Spacecraft vacuum thermal test thermocouple insulation fault diagnosis instrument and diagnosis method thereof

Abstract

The application provides a spacecraft vacuum thermal test thermocouple insulation fault diagnosis instrument and a diagnosis method thereof. The resistance between the first conductor and the second conductor of the thermocouple with poor insulation and the structure ground is measured and compared through the measuring end, and the position of the poor insulation fault point from the first conductor or the second conductor of the thermocouple is calculated according to the comparison result. The diagnosis result has high confidence and high fault positioning accuracy.

Description

Technical Field

[0001] This invention relates to the field of thermal measurement in spacecraft ground tests, and more specifically, to a diagnostic instrument and method for diagnosing thermocouple insulation faults in spacecraft vacuum thermal tests. Background Technology

[0002] Thermocouples are commonly used as the primary temperature measuring element in spacecraft vacuum thermal tests. The tests are conducted inside a vacuum chamber. After the thermocouples are attached, the wire bundles are led out, and the welded connectors are transferred outside the chamber via flanges on the chamber wall. During inspections, poor insulation between the thermocouples and the structural ground (i.e., continuity between the thermocouple circuit and the chamber wall) is frequently encountered. If this fault is not addressed promptly, subsequent tests after the chamber is closed may result in inaccurate or unstable temperature data, or even serious consequences such as open circuits and interrupted temperature measurement due to lack of signal. Therefore, it is essential to investigate and address thermocouple insulation problems before the start of the test.

[0003] After thermocouple harnesses are integrated, they are routed on the surface of spacecraft or payload structures. The length of thermocouples in large spacecraft can even reach 15m. It is time-consuming and laborious to troubleshoot faulty thermocouples along their entire length. For thermocouples bundled together with other harnesses, it is even more difficult to find a solution.

[0004] Patent document CN108225615A discloses a patent application filed by Rosemount Corporation of the United States for a temperature transmitter assembly for short-circuit thermocouple diagnostics. This assembly determines the resistance of the thermocouple and, based on the determined resistance, provides an indication of whether the first and second conductors are short-circuited together before the junction. The assembly provides this indication by determining that the measured thermocouple resistance is less than the baseline resistance minus the resistance of the second portion. This is not applicable to scenarios involving short circuits between the thermocouple and the tank wall during spacecraft vacuum thermal testing.

[0005] Patent document CN102901586A discloses a thermocouple anomaly detection system applied for by Toshiba Equipment and Systems, Ltd. of Japan. This system detects anomalies in each of the plurality of thermocouples by comparing the transmitted signals obtained from the multiple thermocouple wires installed in each thermocouple. While this patent document can detect anomalies, it cannot pinpoint the location of the fault.

[0006] Patent document CN104807553A discloses a self-diagnostic thermocouple patent applied for by Ningbo Aoqi Instrument Complete Equipment Co., Ltd. The positive and negative terminals of the thermocouple form a closed loop. A common electrode, a different conductor from the positive and negative terminals, is connected to the junction of the measuring ends of the positive and negative terminals. The common electrode, together with the positive and negative terminals, forms a closed loop. A transmitter is connected to each loop. The transmitter converts the thermoelectric potential in the loop into a temperature value and inputs it to a processor. The processor compares the measured values ​​in the three loops. If the three values ​​differ, it indicates that the electrodes in the loop have deteriorated. The processor can also output the magnitude of the difference. When the difference exceeds a preset range, the thermocouple is considered to have failed, thus enabling online real-time monitoring. While the aforementioned diagnostic instrument can test the accuracy of thermocouple temperature measurement and diagnose thermocouple deterioration, it cannot pinpoint the location of the fault. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a diagnostic instrument and method for thermocouple insulation faults in spacecraft vacuum thermal testing.

[0008] A method for diagnosing thermocouple insulation faults in a spacecraft vacuum thermal test, provided by the present invention, includes: The resistance between the first and second conductors of the thermocouple with poor insulation is measured and compared with the structural ground through the measuring end. Based on the comparison, the position of the poor insulation fault point from the measuring end of the first or second conductor of the thermocouple is calculated.

[0009] Preferably, for a thermocouple circuit with freezing point compensation, the resistance values ​​measured between the H terminal of the first conductor of the connected thermocouple, the L terminal of the second conductor of the connected thermocouple, and the G terminal of the structural ground of the connected thermocouple measurement object are respectively... , ; First scenario: (3) , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; This indicates the resistance value of the freezing point thermocouple used for freezing point compensation in the thermocouple circuit; The fault point is then diagnosed in the first conductor: (6) This indicates the distance from the fault point to the measuring end H; The second scenario: (7)

[0010] This represents the resistance value from the fault point to the instrument's measurement point G; The fault point is then diagnosed in the second conductor: (9) This indicates the distance from the fault point to the measuring terminal L; The third scenario: (10) The fault point is then diagnosed at the joint between the first and second conductors, i.e.: (11).

[0011] Preferably, for a thermocouple circuit without freezing point compensation, the resistance values ​​measured between the H terminal of the first conductor of the connected thermocouple, the L terminal of the second conductor of the connected thermocouple, and the G terminal of the structural ground of the connected thermocouple measurement object are respectively... , ; First scenario: (13) , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; The fault point is then diagnosed in the first conductor: (16) This indicates the distance from the fault point to the measuring end H; The second scenario: (14) The fault point is then diagnosed in the second conductor: (17) This indicates the distance from the fault point to the measuring terminal L; The third scenario: (15) The fault point is then diagnosed at the joint between the first and second conductors, i.e.: (11).

[0012] According to the present invention, a spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument includes a test and analysis circuit, a thermocouple connection socket, and a structural ground connection socket. The thermocouple connection socket includes the H end of the first conductor of the connected thermocouple and the L end of the second conductor of the connected thermocouple. The structural connection socket includes the G terminal of the structural ground of the connected thermocouple measurement object; The test and analysis circuit calculates the location of the insulation fault based on the resistance values ​​between the H and G terminals, the resistance values ​​between the L and G terminals, and the set resistance linear density values ​​of the first and second conductors that make up the thermocouple. It is applicable to fault diagnosis of short circuits between thermocouples and tank walls in spacecraft vacuum thermal tests.

[0013] Preferably, the aforementioned spacecraft vacuum thermal test thermocouple insulation fault diagnosis method is used to calculate the position of the insulation failure point from the measuring end of the first or second conductor of the thermocouple.

[0014] Preferably, the voltages at terminals H and L are automatically measured relative to terminal G, and compared with the voltage divider voltages of the internally connected series resistors to obtain the resistance values ​​at terminals H and L relative to terminal G. , By comparing the difference between the two resistance values ​​with... The size of the fault is determined by first diagnosing whether the fault is located in the first conductor or the second conductor, then calculating the fault location and outputting it to the LCD display module.

[0015] According to the present invention, a method for using a spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument is characterized in that, when performing thermocouple fault diagnosis, the resistance and insulation of thermocouples connected to the same connector are measured once to identify the thermocouple with insulation problems; the H-end lead is connected to the positive terminal of the thermocouple, the L-end lead is connected to the negative terminal of the thermocouple, and the G-end lead is connected to the structural ground of the thermocouple measurement object.

[0016] Preferably, the toggle switch is activated to start measurement and diagnosis, and the location of the insulation failure is output on the screen after the measurement results are analyzed and calculated.

[0017] Preferably, measuring instruments are used to troubleshoot faulty thermocouples, check the insulation resistance between each thermocouple and the structural ground, and compare the resistance values. The thermocouple with the smallest insulation resistance value is considered to be the faulty thermocouple.

[0018] Preferably, the H and L terminal interface leads are connected in parallel, and the loop resistance is zeroed; the H, L, and G terminals are respectively connected to the structural ground formed by the first conductor lead, the second conductor lead, and the vacuum tank wall of the faulty thermocouple; and input sequentially. , , , The value is determined; the resistance is measured and analyzed; the fault location is output.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention is easy to carry, highly efficient in diagnosis, and suitable for fault location of thermocouple insulation problems in spacecraft vacuum thermal tests, with an error within 0.1m.

[0020] 2. This invention solves the problem of diagnosing short-circuit faults between thermocouples and tank walls in spacecraft vacuum thermal tests.

[0021] 3. The present invention has the advantages of high confidence in diagnostic results and high accuracy in fault location. Attached Figure Description

[0022] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the instrument panel of the present invention.

[0023] Figure 2 This is a schematic diagram of the probe connection of the present invention.

[0024] Figure 3 This is a schematic diagram of the diagnostic principle circuit of the present invention.

[0025] Figure 4 This is a flowchart of the processor diagnostic process in the instrument of this invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0027] According to the present invention, a spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument is provided. The instrument mainly consists of the following parts: a power supply assembly, a test and analysis circuit, a thermocouple connection socket, a structural ground connection socket, and an LCD screen output assembly. All of these parts are integrated within the instrument housing. The positive and negative terminals of the thermocouple under test are connected to the structural ground via an adapter copper wire connected to the socket.

[0028] When starting the diagnosis, the resistance values ​​between the two poles of the thermocouple (the first conductor and the second conductor) and the structural ground are collected separately. Then, the resistance linear density values ​​of the two conductors that make up the thermocouple are analyzed and input into the processor. The processor analyzes and calculates the location of the insulation fault and outputs the diagnosis results.

[0029] Its fault location analysis principle is as follows: By inputting the resistance linear density and total length of the first and second conductors of the thermocouple, the resistance between the first and second conductors of the thermocouple with poor insulation and the structural ground is measured and compared. The resistance between the point of poor insulation and the measuring ends of the thermocouple can be calculated, and the location of the fault point from the measuring ends can be obtained. The specific diagnostic principle is as follows: a) Let the linear resistance densities of the first and second conductors of the thermocouple be respectively... , The total length of the thermocouple is The lengths of the first and second conductors are both The total resistance of the thermocouple circuit is ; b) The resistance values ​​between terminal H (connected to the first conductor), terminal L (connected to the second conductor), and terminal G were measured using instruments. , Let the resistance from the fault point to the instrument measurement point G be denoted as . If the thermocouple circuit includes freezing point compensation, let the resistance of the freezing point thermocouple be... , ; This indicates the resistance of the first conductor of the freezing point thermocouple. To describe the resistance of the second conductor of a freezing point thermocouple, see [link to relevant documentation]. Figure 3 .

[0030] c) If the fault point is on the first conductor, let the distance from the fault point to the measuring terminal H be... If the fault point is on the second conductor, let the distance from the fault point to the measuring terminal L be... Based on the above data analysis, the following equations can be derived (taking the circuit containing freezing point compensation as an example): (1) It can be calculated that: (2) There are three possible scenarios: In the first case, when: (3) The instrument diagnoses the fault in the first conductor section, which is... (4) We can obtain: (5) Right now: (6) In the second scenario, when: (7) The instrument diagnoses the fault in the second conductor section, which is... (8) We can obtain: (9) The third scenario is when: (10) The instrument diagnoses the fault point near the solder joint between the first and second conductors, namely: (11) If the circuit does not contain freezing point compensation, i.e. ,but: Equation (1) is changed to (12): (12) Criteria (3), (7), and (10) are respectively changed to (13), (14), and (15): (13) (14) (15) Fault location expressions (6) and (9) are changed to (16) and (17): (16) (17) The fault location expression (11) remains unchanged.

[0031] The logic executed by the instrument's internal processor is as follows: The system automatically measures the voltage at terminals H, L, and G, and compares this voltage with the voltage divider voltage of the internally connected series resistor to obtain the resistance values ​​at terminals H, L, and G. and By comparing the difference between the two resistance values ​​with... The size of the fault is determined by first diagnosing whether the fault is located in the first or second conductor, and then calculating the fault location according to equations (1) and (2), and outputting it to the LCD display module.

[0032] The preferred configuration for the main buttons and functions of the panel of the thermocouple insulation fault diagnostic instrument for spacecraft vacuum thermal testing is as follows: RESET: Clears the underlying data stored in the processor. , , , ); ON / OFF: Instrument switch button; M1, M2, M3: Recall the three pre-stored basic data groups ( , , , ); RSET: Zeroing the circuit resistance reference; Left and right arrow keys: Adjust the position of the input data; Up and down arrow keys: Adjust the size of the input data; START / ENTER: Start the diagnostic procedure / confirm the input; H, G, L: Sockets for connecting the first conductor of the faulty thermocouple, structural ground, and the second conductor of the faulty thermocouple.

[0033] When using the instruments and equipment of this invention to diagnose and locate faults, the following steps are involved: Step 1: Use measuring instruments to troubleshoot faulty thermocouples. Check the insulation resistance between each thermocouple and the structural ground, and compare the resistance values. Usually, the thermocouple with the lowest insulation resistance is the faulty thermocouple. Step 2: Press the ON / OFF button on the instrument panel of this invention to turn on the instrument; Step 3: Connect the H and L interface leads together, press the RSET key, and adjust the circuit resistance to zero; Step 4: Reliably connect H, L, and G to the first conductor lead, the second conductor lead, and the structural ground (vacuum tank wall) of the faulty thermocouple, respectively; Step 5: Press the START / ENTER key, and the screen will prompt you to enter the following information in sequence. , , , In this embodiment, the resistance of the 0.2mm diameter thermocouple copper wire (first conductor) is approximately 0.5889Ω / m, the resistance of the 0.2mm diameter thermocouple constantan wire (second conductor) is approximately 15.2789Ω / m, the total length of the thermocouple is 12.5m, and the resistance of the freezing point thermocouple is 57.1241Ω. , , , The values ​​are 0.5889, 15.2789, 12.5, and 57.1241. Use the left and right arrow keys to adjust the position of the numbers and the up and down arrow keys to adjust the size of the numbers. Press START / ENTER to confirm each input. The default units are Ω / m, Ω / m, m, and Ω. Step 6: After inputting the data, the instrument begins measuring and analyzing the resistance value according to the diagnostic logic; Step 7: Output the fault location, such as H: 4.75, which means that the fault location is about 4.75m inward from the H probe position.

[0034] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for diagnosing thermocouple insulation faults in spacecraft vacuum thermal tests, characterized in that, include: The resistance between the first and second conductors of the thermocouple with poor insulation and the structural ground is measured and compared through the measuring end. The position of the poor insulation fault point from the measuring end of the first or second conductor of the thermocouple is calculated according to the comparison. For a thermocouple circuit with freezing point compensation, the resistance values ​​measured between the H terminal of the first conductor of the connected thermocouple, the L terminal of the second conductor of the connected thermocouple, and the G terminal of the structural ground of the object being measured by the connected thermocouple are respectively... , ; First scenario: （3） , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; This indicates the resistance value of the freezing point thermocouple used for freezing point compensation in the thermocouple circuit; The fault point is then diagnosed in the first conductor: （6） This indicates the distance from the fault point to the measuring end H; The second scenario: （7） This represents the resistance value from the fault point to the instrument's measurement point G; The fault point is then diagnosed in the second conductor: （9） This indicates the distance from the fault point to the measuring terminal L; The third scenario: （10） The fault point is then diagnosed at the joint between the first and second conductors, i.e.: （11）。 2. The method for diagnosing thermocouple insulation faults in spacecraft vacuum thermal tests according to claim 1, characterized in that, For a thermocouple circuit without freezing point compensation, the resistance values ​​measured between the H terminal of the first conductor of the connected thermocouple, the L terminal of the second conductor of the connected thermocouple, and the G terminal of the structural ground of the object being measured by the connected thermocouple are respectively... , ; First scenario: （13） , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; The fault point is then diagnosed in the first conductor: （16） This indicates the distance from the fault point to the measuring end H; The second scenario: （14） The fault point is then diagnosed in the second conductor: （17） This indicates the distance from the fault point to the measuring terminal L; The third scenario: （15） The fault point is then diagnosed at the joint between the first and second conductors, i.e.: （11）。 3. A spacecraft vacuum thermal test thermocouple insulation fault diagnosis instrument, characterized in that, Using the spacecraft vacuum thermal test thermocouple insulation fault diagnosis method according to any one of claims 1 to 2, calculations are performed to obtain the position of the insulation failure point from the measuring end of the first or second conductor of the thermocouple. This includes test and analysis circuits, thermocouple connection sockets, and structural ground connection sockets; The thermocouple connection socket includes the H end of the first conductor of the connected thermocouple and the L end of the second conductor of the connected thermocouple. The structural connection socket includes the G terminal of the structural ground of the connected thermocouple measurement object; The test and analysis circuit calculates the location of the insulation fault based on the resistance values ​​between the H and G terminals, the resistance values ​​between the L and G terminals, and the set resistance linear density values ​​of the first and second conductors that make up the thermocouple. It is applicable to fault diagnosis of short circuits between thermocouples and tank walls in spacecraft vacuum thermal tests.

4. The spacecraft vacuum thermal test thermocouple insulation fault diagnosis instrument according to claim 3, characterized in that, The system automatically measures the voltage between terminals H and L and terminal G, and compares this voltage with the voltage divider voltage of the internal series resistor to obtain the resistance values ​​between terminals H and L and terminal G. , By comparing the difference between the two resistance values ​​with... The size of the fault is determined by first diagnosing whether the fault is located in the first conductor or the second conductor, then calculating the fault location and outputting it to the LCD display module. , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; This indicates the resistance value of the freezing point thermocouple used for freezing point compensation in the thermocouple circuit.

5. A method of using a spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument according to any one of claims 3 to 4, characterized in that, When diagnosing thermocouple faults, first measure the resistance and insulation of the thermocouples connected to the same connector to identify the thermocouple with poor insulation. Then connect the H-terminal lead to the positive terminal of the thermocouple, the L-terminal lead to the negative terminal of the thermocouple, and the G-terminal lead to the structural ground of the thermocouple being measured.

6. The method of using the spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument according to claim 5, characterized in that, The toggle switch initiates measurement and diagnosis. After analyzing and calculating the measurement results, the location of the insulation failure is output on the screen.

7. The method of using the spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument according to claim 5, characterized in that, Use measuring instruments to troubleshoot faulty thermocouples, check the insulation resistance between each thermocouple and the structural ground, and compare the resistance values. The thermocouple with the lowest insulation resistance is considered the faulty thermocouple.

8. The method of using the spacecraft vacuum thermal test thermocouple insulation fault diagnostic instrument according to claim 7, characterized in that, Connect the H and L terminal leads together in parallel and adjust the circuit resistance to zero; connect the H, L, and G terminals to the structural ground formed by the first conductor lead, the second conductor lead, and the vacuum tank wall of the faulty thermocouple, respectively; input the following in sequence. , , , The value is determined; the resistance is measured and analyzed; the fault location is output. , These represent the linear resistance densities of the first and second conductors of the thermocouple, respectively. This represents the total length of the thermocouple, with the lengths of the first and second conductors both being [length missing]. ; This indicates the resistance value of the freezing point thermocouple used for freezing point compensation in the thermocouple circuit.

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