PCDU automatic impedance test system and method based on DAQ970

Abstract

The invention relates to a PCDU automatic impedance testing system and method based on DAQ970, belongs to the technical field of spaceflight electronic testing, and designs a PCDU automatic impedance testing system and method based on DAQ970, and belongs to the technical field of spaceflight electronic testing. The system comprises a DAQ970A data acquisition unit, an extensible switch matrix, a dynamic compensation correction circuit and an upper computer software platform. A to-be-tested channel is gated through the switch matrix, after the DAQ970A collects original impedance data, the impedance error of a test path is eliminated in real time through the dynamic compensation correction circuit, and automatic test process control and data interpretation are achieved through upper computer software. According to the invention, the problems of low efficiency and poor precision of the traditional manual test are solved, the milliohm-level impedance test of more than 120 cores and multiple interfaces is supported, the error is less than or equal to 0.1 m omega, the test rate reaches 40 channels per second, and the quality verification efficiency of the spacecraft power supply system is obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of aerospace electronic testing technology, specifically relating to an automated impedance testing system and method for PCDU based on DAQ970. Background Technology

[0002] Impedance testing of the spacecraft's power control and distribution unit (PCDU) is a critical step in ensuring the reliability of its electrical connections. Traditional testing methods rely on manual operation of a multimeter or manual switching of test points, which has the following problems: 1. Low efficiency: Manual data recording is time-consuming and cannot meet the needs of batch testing of aerospace products.

[0003] 2. Insufficient accuracy: Impedance errors introduced by long test cables and test multimeters are difficult to eliminate, resulting in milliohm-level test errors. 3. Poor scalability: The existing equipment has a limited number of channels, which cannot meet the complex testing requirements of PCDU with multiple interfaces. Summary of the Invention The purpose of this invention is to provide an automated impedance testing system and method for PCDU based on DAQ970. By combining high-precision acquisition, dynamic compensation correction, and multi-channel switching technology, it significantly improves testing efficiency and accuracy. It is simple to apply, highly versatile, greatly enhances testing efficiency, effectively shortens the development cycle, and is very suitable for impedance testing of large quantities of satellite power system control units.

[0004] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions: An automated impedance testing system for PCDUs based on DAQ970 is used for automatic impedance testing of PCDUs. Its features include a data acquisition unit, an expandable switch matrix, a dynamic compensation and correction circuit, and a host computer software platform. The data acquisition unit is used to receive control signals sent by the host computer software platform, send control signals to the expandable switch matrix, acquire PCDU impedance data through the expandable switch matrix, and send it to the dynamic compensation and correction circuit. The expandable switch matrix is ​​used to receive control signals sent by the host computer software platform, configure parameters according to the control signals sent by the expandable switch matrix, connect the data acquisition unit and the PCDU, and transmit the PCDU impedance data to the data acquisition unit. The dynamic compensation and correction circuit is used to receive control signals sent by the host computer software platform, receive PCDU impedance data sent by the data acquisition unit, correct the PCDU impedance data according to the impedance error between the test cable and the expandable switch matrix, and send it to the host computer software platform. The host computer software platform is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit for interpretation and storage; it is also used to send control signals to the data acquisition unit, the expandable switch matrix and the dynamic compensation and correction circuit to realize test process control.

[0005] The data acquisition unit has a built-in ½-digit high-precision digital multimeter, which can perform 20-channel 2-wire high-impedance testing and 10-channel 4-wire low-impedance testing.

[0006] The expandable switch matrix adopts a plug-in relay structure, with each board supporting 40 channels of independent selection, and can meet the multi-interface requirements of the PCDU through backplane expansion.

[0007] The backplane expansion interface of the expandable switch matrix adopts a daisy-chain topology, supports multi-board cascading, and the maximum number of channels for a single collector is ≥40.

[0008] The host computer software platform is also used for setting impedance criteria and classifying and saving error information.

[0009] The host computer software platform includes a test task configuration module, a real-time data display module, and a fault diagnosis module, wherein... The test task configuration module is used to import test point sequences and control signals to the data acquisition unit, expandable switch matrix, and dynamic compensation and correction circuit. The real-time data display module is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit and display the impedance change trend. The fault diagnosis module is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit, and locate problems such as poor cable contact or relay failure based on abnormal data.

[0010] The error correction method of the dynamic compensation correction circuit is as follows: input the length and line type parameters of the test cable; calculate the total impedance error of the test path based on the impedance model of the test cable and the internal resistance data of the switch matrix; superimpose the reverse compensation value on the PCDU impedance data and output the corrected impedance data.

[0011] An automated impedance testing method for PCDU based on DAQ970, using the aforementioned testing system, specifically includes the following steps: (1) Initialization configuration: According to the test requirements and interface definition of PCDU single unit, configure the acquisition settings of data acquisition unit, define the corresponding resistance range of each point, and configure the corresponding acquisition time on the host computer software platform according to the definition of whether the electrical connector point is inductive or capacitive impedance. (2) Input the parameters and impedance criterion threshold of the automated impedance test cable, and set the automatic or manual test mode through the host computer software platform; (3) The expandable switch matrix selects the channel to be tested according to the instruction, and the data acquisition unit acquires PCDU impedance data according to the preset range. The path impedance error is calculated synchronously through the dynamic compensation and correction circuit and dynamically corrected. (4) Compare the corrected PCDU impedance data obtained in step (3) with the preset criteria on the host computer software platform. If the result is qualified, mark it as "pass". If the result is abnormal, generate an independent error file and trigger an alarm. (5) The corrected PCDU impedance data is stored in CSV or database format; (6) Change the test parameters and repeat steps (1) to (5) multiple times. Summarize the impedance test results of different stages in the development of the same PCDU or the impedance test results of multiple single units of the same batch of satellite models, and judge whether the test data is consistent on the host computer software platform.

[0012] In step (2), the impedance criterion threshold is a two-point impedance difference ≤ 0.1Ω or a single-point impedance ≥ 10MΩ.

[0013] In step (2), the channel scanning rate is 40 channels / second, and marked faulty channels are skipped.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention achieves high-precision dynamic compensation by real-time correction of the impedance of the cable and switch matrix, reducing the test error to below 0.1mΩ, which meets the milliohm level test requirements of aerospace.

[0015] (2) This invention combines an expandable switch matrix to achieve high-efficiency testing of multiple channels, covering 120+ interfaces in a single test, with a scanning rate of 40 channels / second, improving efficiency by 90%. (3) The host computer software of the present invention integrates self-test and fault diagnosis functions, avoids the risks of manual operation, supports high voltage test protection mechanism, and prevents equipment damage. Attached Figure Description

[0016] Figure 1 This is a basic structural diagram of the automated impedance testing system of the present invention.

[0017] Figure 2 This is a flowchart of the automated impedance testing process of the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, the automated impedance testing system of the present invention includes: DAQ970A Data Acquisition Unit: As the main control device, it has a built-in ½-digit high-precision digital multimeter, supports multiplexing modules, realizes 20-channel 2-wire high-impedance testing and 10-channel 4-wire low-impedance testing, with a basic DCV accuracy of 0.003%, and acquires PCDU impedance data through a switch matrix. Expandable switch matrix: It adopts a plug-in card relay structure, and a single board supports 40 channels of independent selection. It can be expanded through the backplane to meet the multi-interface requirements of PCDU, and the parameters can be configured through the data acquisition unit.

[0019] Dynamic compensation and correction circuit: It integrates a high-precision AD acquisition and data processing unit. After inputting the cable length and specifications, it automatically calculates the impedance error between the cable and the switch matrix, and corrects the raw data obtained by the DAQ970A data acquisition unit in real time.

[0020] The host computer software platform is developed based on LabVIEW or Python to realize automated control of the test process, data interpretation and storage, and supports impedance criterion settings (such as two-point impedance ≤0.1Ω) and error information classification and saving.

[0021] The dynamic compensation and correction circuit achieves error correction through the following steps: Input the length and cable type parameters of the test cable; Based on the cable impedance model and the internal resistance data of the switch matrix, the total impedance error of the test path is calculated. During the data acquisition phase, a reverse compensation value is simultaneously superimposed to output the corrected impedance result.

[0022] The backplane expansion interface of the switch matrix adopts a daisy-chain topology, supports multi-board cascading, and the maximum number of channels for a single collector is ≥40.

[0023] The host computer software platform includes: The test task configuration module supports batch import of test point sequences; The real-time data display module shows the impedance change trend in chart form; The fault diagnosis module locates problems such as poor cable contact or relay failure based on abnormal data.

[0024] An automated impedance testing method based on PCDU includes the following steps: Step 1: Initialize the configuration. Based on the test requirements and interface definition of the single machine, configure the relevant acquisition settings on the data acquisition unit, define the corresponding resistance range for each point, and configure the corresponding acquisition time on the host computer software platform according to the definition of whether the electrical connector point is inductive or capacitive impedance. Step 2: Input the parameters (length, wire type, etc.) and impedance criterion thresholds of the automated impedance test cable, and select the automatic or manual test mode through the host computer software; Step 3: Channel switching and data acquisition: The switch matrix selects the channel to be tested according to the instruction, and the data acquisition unit acquires the original impedance data according to the preset range. The path impedance error is calculated synchronously through the dynamic compensation and correction circuit and transmitted to the host computer for dynamic correction. Step 4: The corrected data is compared with the preset criteria on the host computer software platform. Qualified results are marked as "passed", and abnormal data generates an independent error file and triggers an alarm. Step 5: Impedance test data is stored in CSV or database format, and can be used to generate visualization charts or export test reports; Step 6: Summarize the impedance test results from different stages of the same PCDU development process or the impedance test results from multiple units of the same batch of satellite models, and judge whether the test data are consistent on the host computer software platform. The threshold criteria mentioned in step 3 are a two-point impedance difference ≤ 0.1Ω or a single-point impedance ≥ 10MΩ.

[0025] The channel scanning rate in step 2 is 40 channels / second, which supports skipping marked faulty channels.

[0026] When the DAQ970A data acquisition unit passes the 4-wire test, the Kelvin clip connection method is used to eliminate the influence of contact resistance.

[0027] This invention has been applied to impedance testing of PCDUs on GeeSAT-5 satellites, enabling the testing of 20 PCDUs and over 8000 channels per day with a false positive rate of less than 0.01%, saving 70% of labor time compared to traditional methods. The system is compatible with the high-precision impedance testing requirements of aerospace, military, and other fields, and has significant economic and engineering value.

[0028] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0029] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An automated impedance testing system for PCDU based on DAQ970, used for automatic impedance testing of PCDU, characterized in that: It includes a data acquisition unit, an expandable switch matrix, a dynamic compensation and correction circuit, and a host computer software platform, among which, The data acquisition unit is used to receive control signals sent by the host computer software platform, send control signals to the expandable switch matrix, acquire PCDU impedance data through the expandable switch matrix, and send it to the dynamic compensation and correction circuit. The expandable switch matrix is ​​used to receive control signals sent by the host computer software platform, configure parameters according to the control signals sent by the expandable switch matrix, connect the data acquisition unit and the PCDU, and transmit the PCDU impedance data to the data acquisition unit. The dynamic compensation and correction circuit is used to receive control signals sent by the host computer software platform, receive PCDU impedance data sent by the data acquisition unit, correct the PCDU impedance data according to the impedance error between the test cable and the expandable switch matrix, and send it to the host computer software platform. The host computer software platform is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit for interpretation and storage; it is also used to send control signals to the data acquisition unit, the expandable switch matrix and the dynamic compensation and correction circuit to realize test process control.

2. The PCDU automated impedance testing system based on DAQ970 according to claim 1, characterized in that: The data acquisition unit has a built-in ½-digit high-precision digital multimeter, which can perform 20-channel 2-wire high-impedance testing and 10-channel 4-wire low-impedance testing.

3. The PCDU automated impedance testing system based on DAQ970 according to claim 1, characterized in that: The expandable switch matrix adopts a plug-in relay structure, with each board supporting 40 channels of independent selection, and can meet the multi-interface requirements of the PCDU through backplane expansion.

4. The PCDU automated impedance testing system based on DAQ970 according to claim 3, characterized in that: The backplane expansion interface of the expandable switch matrix adopts a daisy-chain topology, supports multi-board cascading, and the maximum number of channels for a single collector is ≥40.

5. The PCDU automated impedance testing system based on DAQ970 according to claim 1, characterized in that: The host computer software platform is also used for setting impedance criteria and classifying and saving error information.

6. The PCDU automated impedance testing system based on DAQ970 according to claim 5, characterized in that: The host computer software platform includes a test task configuration module, a real-time data display module, and a fault diagnosis module, wherein... The test task configuration module is used to import test point sequences and control signals to the data acquisition unit, expandable switch matrix, and dynamic compensation and correction circuit. The real-time data display module is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit and display the impedance change trend. The fault diagnosis module is used to receive PCDU impedance data sent by the dynamic compensation and correction circuit, and locate problems such as poor cable contact or relay failure based on abnormal data.

7. The PCDU automated impedance testing system based on DAQ970 according to claim 1, characterized in that: The error correction method of the dynamic compensation correction circuit is as follows: input the length and line type parameters of the test cable; calculate the total impedance error of the test path based on the impedance model of the test cable and the internal resistance data of the switch matrix; superimpose the reverse compensation value on the PCDU impedance data and output the corrected impedance data.

8. An automated impedance testing method for PCDU based on DAQ970, characterized in that: The testing system according to any one of claims 1 to 7 specifically includes the following steps: (1) Initialization configuration: According to the test requirements and interface definition of PCDU single unit, configure the acquisition settings of data acquisition unit, define the corresponding resistance range of each point, and configure the corresponding acquisition time on the host computer software platform according to the definition of whether the electrical connector point is inductive or capacitive impedance. (2) Input the parameters and impedance criterion threshold of the automated impedance test cable, and set the automatic or manual test mode through the host computer software platform; (3) The expandable switch matrix selects the channel to be tested according to the instruction, and the data acquisition unit acquires PCDU impedance data according to the preset range. The path impedance error is calculated synchronously through the dynamic compensation and correction circuit and dynamically corrected. (4) Compare the corrected PCDU impedance data obtained in step (3) with the preset criteria on the host computer software platform. Qualified results are marked as "passed", and abnormal data generate an independent error file and trigger an alarm. (5) The corrected PCDU impedance data is stored in CSV or database format; (6) Change the test parameters and repeat steps (1) to (5) multiple times. Summarize the impedance test results of different stages in the development of the same PCDU or the impedance test results of multiple single units of the same batch of satellite models, and judge whether the test data is consistent on the host computer software platform.

9. The automated impedance testing method for PCDU based on DAQ970 according to claim 8, characterized in that: In step (2), the impedance criterion threshold is a two-point impedance difference ≤ 0.1Ω or a single-point impedance ≥ 10MΩ.

10. The automated impedance testing method for PCDU based on DAQ970 according to claim 8, characterized in that: In step (3), the channel scanning rate is 40 channels / second, and marked faulty channels are skipped.

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