A multi-channel sensing device suitable for use in a transmitter and flow computer

Abstract

The application relates to the field of device detection correction, in particular to a multi-channel detection device suitable for transmitters and flow computers. The application sets a change-over switch and multiple detection channels, so that multiple devices can be detected at one time, thereby improving the detection efficiency and reducing the use frequency of standard devices and pressure pumps; and through the combination of a current / voltage conversion circuit and a thermal resistance value conversion circuit, a pressure transmitter or a temperature transmitter with standard current output can be integrated into one device for detection, thereby effectively increasing the universality of the application.

Description

Technical Field

[0001] This invention relates to the field of equipment testing and calibration, and in particular to a multi-channel testing device suitable for transmitters and flow computers. Background Technology

[0002] With the continuous development of information-based gas field construction, a large number of current-output pressure transmitters and temperature transmitters need to be periodically calibrated. However, in the metrology and testing process, traditional testing methods can only calibrate one pressure transmitter, calibrate one temperature transmitter, or calibrate one signal channel of a flow computer at a time.

[0003] Traditional testing methods, existing standard equipment configurations, and the number of testing personnel are insufficient to meet the needs of testing a large number of measuring instruments, resulting in a large number of pressure transmitters and temperature transmitters operating beyond their service life. Therefore, there is a need for a method that can reduce repeated pressurization (one pressurization can test multiple current-output pressure transmitters with the same range) and repeated rotation of DC resistor values ​​(one rotation of DC resistor values ​​can test multiple current-output temperature transmitters or flow totalizers with the same range), and achieve the ability to simultaneously test multiple pressure transmitters, temperature transmitters, and flow computer signal channels, in order to avoid pressure transmitters and temperature transmitters operating beyond their service life due to untimely testing. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems in the prior art that only one device can be detected at a time and that the detection devices cannot be integrated, and to provide a multi-channel detection device suitable for transmitters and flow computers.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A multi-channel detection device suitable for transmitters and flow computers includes detection modules and AC / DC conversion circuits that are electrically connected to each other. The detection modules include a changeover switch and a plurality of detection units that are electrically connected to the changeover switch.

[0007] The detection unit includes a current / voltage conversion circuit, a thermal resistance conversion circuit, a first connector, and a second connector.

[0008] The current / voltage conversion circuit and the thermal resistance conversion circuit are electrically connected to each other; the first connector is electrically connected to the current / voltage conversion circuit and is used to connect an external current source; the second connector is electrically connected to the thermal resistance conversion circuit and is used to connect an external DC resistor.

[0009] The changeover switch is used to switch the connected detection unit. This invention, by setting up a changeover switch and multiple detection channels, enables the simultaneous detection of multiple devices, thereby improving detection efficiency and reducing the frequency of use of standards and pressure pumps. Furthermore, by combining a current / voltage conversion circuit and a thermal resistance conversion circuit, it integrates the detection of pressure transmitters or temperature transmitters that output standard current into a single device, effectively increasing the versatility of this invention.

[0010] As a preferred embodiment of the present invention, the first connector includes three connection ports, and the current / voltage conversion circuit includes a relay switch and positive and negative detection ports for connecting the transmitter under test;

[0011] Port 1 of the first connector is electrically connected to the changeover switch;

[0012] The drive coil of the relay switch is electrically connected to the changeover switch. The two ends of the contacts of the relay switch are electrically connected to port 2 and the positive detection port of the first connector, respectively, and the negative detection port is electrically connected to port 3 of the first connector.

[0013] As a preferred embodiment of the present invention, a protection circuit is provided between the AC / DC conversion circuit and port 1 of the first connector.

[0014] As a preferred embodiment of the present invention, the protection circuit includes a current-limiting resistor and a reverse diode connected in sequence.

[0015] As a preferred embodiment of the present invention, the first connector further includes a spare port. The spare port is used as an emergency replacement in case ports 1-3 fail.

[0016] As a preferred embodiment of the present invention, the relay switch is an opto-isolated relay.

[0017] As a preferred embodiment of the present invention, the second connector includes n connection ports, and the thermal resistance conversion circuit includes n relay switches and a resistor port for connecting the thermal resistor, where n is an integer greater than 1.

[0018] The drive coil of the i-th relay switch is electrically connected to the current / voltage conversion circuit corresponding to the detection unit, and the two ends of the contacts of the relay switch are electrically connected to the i-th port and the resistor port of the second connector, respectively, i∈[1,n].

[0019] As a preferred embodiment of the present invention, the relay switch is an opto-isolated relay.

[0020] As a preferred embodiment of the present invention, the line resistance deviation between any two of the detection units is less than 5mΩ. Through precise line configuration, the present invention achieves a thermal resistance conversion accuracy of ≤±0.05℃ and a current / voltage conversion accuracy of ≤±0.01%FS, effectively improving the detection accuracy and reducing measurement errors.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. This invention enables the simultaneous testing of multiple devices by setting up a conversion switch and multiple detection channels, thereby improving testing efficiency and reducing the frequency of use of standards and pressure pumps; and by combining current / voltage conversion circuit and thermal resistance conversion circuit, it integrates the testing of pressure transmitters or temperature transmitters with standard current output into one device, thereby effectively increasing the universality of this invention.

[0023] 2. By precisely setting the circuit, this invention achieves a thermal resistance conversion accuracy of ≤ ±0.05℃ and a current / voltage conversion accuracy of ≤ ±0.01%FS, effectively improving the detection accuracy of this invention and reducing measurement errors. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a multi-channel detection device suitable for transmitters and flow computers according to Embodiment 1 of the present invention;

[0025] Figure 2 This is an electrical schematic diagram of a multi-channel detection device suitable for transmitters and flow computers according to Embodiment 3 of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a multi-channel detection device suitable for transmitters and flow computers according to Embodiment 3 of the present invention;

[0027] Figure 4 This is the channel wiring diagram for detecting the pressure signal of the QJG02-X flow computer using a ConsT811 constant current source in a multi-channel detection device suitable for transmitters and flow computers, as described in Embodiment 3 of the present invention.

[0028] Figure 5 This is the channel wiring diagram for detecting the temperature signal of the QJG02-X flow computer using a ConsT811 constant current source in a multi-channel detection device suitable for transmitters and flow computers, as described in Embodiment 3 of the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0030] Example 1

[0031] like Figure 1 As shown, a multi-channel detection device suitable for transmitters and flow computers includes detection modules and AC / DC conversion circuits that are electrically connected to each other. The detection module includes a changeover switch and several detection units that are electrically connected to the changeover switch.

[0032] The detection unit includes a current / voltage conversion circuit, a thermal resistance conversion circuit, a first connector, and a second connector.

[0033] The current / voltage conversion circuit and the thermal resistance conversion circuit are electrically connected to each other; the first connector is electrically connected to the current / voltage conversion circuit and is used to connect an external current source; the second connector is electrically connected to the thermal resistance conversion circuit and is used to connect an external DC resistor.

[0034] The switch is used to switch the detection unit connected to it.

[0035] The first connector includes three connection ports, and the current / voltage conversion circuit includes a relay switch and positive and negative detection ports for connecting the transmitter under test.

[0036] Port 1 of the first connector is electrically connected to the changeover switch;

[0037] The drive coil of the relay switch is electrically connected to the changeover switch. The two ends of the contacts of the relay switch are electrically connected to port 2 and the positive detection port of the first connector, respectively, and the negative detection port is electrically connected to port 3 of the first connector.

[0038] The second connector includes n connection ports, and the thermal resistance conversion circuit includes n relay switches and a resistor port for connecting the thermal resistance, where n is an integer greater than 1.

[0039] The drive coil of the i-th relay switch is electrically connected to the current / voltage conversion circuit corresponding to the detection unit, and the two ends of the contacts of the relay switch are electrically connected to the i-th port and the resistor port of the second connector, respectively, i∈[1,n].

[0040] The relay switches in the current / voltage conversion circuit and the thermal resistance conversion circuit are opto-isolated relays, and the line resistance deviation between any two detection units is less than 5mΩ.

[0041] Example 2

[0042] The difference between this embodiment and Embodiment 1 is that a protection circuit is provided between the AC / DC conversion circuit and port 1 of the first connector; the first connector also includes a spare port.

[0043] The protection circuit includes a current-limiting resistor and a reverse diode connected in sequence. The spare port is used as an emergency replacement in case of a failure of ports 1-3.

[0044] Example 3

[0045] like Figure 2 and Figure 3 As shown, this embodiment is a practical application example of the device described in Embodiment 2 when the detection unit is 8 and n is 4. In this case, the selector switch is an 8-position rotary switch K1. The following are examples of actual detection applications:

[0046] 1. Connecting a handheld communicator to set or calibrate the transmitter (current-type pressure transmitter or temperature transmitter):

[0047] Connect the 250Ω load resistor to the signal input terminals (i.e., the first connector) 1 and 2 of the current / voltage conversion circuit 4, and then connect the signal lines of the handheld communicator to both sides of the load resistor. Through the changeover switch 2, the handheld communicator can be connected to each transmitter. The status of the transmitter can be set and verified using the handheld communicator.

[0048] 2. Pressure transmitter testing:

[0049] (1) Connect a precision ammeter to input terminals 1 and 2 of the current / voltage converter circuit 4 (signal input terminals 3 and 4 of the current / voltage converter circuit 4 are not used). At this time, the thermal resistance conversion circuit 3 does not work. The signal output of the current / voltage conversion circuit 4 is controlled by the changeover switch 2 (each time the switch is changed, only the same signal output terminal with the same switch position provides power to the pressure transmitter). At the same time, the AC / DC conversion circuit 1 provides 24VDC to the transmitter through the precision ammeter and the corresponding opto-isolation relay.

[0050] (2) If the transmitter to be tested is a pressure transmitter with HART protocol, the HART protocol of the ConsT822 intelligent pressure calibrator and the ConsT811 pressure calibrator can be connected to the signal input terminals 2 and 3 of the current / voltage converter circuit 4 (HART+ is connected to the signal input terminal 2 of the current / voltage converter circuit 4, HART- is connected to the signal input terminal 3 of the current / voltage converter circuit 4, and the input signal terminals 1 and 4 of the current / voltage converter circuit 4 are not used). The signal output of the current / voltage converter circuit 4 is controlled by the changeover switch 2 (each time the switch is changed, only the same signal output terminal with the same switch position provides power to the pressure transmitter). The HART protocol of the pressure calibrator provides 24VDC to the transmitter through the corresponding opto-isolation relay. At the same time, the corresponding current output value of different pressures applied to the transmitter can be detected.

[0051] 3. Temperature transmitter testing:

[0052] First, connect the output of the DC resistor (in this embodiment, a ZX74D type DC resistor) to the signal input (i.e., the second connector) PT1 to PT4 of the RTD converter circuit 3. Connect the power supply terminals of the 8-channel temperature transmitter to the 8-channel signal output terminals of the current / voltage conversion circuit 4. According to the wiring diagram of the temperature transmitter platinum resistance thermometer and the connection between PT1 to PT4 and the DC resistor, remove the platinum resistance thermometer from the temperature transmitter. Replace the platinum resistance thermometer with the 8-channel signal output terminals of the RTD converter circuit 3 and connect them to the 8-channel temperature transmitter respectively.

[0053] (1) The 24VDC output from AC / DC conversion circuit 1 is used to provide 24VDC power to the temperature transmitter:

[0054] Connect a precision ammeter to input terminals 1 and 2 of the current / voltage converter circuit 4 (signal input terminals 3 and 4 of the current / voltage converter circuit 4 are not used). Control the signal output of the current / voltage converter circuit 4 through the changeover switch 2 (each time the switch is changed, only the same signal output terminal with the same switch position provides power to the pressure transmitter). At the same time, the 24VDC power supply provides 24VDC power to the transmitter through the precision ammeter and the corresponding opto-isolation relay. By changing the resistance value of the DC resistor and the position of the changeover switch 2, the current output value of 8 temperature transmitters with the same standard resistance can be checked at the same time.

[0055] (2) If the temperature transmitter supports the HART protocol, the HART protocol of the ConsT822 or ConsT811 pressure calibrator can be used to control the 8-channel signal output of the current / voltage conversion circuit 4 through the changeover switch 2 (to provide 24VDC power to the temperature transmitter):

[0056] Connect the HART protocol output terminal of the pressure calibrator to the signal input terminals 2 and 3 of the current / voltage converter circuit 4 (HART+ is connected to signal input terminal 2 of the current / voltage converter circuit 4, HART- is connected to signal input terminal 3 of the current / voltage converter circuit 4, and input signal terminals 1 and 4 of the current / voltage converter circuit 4 are left unused). Control the signal output of the current / voltage converter circuit 4 through the changeover switch 2 (each time the switch is changed, only the same signal output terminal with the same switch position provides power to the pressure transmitter). The HART protocol signal of the pressure calibrator provides 24VDC to the transmitter through the corresponding opto-isolation relay. At the same time, it can detect the corresponding current output value when different standard resistors are applied to the transmitter.

[0057] 4. Flow computer signal channel detection:

[0058] Using the constant current source function of the ConsT811, eight signal channels of the flow meter can be tested simultaneously, and the signal channels can be calibrated and verified.

[0059] (1) Pressure and differential pressure signal channel detection

[0060] First, correctly connect the pressure channel signal lines (pressure +, pressure - or differential pressure +, differential pressure -) of the 8 flow computers to be tested (the signal transmission is a standard (4-20) mA current signal) to the 8-channel 2-wire power supply lines of the current / voltage conversion circuit 4 signal output. For example, connect V1+ to the positive power supply of the first transmitter and V1- to the negative power supply of the first transmitter, and so on, until V8+ is connected to the positive power supply of the eighth transmitter and V8- is connected to the negative power supply of the eighth transmitter.

[0061] When the pressure and differential pressure signal channels are detected using a ConsT811 constant current source as a standard current signal, such as Figure 4 As shown, the negative (-) power supply of the active current source of the ConsT811 pressure calibrator is connected to terminal 3 of the current / voltage conversion circuit signal input, and the negative (-) current supply is connected to terminal 2 of the current / voltage conversion circuit signal input. Simultaneously, the ConsT811 outputs current and is powered by an internal power supply. Then, the ConsT811 outputs standard currents of 4mA, 8mA, 12mA, 16mA, and 20mA to the pressure (or differential pressure) signal channel. Through switch 2, the pressure and differential pressure signal channels of eight flow computers with the same current value are calibrated / verified respectively until all detection points of the eight flow computer signal pressure signal channels are verified / calibrated.

[0062] (2) Temperature signal channel detection:

[0063] First, correctly connect the temperature channel signal lines (temperature +, temperature -) of the 8 flowmeters to be tested (the signal transmission is a standard (4-20) mA current signal) to the 8 two-wire power lines of the current / voltage conversion circuit 4 signal output. For example, connect V1+ to the positive power supply of the first transmitter and V1- to the negative power supply of the first transmitter, and so on, until V8+ is connected to the positive power supply of the eighth transmitter and V8- is connected to the negative power supply of the eighth transmitter.

[0064] When the temperature signal channel uses a ConsT811 constant current source as a standard current signal for channel detection, such as Figure 5 As shown, the mA+ of the ConsT811 pressure calibrator is connected to the input signal terminal 2 of the current / voltage conversion circuit 4, and the mA- is connected to the signal input terminal 3 of the current / voltage conversion circuit 4. Simultaneously, the ConsT811 outputs current and is powered by an internal power supply. Then, the ConsT811 outputs standard currents of 4mA, 8mA, 12mA, 16mA, and 20mA to the temperature signal channels. Through the selector switch 2, the temperature signal channels of eight flow computers with the same current value are calibrated / verified respectively until all detection points of the eight flow computer temperature signal channels have been calibrated / verified.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-channel detection device suitable for transmitters and flow computers, comprising interconnected detection modules and an AC / DC conversion circuit, characterized in that, The detection module includes a changeover switch and several detection units electrically connected to the changeover switch; The detection unit includes a current / voltage conversion circuit, a thermal resistance conversion circuit, a first connector, and a second connector. The current / voltage conversion circuit and the thermal resistance conversion circuit are electrically connected to each other; the first connector is electrically connected to the current / voltage conversion circuit and is used to connect an external current source; the second connector is electrically connected to the thermal resistance conversion circuit and is used to connect an external DC resistor. The changeover switch is used to switch the detection unit connected to it; The first connector includes three connection ports, and the current / voltage conversion circuit includes a relay switch and positive and negative detection ports for connecting the transmitter under test. Port 1 of the first connector is electrically connected to the changeover switch; The drive coil of the relay switch is electrically connected to the changeover switch, and the two ends of the contacts of the relay switch are electrically connected to port 2 and the positive detection port of the first connector, respectively, and the negative detection port is electrically connected to port 3 of the first connector. The second connector includes n connection ports, and the thermal resistance conversion circuit includes n relay switches and a resistor port for connecting the thermal resistance, where n is an integer greater than 1. The drive coil of the i-th relay switch is electrically connected to the current / voltage conversion circuit corresponding to the detection unit, and the two ends of the contacts of the relay switch are electrically connected to the i-th port and the resistor port of the second connector, respectively, i∈[1,n].

2. The multi-channel detection device suitable for transmitters and flow computers according to claim 1, characterized in that, A protection circuit is provided between the AC / DC conversion circuit and port 1 of the first connector.

3. A multi-channel detection device suitable for transmitters and flow computers according to claim 2, characterized in that, The protection circuit includes a current-limiting resistor and a reverse diode connected in sequence.

4. A multi-channel detection device suitable for transmitters and flow computers according to claim 1, characterized in that, The first connector also includes a spare port.

5. A multi-channel detection device suitable for transmitters and flow computers according to any one of claims 1-4, characterized in that, The relay switch is an opto-isolated relay.

6. A multi-channel detection device suitable for transmitters and flow computers according to claim 1, characterized in that, The line resistance deviation between any two of the detection units is less than 5mΩ.

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