 110, and the flow proportional valve 110 outputs a feedback voltage to the feedback end of the adjustable current source module 150, so that a closed-loop system for controlling the gas flow by using the adjustable current source module 150 is formed, and the control precision of the gas flow is improved.
In this embodiment, the high-precision electronic pressure-flow closed-loop control system for gas further includes a first sampling resistor R1, one end of the first sampling resistor R1 is connected to one end of the coil of the flow proportional valve 110, and the other end is grounded. The feedback voltage is a voltage of a connection end of the first sampling resistor R1 and the coil of the flow proportional valve 110, and the electrical signal input end of the flow proportional valve 110 is the other end of the coil of the flow proportional valve 110. The first sampling resistor R1 is a low-resistance high-precision low-temperature drift resistor.
In this embodiment, the high-precision electronic pressure-flow closed-loop control system for gas further includes a pressure proportional valve 160, a pressure sensor 170, another adjustable current source module 180, and a second sampling resistor R2, wherein the pressure proportional valve 160 is connected downstream of the flow proportional valve 110, the pressure sensor 170 is electrically connected to another input terminal of the ADC chip 130, and another output terminal of the DAC chip 140 is electrically connected to an input terminal of another adjustable current source module 180. The output end of the other adjustable current source module 180 is electrically connected to the signal input end of the pressure proportional valve 160, and the feedback end of the pressure proportional valve 160 is electrically connected to the other input end of the other adjustable current source module 180. The pressure sensor 170 senses the air pressure between the pressure proportional valve 160 and the flow proportional valve 110. The other adjustable current source module 180 includes another operational amplifier chipset and another current driving chip electrically connected to the execution end of the other operational amplifier chipset. One end of the second sampling resistor R2 is connected to one end of the coil of the pressure proportional valve 160, and the other end is grounded. The feedback voltage is the voltage of the connection end of the second sampling resistor R2 and the coil of the pressure proportional valve 160, and the electrical signal input end of the flow proportional valve 110 is the other end of the coil of the pressure proportional valve 160. The second sampling resistor R2 adopts a low-resistance high-precision low-temperature drift resistor. The flow proportional valve 110 and the pressure proportional valve 170 are small-bore proportional valves. The gas flow path is formed by metal pipes, the flow proportional valve 110 fastened by a mechanical block, the flow sensor 120, the pressure sensor 170 and the pressure proportional valve 160, and is connected to the circuit board through a lead.
The pressure analog signal is transmitted to the MCU through the ADC chip 130, and the data processing is performed to transmit the pressure digital signal of the air pressure to the DAC chip 140, the DAC generates a corresponding pressure analog signal of the air pressure and inputs the pressure analog signal to the control end of the other adjustable current source module 180, the other adjustable current source module 180 executes an end current driving voltage proportional valve, and the voltage proportional valve outputs a feedback voltage to the feedback end of the other adjustable current source module 180, so that a closed-loop system for controlling the air pressure by the other adjustable current source module 180 is formed, and the control precision of the air pressure is improved.
The working process comprises the following steps: the airflow flows through the flow sensor 120, the flow sensor 120 outputs an electric signal with a certain voltage value, the electric signal is collected by the ADC chip 130 and then transmitted to the MCU, the MCU compares a set value with an actual value, calculates an adjustment value through a prestored algorithm and transmits the adjustment value to the DAC chip 140, and the DAC value adjusts the current of the current source to drive the flow proportional valve 110 for controlling the flow. The airflow continues to advance, passes through the chromatographic column 50, a part of the airflow enters the chromatographic column, the rest of the airflow reaches the pressure sensor 170, the pressure sensor 170 outputs a certain voltage value, the voltage value is collected by the ADC and enters the MCU, the MCU calculates a corresponding control value through an operation algorithm according to a set value, the control value is transmitted to the DAC, and the DAC value adjusts the current of the current source to drive the pressure proportional valve 160 for controlling the pressure. The control precision of the gas flow and the pressure can be greatly improved through the double closed loops. The utility model adopts a closed-loop control circuit formed by combining high-precision AD and DA chips with a current source to greatly improve the stepping precision of the proportional valve control, the pressure control precision reaches 0.001psi, the flow control precision reaches 0.01ml/min, and the gas flow, the pressure control precision and the range are greatly improved.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the present invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the utility model, and these changes and modifications are all within the scope of the utility model. Therefore, the protection scope of the present patent should be subject to the appended claims.
Claims (8)
1. The high-precision electronic pressure flow closed-loop control system for the gas is characterized by comprising a flow proportional valve, a flow sensor, an ADC (analog to digital converter) chip, an MCU (micro control unit), a DAC (digital to analog converter) chip and an adjustable current source module, wherein the flow sensor is electrically connected with the input end of the ADC chip, the MCU is electrically connected with the ADC chip and the DAC chip respectively, and the output end of the DAC chip is electrically connected with the input end of the adjustable current source module; the flow proportional valve is provided with an electric signal input end and an electric signal feedback end, the execution end of the adjustable current source module is electrically connected with the electric signal input end of the flow proportional valve, and the electric signal feedback end of the flow proportional valve is electrically connected with the feedback end of the adjustable current source module;
The flow sensor obtains the gas output flow of the flow proportional valve and generates a gas flow analog signal, the ADC chip converts the gas flow analog signal into a gas flow digital signal to be processed and input into the MCU, the MCU processes the gas flow digital signal and outputs a voltage digital signal, the DAC converts the voltage digital signal into a voltage analog signal and inputs the voltage analog signal into the input end of the adjustable current source module, and the adjustable current source module outputs a feedback voltage and the voltage analog signal output by the DAC according to the electric signal feedback end of the flow proportional valve, outputs a current control signal and inputs the electric signal input end of the flow proportional valve to adjust the gas output flow of the flow proportional valve.
2. The closed-loop control system for high-precision electronic pressure and flow of gas as claimed in claim 1, wherein the adjustable current source module comprises an operational amplifier chip set and a current driving chip, and the current driving chip is electrically connected with an execution end of the operational amplifier chip set.
3. The system of claim 1, further comprising a first sampling resistor, wherein one end of the first sampling resistor is connected to one end of the coil of the flow proportional valve, and the other end of the first sampling resistor is grounded; the feedback voltage is the voltage of a joint end of the first sampling resistor and the coil of the flow proportional valve, and the electric signal input end of the flow proportional valve is the other end of the coil of the flow proportional valve.
4. The system of claim 3, further comprising a pressure proportional valve, a pressure sensor and another adjustable current source module, wherein the pressure proportional valve is connected downstream of the flow proportional valve, the pressure sensor is electrically connected to another input terminal of the ADC chip, and another output terminal of the DAC chip is electrically connected to an input terminal of the another adjustable current source module; the output end of the other adjustable current source module is electrically connected with the signal input end of the pressure proportional valve, and the feedback end of the pressure proportional valve is electrically connected with the other input end of the other adjustable current source module; the pressure sensor detects the air pressure between the pressure proportional valve and the flow proportional valve.
5. The closed-loop control system for high-precision electronic pressure and flow of gas as claimed in claim 4, wherein the another adjustable current source module comprises another operational amplifier chip set and another current driving chip, and the another current driving chip is electrically connected with an execution end of the another operational amplifier chip set.
6. The closed-loop control system for high-precision electronic pressure flow of gas as claimed in claim 4, further comprising a second sampling resistor, one end of the second sampling resistor is connected to one end of the coil of the pressure proportional valve, and the other end is grounded; the feedback voltage is the voltage of a joint end of the first sampling resistor and the coil of the pressure proportional valve, and the electric signal input end of the flow proportional valve is the other end of the coil of the pressure proportional valve.
7. The system of claim 1, wherein the ADC chip is a 24-bit chip and the DAC chip is a 16-bit chip.
8. A high accuracy electronic pressure flow closed loop control system of gases as claimed in any one of claims 1 to 7 wherein a pressure maintaining valve is connected upstream of said flow proportional valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122946735.1U CN216848575U (en) | 2021-11-26 | 2021-11-26 | High-precision electronic pressure flow closed-loop control system for gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122946735.1U CN216848575U (en) | 2021-11-26 | 2021-11-26 | High-precision electronic pressure flow closed-loop control system for gas |
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| Publication Number | Publication Date |
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| CN216848575U true CN216848575U (en) | 2022-06-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122946735.1U Active CN216848575U (en) | 2021-11-26 | 2021-11-26 | High-precision electronic pressure flow closed-loop control system for gas |
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| CN (1) | CN216848575U (en) |
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- 2021-11-26 CN CN202122946735.1U patent/CN216848575U/en active Active
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