Flow measurement device and method based on distributed control system query voltage power supply

Abstract

The invention relates to a flow measurement device and method based on distributed control system query voltage power supply. The flow measurement device comprises a measurement module and an in-situ measurement display system. The in-situ measurement and display system is a system which integrates in-situ instrument flow measurement and display and flow comparison output functions; the in-situ measurement display system is respectively connected with the measurement module and a DI channel of the distributed control system; the measurement module measures the flow of the field device to obtain a flow detection signal; and the in-situ measurement display system performs self-power supply according to the query voltage provided by the distributed control system, performs conversion processing on the flow detection signal, then performs in-situ instrument measurement device flow display, and outputs a flow limit value comparison switch signal to a DI channel of the distributed control system. According to the invention, power can be supplied by utilizing the query voltage of a distributed control system, and meanwhile, the functions of measuring and displaying flow by an on-site instrument and comparing and outputting a flow limit value are integrated, so that the arrangement complexity of an on-site flow measurement system is reduced.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power unit instrument control, and more specifically, to a flow measurement device and method powered by query voltage based on a distributed control system. Background Art

[0002] CPR1000 nuclear power units often need to measure the flow rate of pipeline gas / liquid level / steam. The flow rate is an important parameter for determining the state of the system, and it is necessary to have on-site instrument measurement and display of the flow rate, distributed control system display of the flow rate, and flow limit comparison output function (i.e., flow switch). Flow measurement generally uses a differential pressure flowmeter, that is, an orifice plate and a differential pressure transmitter are used to measure the pressure loss before and after the orifice plate, and the flow rate signal is converted according to the pressure loss. The differential pressure transmitter has an on-site flow display function, and this signal is sent to the secondary instrument of the flow switch for limit comparison or sent to the distributed control system for display. Among them, both the differential pressure transmitter and the switch secondary instrument need to use external power supply, or the secondary instrument and the distributed control system provide active channel power supply.

[0003] Conventional flow measurement cannot integrate the functions of on-site instrument measurement and display of the flow rate and flow limit comparison output, that is, the differential pressure flow transmitter and the secondary instrument cannot be integrated. The differential pressure flow transmitter does not have a flow limit comparison function, and the secondary instrument does not have the function of independently measuring the flow rate. Moreover, both need to use external power supply, or use the active channel of the secondary instrument and the distributed control system to supply power to the differential pressure flow transmitter, which increases the complexity of the system layout for on-site flow measurement. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a flow measurement device and method powered by query voltage based on a distributed control system in view of the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is to construct a flow measurement device powered by query voltage based on a distributed control system, including: a measurement module and an on-site measurement and display system connected to the measurement module; the on-site measurement and display system is a system that integrates the functions of on-site instrument measurement and display of the flow rate and flow comparison output;

[0006] The on-site measurement and display system is respectively connected to the measurement module and the DI channel of the distributed control system;

[0007] The measurement module is used to measure the flow rate of on-site equipment to obtain a flow detection signal;

[0008] The in-situ measurement display system is used to self-power according to the query voltage provided by the distributed control system, and after converting and processing the flow detection signal, display the flow by the in-situ instrument measurement device, and output a flow limit comparison switch signal to the DI channel of the distributed control system.

[0009] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the in-situ measurement display system includes: an input / output module, a power supply module, and a control module;

[0010] The input / output module is connected to the DI channel of the distributed control system, the input end of the power supply module is connected to the input / output module, and the output end of the power supply module is connected to the control module;

[0011] The input / output module is used to receive the query voltage output by the distributed control system through its DI channel, and after processing the query voltage, output a voltage signal to the power supply module; the input / output module is also used to generate the flow limit comparison switch signal according to the drive signal output by the control module;

[0012] The power supply module is used to generate power according to the query voltage, and transmit the power supply signal to the control module to supply power to the control module.

[0013] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the in-situ measurement display system further includes: a display module and a conversion module;

[0014] The display module is connected to the output end of the control module, the input end of the conversion module is connected to the measurement module, and the output end of the conversion module is connected to the control module;

[0015] The conversion module is used to convert and process the flow detection signal and then transport it to the control module;

[0016] The control module is used to receive the flow detection signal, output and display the flow detection signal through the display module, generate the drive signal based on the flow detection signal, and send the drive signal to the input / output module.

[0017] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the input / output module includes: a rectification and filtering unit, a boosting unit, a bucking unit, and a boost / buck switching unit;

[0018] The rectifying and filtering unit is connected to the DI channel of the distributed control system. The input end of the boosting unit is connected to the rectifying and filtering unit, the output end of the boosting unit is connected to the step-up / step-down switching unit, the input end of the bucking unit is connected to the rectifying and filtering unit, and the output end of the bucking unit is connected to the step-up / step-down switching unit;

[0019] The rectifying and filtering unit is used to rectify and filter the query voltage output by the distributed control system through its DI channel, and then output it to the boosting unit and the bucking unit;

[0020] The boosting unit and the bucking unit respectively boost and buck the voltage signal output by the rectifying and filtering unit, and then output it to the step-up / step-down switching unit;

[0021] The step-up / step-down switching unit is used to perform a switching function to supply the voltage signal provided by the boosting unit or the voltage signal provided by the bucking unit to the power supply module.

[0022] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the input / output module further includes: a driving unit and a switching unit;

[0023] The input end of the driving unit is connected to the output end of the control module, the output end of the driving unit is connected to the input end of the switching unit, and the output end of the switching unit is connected to the rectifying and filtering unit;

[0024] The driving unit is used to drive the switching unit to open / close according to the driving signal output by the control module, so as to output the flow limit comparison switch signal to the DI channel of the distributed control system through the rectifying and filtering module.

[0025] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the measurement module is a micro-power pressure sensor;

[0026] The micro-power pressure sensor is used to measure and process the on-site equipment to obtain the flow detection signal.

[0027] In the flow measurement device powered by the query voltage of the distributed control system according to the present invention, the conversion module is an analog-to-digital converter;

[0028] The analog-to-digital converter is used to perform analog-to-digital conversion processing on the flow detection signal, so as to convert the analog flow detection signal into a digital flow detection signal, and send the digital flow detection signal to the control module.

[0029] In the flow measurement device powered by query voltage based on the distributed control system according to the present invention, the control module includes: a microprocessor;

[0030] The microprocessor is used to linearly process and calibrate the flow measurement signal, and then output a drive signal and a flow display signal, send the drive signal to the input / output module, and send the flow display signal to the display module for output display.

[0031] In the flow measurement device powered by query voltage based on the distributed control system according to the present invention, the microprocessor is a micro-power consumption single-chip microcomputer.

[0032] The present invention also provides a flow measurement method powered by query voltage based on the distributed control system, including the following steps:

[0033] Provide power supply to the on-site measurement and display system through the query voltage output by the DI channel of the distributed control system;

[0034] After self-powering according to the query voltage, the on-site measurement and display system starts to work;

[0035] Measure the flow of on-site equipment through the measurement module to obtain a flow detection signal;

[0036] The on-site measurement and display system converts and processes the flow detection signal, then displays the flow on the on-site instrument measurement device, and outputs a flow limit comparison switch signal;

[0037] The switch signal is then sent to the DI channel of the distributed control system.

[0038] Implementing the flow measurement device and method powered by query voltage based on the distributed control system according to the present invention has the following beneficial effects: including: a measurement module and an on-site measurement and display system; the on-site measurement and display system is a system integrating the functions of on-site instrument measurement and display of flow and flow comparison output; the on-site measurement and display system is respectively connected to the measurement module and the DI channel of the distributed control system; the measurement module measures the flow of on-site equipment to obtain a flow detection signal; the on-site measurement and display system self-powers according to the query voltage provided by the distributed control system, and after converting and processing the flow detection signal, displays the flow on the on-site instrument measurement device, and outputs a flow limit comparison switch signal to the DI channel of the distributed control system. The present invention can use the query voltage of the distributed control system for power supply, and at the same time integrates the functions of on-site instrument measurement and display of flow and flow limit comparison output, reducing the complexity of the layout of the on-site flow measurement system. Description of the Drawings

[0039] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0040] Figure 1 is a schematic diagram of the conventional flow measurement principle;

[0041] Figure 2 is a schematic diagram of the flow measurement principle provided by the present invention;

[0042] Figure 3 is a schematic diagram of the internal circuit of the flow measurement device powered by querying voltage based on the distributed control system of the present invention;

[0043] Figure 4 is a schematic flow chart of the flow measurement method powered by querying voltage based on the distributed control system provided by the present invention. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] It can be seen from Figure 1 that conventional flow measurement cannot integrate the functions of on-site instrument measurement and display of flow rate, and comparison and output of flow rate limits. Moreover, both the differential pressure flow transmitter and the secondary instrument need to use external power supply. To solve this problem, the present invention provides a flow measurement device powered by querying voltage based on the distributed control system. This flow measurement device can integrate the functions of on-site instrument measurement and display of flow rate, and comparison and output of flow rate limits, as specifically shown in Figure 2 shown.

[0046] It can be known from Figure 2 that the flow measurement device powered by querying voltage based on the distributed control system provided by the present invention can effectively solve the complexity of the on-site measurement flow system layout, integrate the functions of on-site instrument measurement and display of flow rate, comparison and output of flow rate limits, and use the flow measurement device powered by querying voltage of the distributed control system. That is, the present invention integrates the functions of on-site instrument measurement and display of flow rate, and comparison and output of flow rate limits, that is, it has the functions of a differential pressure flow transmitter and a secondary instrument, can display the on-site flow rate, and has a flow rate limit comparison switch signal output. At the same time, the flow rate limit comparison switch signal output (the channel can be disconnected) is sent to the input end (DI channel) of the distributed control system for reception, and the input end (DI channel) of the distributed control system has the function of querying voltage for channel on-off. The voltage function is generally 24V or 48V, that is, when the channel is on, the DI channel is closed and 24V or 48V is input to determine that the signal contact is closed.

[0047] Refer to Figure 3 , Figure 3This is a preferred embodiment of the flow measurement device powered by query voltage based on the distributed control system provided by the present invention.

[0048] Specifically, as Figure 3 shown, the flow measurement device powered by query voltage based on the distributed control system includes: a measurement module 100 and a local measurement display system 200 connected to the measurement module 100. Among them, the local measurement display system 200 is a system that integrates the functions of local instrument measurement and display of flow rate and flow rate comparison output.

[0049] Among them, the local measurement display system 200 is respectively connected to the measurement module 100 and the DI channel of the distributed control system; the measurement module 100 is used to measure the flow rate of on-site equipment to obtain a flow rate detection signal; the local measurement display system 200 is used to self-power according to the query voltage provided by the distributed control system, and to convert and process the flow rate detection signal and then display the flow rate of the local instrument measurement device, and output a flow rate limit comparison switch signal to the DI channel of the distributed control system. Specifically, as Figure 2 and Figure 3 shown, the distributed control system can both boost the query voltage to the local measurement display system 200 through its DI channel to supply power to the local measurement display system 200 through the query voltage, and at the same time, can detect the flow rate limit comparison switch signal output by the local measurement display system 200 through this DI channel to detect the on / off of the channel.

[0050] In the embodiment of the present invention, the local measurement display system 200 includes: an input / output module 21, a power supply module 22, and a control module 23.

[0051] Among them, the input / output module 21 is connected to the DI channel of the distributed control system, the input end of the power supply module 22 is connected to the input / output module 21, and the output end of the power supply module 22 is connected to the control module 23; the input / output module 21 is used to receive the query voltage output by the distributed control system through its DI channel, and after processing the query voltage, output a voltage signal to the power supply module 22; the input / output module 21 is also used to generate a flow rate limit comparison switch signal according to the drive signal output by the control module 23; the power supply module 22 is used to generate a power supply signal according to the voltage signal and transmit the power supply signal to the control module 23 to supply power to the control module 23.

[0052] Further, the in-situ measurement display system 200 further includes: a display module 25 and a conversion module 24; the display module 25 is connected to the output end of the control module 23, the input end of the conversion module 24 is connected to the measurement module 100, and the output end of the conversion module 24 is connected to the control module 23. The conversion module 24 is configured to convert and process the flow detection signal and then deliver it to the control module 23; the control module 23 is configured to receive the flow detection signal, output and display the flow detection signal through the display module 25, generate a driving signal based on the flow detection signal, and send the driving signal to the input / output module 21.

[0053] In an embodiment of the present invention, the input / output module 21 includes: a rectification and filtering unit 211, a boosting unit 212, a bucking unit 213, and a boost / buck switching unit 214.

[0054] The rectification and filtering unit 211 is connected to the DI channel of the distributed control system. The input end of the boosting unit 212 is connected to the rectification and filtering unit 211, the output end of the boosting unit 212 is connected to the boost / buck switching unit 214, the input end of the bucking unit 213 is connected to the rectification and filtering unit 211, and the output end of the bucking unit 213 is connected to the boost / buck switching unit 214.

[0055] The rectification and filtering unit 211 is configured to rectify and filter the query voltage output by the distributed control system through its DI channel and then output it to the boosting unit 212 and the bucking unit 213. The boosting unit 212 and the bucking unit 213 respectively boost and buck the voltage signal output by the rectification and filtering unit 211 and then output it to the boost / buck switching unit 214. The boost / buck switching unit 214 is configured to perform a switching function to provide the voltage signal provided by the boosting unit 212 or the voltage signal provided by the bucking unit 213 to the power supply module 22.

[0056] Further, the input / output module 21 further includes: a driving unit 215 and a switching unit 216.

[0057] The input end of the driving unit 215 is connected to the output end of the control module 23, the output end of the driving unit 215 is connected to the input end of the switching unit 216, and the output end of the switching unit 216 is connected to the rectification and filtering unit 211. The driving unit 215 is configured to drive the switching unit 216 to open / close according to the driving signal output by the control module 23, so as to output a flow limit comparison switch signal to the DI channel of the distributed control system through the rectification and filtering module. Optionally, the switching unit 216 may be an IGBT switch.

[0058] Optionally, in an embodiment of the present invention, the measurement module 100 is a micro-power consumption pressure sensor; the micro-power consumption pressure sensor is configured to measure and process the field device to obtain a flow detection signal.

[0059] Optionally, in the embodiments of the present invention, the conversion module 24 is an analog-to-digital converter; the analog-to-digital converter is used to perform analog-to-digital conversion processing on the flow detection signal to convert the analog flow detection signal into a digital flow detection signal, and send the digital flow detection signal to the control module 23.

[0060] Optionally, in the embodiments of the present invention, the control module 23 includes: a microprocessor; the microprocessor is used to perform linear and calibration processing on the flow measurement signal, and then output a drive signal and a flow display signal, send the drive signal to the input / output module 21, and send the flow display signal to the display module 25 for output display. Preferably, the microprocessor is a micro-power consumption single-chip microcomputer.

[0061] In the embodiments of the present invention, the query voltage of the distributed control system is an open-circuit voltage, and a channel failure will be triggered when the query voltage is too low. When using the query voltage to supply power to the instrument, first, the query voltage cannot flow back to the distributed control system due to the instrument's ground terminal and mis-trigger the channel to close, and second, the voltage drop requirement of the query voltage cannot be too low, that is, the power consumption requirement of the instrument is low. Therefore, the measurement module 100 of the present invention uses a micro-power consumption pressure sensor (generally 0.16 mA). At the same time, the microprocessor used is also a micro-power consumption single-chip microcomputer. The micro-power consumption single-chip microcomputer processes the flow detection signal output by the micro-power consumption pressure sensor (such as linearization, calibration, etc.), outputs a DO (i.e., drive signal) to control the drive unit 215 to control the on / off state of the switch unit 216, and sends it to the distributed control system, that is, it is detected through the DI channel of the distributed control system.

[0062] Among them, the distributed control system referred to in the present invention can be a DCS system (distributed control system) or a PLC system of a nuclear power plant.

[0063] Specifically, as Figure 3 shown, the distributed control system outputs a query voltage through its DI channel, the query voltage is input to the input / output module 21, and after rectification, filtering, step-up and step-down processing by the input / output module 21, it is output to the power supply module 22, and the power supply module 22 supplies power to the micro-power consumption single-chip microcomputer, and the micro-power consumption single-chip microcomputer works normally. The flow detection signal measured by the micro-power consumption pressure sensor is subjected to analog-to-digital conversion processing by the analog-to-digital conversion module 24, and the digital flow detection signal is transmitted to the micro-power consumption single-chip microcomputer. After the micro-power consumption single-chip microcomputer processes the digital flow detection signal, a DO signal (i.e., drive signal) is generated, and the IGBT switch is driven through this DO signal. That is, when the flow detection signal is greater than or lower than the set threshold, the switch closes, and the DI channel signal queries that the switch is closed, and it is determined that the channel is connected. Otherwise, the switch opens, and the DI channel signal queries that the switch is open.

[0064] Specifically, in a distributed control system, the DI channel generally detects the status of local switches. That is, when the switch is closed, the DI channel inputs a high level; when the switch is open, the DI channel inputs a low level (no voltage). The DI channel has a function to query voltage, generally 24 / 48V, which is an open-circuit voltage. Combining the above, when the switch is closed, the voltage detected by the DI channel is 24 / 48V, which is a high level, and when it is open, no voltage is detected.

[0065] The flow measurement device of the present invention based on querying voltage power supply of a distributed control system integrates functions such as local instrument measurement and display of flow rate, and comparison and output of flow rate limit values, and uses the DI channel of the distributed control system to query voltage for self-power supply, reducing the complexity of the layout of the on-site flow measurement system. Compared with the conventional on-site flow measurement system, fewer devices need to be arranged, resulting in lower costs and less on-site installation space requirements.

[0066] Reference Figure 4 , Figure 4 A flow measurement method based on querying voltage power supply of a distributed control system provided by the present invention is provided. The flow measurement method based on querying voltage power supply of a distributed control system can be applied to the flow measurement device based on querying voltage power supply of a distributed control system disclosed in the embodiments of the present invention.

[0067] Specifically, as Figure 4 shown, the flow measurement method based on querying voltage power supply of a distributed control system includes the following steps:

[0068] Step S401: Provide power supply to the local measurement and display system 200 through the query voltage output by the DI channel of the distributed control system.

[0069] Step S402: After self-powering according to the query voltage, the local measurement and display system 200 starts to work.

[0070] Step S403: Measure the flow rate of on-site equipment through the measurement module 100 to obtain a flow rate detection signal.

[0071] Step S404: After converting and processing the flow rate detection signal, the local measurement and display system 200 measures and displays the flow rate by the local instrument measurement device and outputs a flow rate limit comparison switch signal.

[0072] Step S405: The switch signal is then sent to the DI channel of the distributed control system. That is, the distributed control system detects the flow rate limit comparison switch signal through its DI channel.

[0073] In the present specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0074] Those skilled in the art can further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0075] The steps of the methods or algorithms described in combination with the embodiments disclosed herein can be directly implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0076] The above embodiments are only used to illustrate the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They do not limit the protection scope of the present invention. All equivalent changes and modifications made to the scope of the claims of the present invention shall fall within the scope covered by the claims of the present invention.

Claims

1. A flow measurement device based on a distributed control system query voltage power supply, characterized in that: include: A measuring module and an on-site measuring display system connected to the measuring module; The local measurement and display system is a system that integrates the local instrument flow measurement and display and flow comparison output functions; The local measurement display system is connected to the measurement module and the DI channel of the distributed control system respectively; The measuring module is used to measure the flow rate of the field equipment and obtain a flow rate detection signal; The local measurement and display system is used to self-power according to the query voltage provided by the distributed control system, and to display the flow rate on the local instrument measurement device after converting and processing the flow detection signal, and output the flow limit comparison switch signal to the DI channel of the distributed control system.

2. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 1 is characterized in that: The on-site measurement and display system comprises: an input / output module, a power supply module and a control module; The input / output module is connected to the DI channel of the distributed control system, the input end of the power supply module is connected to the input / output module, and the output end of the power supply module is connected to the control module; The input / output module is used to receive the query voltage output by the distributed control system through its DI channel, and output a voltage signal to the power supply module after processing the query voltage; the input / output module is also used to generate the flow limit comparison switch signal according to the drive signal output by the control module; The power supply module is used to generate a power supply signal according to the voltage signal, and transmit the power supply signal to the control module to supply power to the control module.

3. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 2 is characterized in that: The on-site measurement display system also includes: a display module and a conversion module; The display module is connected to the output end of the control module, the input end of the conversion module is connected to the measurement module, and the output end of the conversion module is connected to the control module; The conversion module is used to convert the flow detection signal and transmit it to the control module; The control module is used to receive the flow detection signal, output and display the flow detection signal through the display module, generate the drive signal based on the flow detection signal, and send the drive signal to the input / output module.

4. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 2 is characterized in that: The input / output module includes: a rectifying and filtering unit, a boost unit, a buck unit and a boost / buck switching unit; The rectifier and filter unit is connected to the DI channel of the distributed control system, the input end of the boost unit is connected to the rectifier and filter unit, the output end of the boost unit is connected to the boost / buck switching unit, the input end of the buck unit is connected to the rectifier and filter unit, and the output end of the buck unit is connected to the boost / buck switching unit; The rectifying and filtering unit is used to rectify and filter the query voltage output by the distributed control system through its DI channel, and then output it to the boost unit and the buck unit; The voltage boost unit and the voltage buck unit respectively perform voltage boost processing and voltage buck processing on the voltage signal output by the rectifier and filter unit, and then output the result to the voltage boost / buck switching unit; The voltage step-up / step-down switching unit is used to perform a switching function to provide the voltage signal provided by the voltage step-up unit or the voltage signal provided by the voltage step-down unit to the power supply module.

5. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 4 is characterized in that: The input / output module further includes: a driving unit and a switch unit; The input end of the driving unit is connected to the output end of the control module, the output end of the driving unit is connected to the input end of the switch unit, and the output end of the switch unit is connected to the rectifier and filter unit; The driving unit is used to drive the switch unit to open / disconnect according to the driving signal output by the control module, so as to output the flow limit comparison switch signal to the DI channel of the distributed control system through the rectification and filtering module.

6. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 1 is characterized in that: The measuring module is a micro-power consumption pressure sensor; The micro-power consumption pressure sensor is used to measure and process the field equipment to obtain the flow detection signal.

7. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 3 is characterized in that: The conversion module is an analog / digital converter; The analog / digital converter is used to perform analog-to-digital conversion processing on the flow detection signal to convert the analog flow detection signal into a digital flow detection signal, and send the digital flow detection signal to the control module.

8. The flow measurement device based on the query voltage power supply of the distributed control system according to any one of claims 1 to 7, characterized in that: The control module includes: a microprocessor; The microprocessor is used to output a drive signal and a flow display signal after performing linear and calibration processing on the flow measurement signal, and send the drive signal to the input / output module, and send the flow display signal to the display module for output display.

9. The flow measurement device based on the query voltage power supply of the distributed control system according to claim 8 is characterized in that: The microprocessor is a micro-power single-chip microcomputer.

10. A flow measurement method based on querying voltage power supply of a distributed control system, characterized in that: The following steps are involved: The query voltage output by the DI channel of the distributed control system provides power to the local measurement and display system; The on-site measurement and display system starts working after being self-powered according to the query voltage; The flow rate of the field equipment is measured by the measurement module to obtain a flow detection signal; The local measurement and display system converts and processes the flow detection signal, displays the flow on the local instrument measurement device, and outputs a flow limit comparison switch signal; The switch signal is then sent to the DI channel of the distributed control system.

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