Standard source device for calibrating two-wire system 4-20mA current signal conditioning module

Abstract

The invention relates to a standard source device for calibrating a two-wire system 4-20mA current signal conditioning module. The standard source device comprises an ammeter, a display window, a gear dial selection knob, a wiring port, a resistor and a box body, according to the invention, the defect that the operation of manually adjusting different current values by using a sliding potentiometer is tedious and time-consuming when the two-wire 4-20mA current signal conditioning module is calibrated is overcome, and the rapid and accurate input of a current reference value is also realized through the device. According to the device, key equipment is indispensable when the calibration of the two-wire system 4-20mA current signal conditioning module is completed, and the linearity and accuracy of the measurement of the two-wire system 4-20mA current signal conditioning module are ensured, so that the correctness of data measured in an arc wind tunnel test is ensured, the quality of each data in the test is improved, and the measurement accuracy of the two-wire system 4-20mA current signal conditioning module is improved. And the method plays an important role in data acquisition of an arc wind tunnel test.

Description

Technical Field

[0001] The invention relates to a standard source device for calibrating a two-wire 4-20mA current signal conditioning module. Background Art

[0002] The arc wind tunnel is an effective and indispensable core test equipment for completing the design of thermal protection structural materials for hypersonic aircraft. It can simulate the aerodynamic heating environment of various types of hypersonic aircraft within a certain range and conduct aerodynamic thermal ground simulation tests on test models.

[0003] In the arc wind tunnel equipment, the model surface and the environment of the simulation test need to be measured for temperature, pressure, etc.; when evaluating the parameters of the arc wind tunnel equipment itself, it is also necessary to monitor and accurately measure the various pressure parameters of the arc wind tunnel equipment in real time. These pressure parameters need to be obtained through a high-precision data acquisition system. In the high-precision data acquisition system of the arc wind tunnel test, the on-site test signal is measured and converted by the sensor and enters the on-site signal conditioning terminal box. The measured current signal converted by the signal conditioning box is transmitted to the collector through the signal cable. The accuracy of the signal conditioning module is the front-end conversion device of the high-precision acquisition system, and its accuracy affects the accuracy of the entire data acquisition system. The two-wire 4-20mA current conditioning module is the main device for measuring pressure. The accuracy of the two-wire 4-20mA current conditioning module is the key to determining whether the various pressure parameters are normal or not. In actual use, the two-wire 4-20mA current conditioning module usually has individual module zero point and accuracy inaccuracy during long-term use. The module with inaccurate accuracy will affect the correctness of the test data during the test. Therefore, the calibration of the two-wire 4-20mA current conditioning module is crucial to the acquisition of the pressure parameters of the entire test, and is of great significance to the acquisition and monitoring of the model pressure parameters and arc wind tunnel test equipment parameters in the test. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to propose a standard source device for calibrating a two-wire 4-20mA current signal conditioning module, to input a current reference value simply and quickly, and to ensure the accuracy and stability of the input current reference value, and to overcome the drawbacks of large fluctuations, instability and slow progress in converting the current reference value by manually adjusting the sliding potentiometer.

[0005] The technical solution of the present invention is:

[0006] A standard source device for calibrating a two-wire 4-20mA current signal conditioning module, comprising an ammeter, a display window, a gear dial selection knob, a wiring port, a resistor and a box;

[0007] The front of the box is equipped with a current reference value display window, a gear dial selection knob and a wiring port; the box is equipped with an ammeter and multiple resistors with different resistance values;

[0008] After the current conditioning module to be calibrated is powered by a voltage-stabilized power supply, the wiring port of the standard source device is connected to the input end of the current conditioning module to be calibrated through a signal line, and resistors of different resistance values ​​are connected by switching the gear dial selection knob to change the output current reference value of the standard source device, and the current reference value is measured by an ammeter and displayed in a display window;

[0009] The current reference value is input to the input end of the current conditioning module to be calibrated via a signal line. After conversion by the current conditioning module to be calibrated, an ammeter measures the actual output value at the output end of the current conditioning module to be calibrated. The calibration of the current conditioning module is completed based on the comparison between the actual output value and the current reference value.

[0010] Furthermore, the current conditioning module to be calibrated is a two-wire 4-20mA current signal conditioning module.

[0011] Furthermore, by connecting resistors of different resistance values ​​to form different circuits, the output current reference value of the standard source can be changed.

[0012] Furthermore, the resistors with different resistance values ​​at least include: resistors R1 = 6KΩ, R2 = 3KΩ, R3 = 2KΩ, R4 = 1.5KΩ, and R5 = 1.2KΩ.

[0013] Furthermore, connecting different resistors is achieved by rotating the gear selector knob.

[0014] Furthermore, the standard source device outputs a specific reference current value.

[0015] When loop 1 is connected, that is, resistance R1 = 6KΩ, the output reference current value is 4mA;

[0016] When loop 2 is connected, that is, R2 = 3KΩ, the output reference current value is 8mA;

[0017] When loop 3 is connected, that is, R3 = 2KΩ, the output reference current value is 12mA;

[0018] When loop 4 is connected, that is, R4 = 1.5KΩ, the output reference current value is 16mA;

[0019] When loop 5 is connected, that is, R5 = 1.2KΩ, the output reference current value is 20mA.

[0020] Furthermore, the 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply.

[0021] Furthermore, each output current reference value is accurately measured by an ammeter and displayed in a display window with five and a half digits.

[0022] Furthermore, the accuracy of the output current reference value is within 0.1%.

[0023] Furthermore, the present invention also proposes a two-wire 4-20mA current signal conditioning module calibration method based on the standard source device for calibrating the two-wire 4-20mA current signal conditioning module, and the method comprises the following steps:

[0024] (1) After the 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply, use a signal line to connect the wiring port and the input end of the current conditioning module;

[0025] (2) by switching the gear selector knob, a specific resistor with different resistance values ​​is connected to change the output current reference value of the signal source, and the current reference value is displayed in the display window by the ammeter;

[0026] (3) The output current reference value of the signal source is input to the input end of the current conditioning module through the wiring port and the signal line. After conversion by the current conditioning module, an ammeter is connected to the output end of the current conditioning module, and the actual output current value is measured by the ammeter;

[0027] (4) The calibration process of the current conditioning module is completed by comparing the actual output current value with the current reference value; if the output current value is consistent with the reference current value, the measurement of the calibrated two-wire 4-20mA current conditioning module is normal; if the output current value is different from the reference current value, the zero point and full scale potentiometer of the two-wire 4-20mA current conditioning module are adjusted multiple times to make the output current value consistent with the reference current value, so as to achieve the purpose of calibrating the two-wire 4-20mA current conditioning module, thereby ensuring the accuracy of the two-wire 4-20mA current conditioning module.

[0028] The beneficial effects of the present invention compared with the prior art are:

[0029] (1) The present invention realizes a simple and quick input current reference value during calibration of a two-wire 4-20mA current signal conditioning module, and ensures the accuracy and stability of the input current reference value, thereby overcoming the drawbacks of large fluctuations, instability, and slow progress in converting the current reference value by manually adjusting the sliding potentiometer.

[0030] (2) The device of the present invention saves the time for calibration of the signal conditioning module, improves the work efficiency of the calibration personnel, and thus improves the efficiency of the entire test.

[0031] (3) The device of the present invention is an indispensable key equipment for completing the calibration of the two-wire 4-20mA current signal conditioning module, which ensures the linearity and accuracy of the measurement of the two-wire 4-20mA current conditioning module, thereby ensuring the accuracy of the high-precision data acquisition system of the arc wind tunnel test, and plays an important role in the data acquisition of the arc wind tunnel test.

[0032] (4) The present invention realizes fast and accurate input of current reference value, and changes the given reference current signal through the gear dial selection knob, which saves the time of signal conditioning module calibration and improves work efficiency.

[0033] (5) The device of the present invention has a simple and portable structure and is convenient and easy to implement when a current reference value is given. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the structural outline diagram of the standard source device;

[0035] Figure 2 is a schematic diagram of the standard source device;

[0036] Figure 3 The schematic diagram of the calibration of the reference value output by the standard source device. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0038] During the calibration process of the two-wire 4-20mA current signal conditioning module, due to the special power supply of the two-wire 4-20mA current signal conditioning module, using our conventional standard source may cause internal damage to the standard source due to the power supply. In order to prevent the destruction of the signal standard source, a special current signal standard source needs to be developed.

[0039] The present invention proposes a standard source device for calibrating a two-wire 4-20mA current signal conditioning module, which is mainly composed of a high-precision ammeter, a resistor with a specific resistance value, a gear dial selection knob, and a wiring port. The device is an integrated box body consisting of a high-precision ammeter and resistors with different resistance values, and the front of the box body is provided with a resistor gear dial selection knob, a wiring port, and a current reference value display window. After the 4-20mA two-wire current conditioning module to be calibrated is powered by a voltage-stabilized power supply, the wiring port of the device is connected to the input end of the module via a signal line, and the circuit is in a connected state. By switching the gear dial selection knob, specific resistors with different resistance values ​​are connected to change the output current reference value of the signal source, and the circuit reference value is displayed in the display window by the high-precision ammeter.

[0040] Specifically, Figure 1As shown, a standard source device for calibrating a two-wire 4-20mA current signal conditioning module proposed by the present invention comprises an ammeter 1, a display window 2, a gear dial selection knob 3, a wiring port 4, a resistor 5 and a box;

[0041] The front of the box is equipped with a current reference value display window 2, a gear dial selection knob 3 and a wiring port 4; an ammeter 1 and a plurality of resistors 5 with different resistance values ​​are arranged inside the box;

[0042] After the current conditioning module to be calibrated is powered by a voltage-stabilized power supply, the connection port 4 of the standard source device is connected to the input end of the current conditioning module to be calibrated through a signal line, and the resistor 5 with different resistance values ​​is switched on by switching the gear dial selection knob 3 to change the output current reference value of the standard source device, and the current reference value is measured by the ammeter 1 and displayed in the display window 2;

[0043] The current reference value is input to the input end of the current conditioning module to be calibrated via the signal line. After being converted by the current conditioning module to be calibrated, the actual output value is measured by the ammeter 1 at the output end of the current conditioning module to be calibrated. The calibration of the current conditioning module is completed based on the comparison between the actual output value and the current reference value.

[0044] Furthermore, the current conditioning module to be calibrated is a two-wire 4-20mA current signal conditioning module.

[0045] Furthermore, by connecting resistors 5 with different resistance values ​​to form different loops, the output current reference value of the standard source can be changed.

[0046] like Figure 2 As shown, the resistors with different resistance values ​​at least include: resistors R1 = 6KΩ, R2 = 3KΩ, R3 = 2KΩ, R4 = 1.5KΩ, and R5 = 1.2KΩ.

[0047] Furthermore, connecting different resistors is achieved by rotating the gear selector knob.

[0048] Furthermore, the standard source device outputs a specific reference current value.

[0049] When loop 1 is connected, that is, resistance R1 = 6KΩ, the output reference current value is 4mA;

[0050] When loop 2 is connected, that is, R2 = 3KΩ, the output reference current value is 8mA;

[0051] When loop 3 is connected, that is, R3 = 2KΩ, the output reference current value is 12mA;

[0052] When loop 4 is connected, that is, R4 = 1.5KΩ, the output reference current value is 16mA;

[0053] When loop 5 is connected, that is, R5 = 1.2KΩ, the output reference current value is 20mA.

[0054] Furthermore, the 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply.

[0055] Furthermore, each output current reference value is accurately measured by an ammeter and displayed in a display window with five and a half digits.

[0056] Furthermore, the accuracy of the output current reference value is within 0.1%.

[0057] like Figure 3 As shown, the present invention also proposes a two-wire 4-20mA current signal conditioning module calibration method based on the standard source device for calibrating the two-wire 4-20mA current signal conditioning module, and the method includes the following steps:

[0058] (1) After the 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply, use a signal line to connect the wiring port and the input end of the current conditioning module;

[0059] (2) by switching the gear selector knob, a specific resistor with different resistance values ​​is connected to change the output current reference value of the signal source, and the current reference value is displayed in the display window by the ammeter;

[0060] (3) The output current reference value of the signal source is input to the input end of the current conditioning module through the wiring port and the signal line. After conversion by the current conditioning module, an ammeter is connected to the output end of the current conditioning module, and the actual output current value is measured by the ammeter;

[0061] (4) The calibration process of the current conditioning module is completed by comparing the actual output current value with the current reference value; if the output current value is consistent with the reference current value, the measurement of the calibrated two-wire 4-20mA current conditioning module is normal; if the output current value is different from the reference current value, the zero point and full scale potentiometer of the two-wire 4-20mA current conditioning module are adjusted multiple times to make the output current value consistent with the reference current value, so as to achieve the purpose of calibrating the two-wire 4-20mA current conditioning module, thereby ensuring the accuracy of the two-wire 4-20mA current conditioning module.

[0062] The present invention solves the cumbersome and time-consuming drawback of manually adjusting different current values ​​using a sliding potentiometer during calibration of a two-wire 4-20mA current signal conditioning module, and also realizes a fast and accurate input current reference value through the device. The device is an indispensable key device when completing the calibration of a two-wire 4-20mA current signal conditioning module, ensuring the linearity and accuracy of the measurement of the two-wire 4-20mA current conditioning module, thereby ensuring the correctness of the data measured in the arc wind tunnel test, not only improving the quality of various data in the test, but also playing an important role in the data collection of the arc wind tunnel test.

[0063] Parts of the present invention that are not described in detail belong to common knowledge among those skilled in the art.

Claims

1. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module, characterized in that: It comprises an ammeter (1), a display window (2), a gear position dial selection knob (3), a wiring port (4), a resistor (5) and a box; A current reference value display window (2), a gear position dial selection knob (3) and a wiring port (4) are installed on the front of the box; an ammeter (1) and a plurality of resistors (5) with different resistance values ​​are arranged inside the box; After the current conditioning module to be calibrated is powered by a voltage-stabilized power supply, the connection port (4) of the standard source device is connected to the input end of the current conditioning module to be calibrated via a signal line, and resistors (5) of different resistance values ​​are switched on by switching the gear dial selection knob (3) to change the output current reference value of the standard source device, and the current reference value is measured by an ammeter (1) and displayed on a display window (2); The current reference value is input to the input end of the current conditioning module to be calibrated via a signal line, and after being converted by the current conditioning module to be calibrated, an ammeter (1) measures the actual output value at the output end of the current conditioning module to be calibrated, and the calibration of the current conditioning module is completed based on the comparison between the actual output value and the current reference value.

2. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: The current conditioning module to be calibrated is a two-wire 4-20mA current signal conditioning module.

3. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: By connecting resistors (5) of different resistance values ​​to form different circuits, the output current reference value of the standard source can be changed.

4. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: The resistors with different resistance values ​​at least include: resistors R1 = 6KΩ, R2 = 3KΩ, R3 = 2KΩ, R4 = 1.5KΩ, and R5 = 1.2KΩ.

5. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 4, characterized in that: Connecting different resistors is achieved by turning the gear selector knob.

6. A standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 4, characterized in that: The standard source device outputs a specific reference current value, When loop 1 is connected, that is, resistance R1 = 6KΩ, the output reference current value is 4mA; When loop 2 is connected, that is, R2 = 3KΩ, the output reference current value is 8mA; When loop 3 is connected, that is, R3 = 2KΩ, the output reference current value is 12mA; When loop 4 is connected, that is, R4 = 1.5KΩ, the output reference current value is 16mA; When loop 5 is connected, that is, R5 = 1.2KΩ, the output reference current value is 20mA.

7. The standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: The 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply.

8. The standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: The current reference value of each output is accurately measured by the ammeter and displayed in the display window with five and a half digits.

9. The standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to claim 1, characterized in that: The output current reference value is accurate within 0.1%.

10. A calibration method for a two-wire 4-20mA current signal conditioning module implemented based on the standard source device for calibrating a two-wire 4-20mA current signal conditioning module according to any one of claims 1 to 9, characterized in that include: (1) After the 4-20mA two-wire current conditioning module to be calibrated is powered by a DC24V regulated power supply, use a signal line to connect the wiring port and the input end of the current conditioning module; (2) by switching the gear selector knob, a specific resistor with different resistance values ​​is connected to change the output current reference value of the signal source, and the current reference value is displayed in the display window by the ammeter; (3) The output current reference value of the signal source is input to the input end of the current conditioning module through the wiring port and the signal line. After conversion by the current conditioning module, an ammeter is connected to the output end of the current conditioning module, and the actual output current value is measured by the ammeter; (4) The calibration process of the current conditioning module is completed by comparing the actual output current value with the current reference value; if the output current value is consistent with the reference current value, the measurement of the calibrated two-wire 4-20mA current conditioning module is normal; if the output current value is different from the reference current value, the zero point and full scale potentiometer of the two-wire 4-20mA current conditioning module are adjusted multiple times to make the output current value consistent with the reference current value, so as to achieve the purpose of calibrating the two-wire 4-20mA current conditioning module, thereby ensuring the accuracy of the two-wire 4-20mA current conditioning module.

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