An accelerometer test circuit system

Abstract

The present invention relates to the technical field of accelerometer testing, and particularly to an accelerometer testing circuit system, which includes a logic switch, an MCU processor, a conversion circuit, and a power consumption resistor. Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are all connected to the MCU processor, and the MCU processor controls the logic switch to select and connect the accelerometer to the conversion circuit or to select and connect the accelerometer to the power consumption resistor. The conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal, and the conversion circuit sends the frequency signal to the MCU processor. The test result has high reliability, can avoid damage caused by the untested accelerometer output terminal being open-circuited, and the test circuit system has a small volume and a light weight, which is convenient for turnover and movement.

Description

Technical Field

[0001] The present invention relates to the technical field of accelerometer testing, and in particular, to an accelerometer test circuit system. Background Art

[0002] Accelerometers play a crucial role in inertial measurement units. Accelerometers can provide continuous motion information of the carrier. In use, a decrease in the performance of the accelerometer will directly affect the accuracy of the system. One of the main factors affecting the performance of the accelerometer is insufficient stress release. If the accelerometer is put into production with "residual stress", during use, if the stress is released, it will cause changes in the main indicators of the accelerometer, resulting in a decrease in the accuracy of the system and even affecting the success or failure of the task. Based on this, it is very necessary to design an accurate, efficient and simple test device.

[0003] Chinese Patent CN117929789A discloses a quartz flexible accelerometer test device. This device uses a series model of a high-precision digital multimeter + sampling resistor to test the accelerometer. The high-precision multimeter makes the overall volume of the test device relatively large, causing difficulties in the turnover of the test device and being not suitable for use under multiple working conditions. The test result is also jointly determined by the high-precision multimeter and the test resistor. Therefore, any malfunction or accuracy reduction in any part of this device will lead to untrustworthy test results and cause invalid tests. Moreover, although this accelerometer test device can measure multiple accelerometers simultaneously, if the accelerometers are not tested after being powered on, the output terminals of the untested accelerometers will be suspended, which will damage these accelerometers themselves; or the tested accelerometers adopt a sequential power-on scheme, which will increase the total test time and cannot effectively improve the test efficiency. In addition, the accelerometer test device can only perform repetitive tests under simple working conditions and is not suitable for multiple working conditions and long-term power-on test conditions. Summary of the Invention

[0004] The present invention provides an accelerometer test circuit system, which simultaneously tests multiple accelerometers by means of measurement through a logic switch gating conversion circuit or power resistor consumption. When gated, the current flows into the conversion circuit for testing, and the test result has high reliability. When not gated, the current of the accelerometer flows into the power consumption resistor, avoiding damage to the accelerometer caused by the unloaded output terminal of the untested accelerometer. Moreover, the test circuit system is small in volume and light in weight, facilitating turnover and movement.

[0005] The technical solution adopted by the present invention to solve its technical problems is:

[0006] An accelerometer test circuit system that tests multiple accelerometers simultaneously. The accelerometer test circuit system includes a logic switch, an MCU processor, a conversion circuit, and a power consumption resistor. Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are all connected to the MCU processor. The MCU processor controls the logic switch to select the connection between the accelerometer and the conversion circuit or the connection between the accelerometer and the power consumption resistor. The conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal, and the conversion circuit sends the frequency signal to the MCU processor.

[0007] The MCU processor is connected to a host computer. The host computer sends control instructions to the MCU processor and receives the frequency signals of the accelerometers.

[0008] The accelerometer test circuit system further includes a power supply module. The power supply module provides working power for the accelerometers and each component in the accelerometer test circuit system.

[0009] The power supply module includes a 220V alternating current, an AC / DC power supply module, and a DC / DC power supply module connected in series.

[0010] The accelerometer test circuit system is packaged into a test device. Multiple accelerometers are assembled on a test fixture. The test device is connected to the test fixture through a test cable.

[0011] The MCU processor is provided with 16 control channels, and each control channel is connected to 3 logic switches.

[0012] The logic switch is an analog logic switch.

[0013] The conversion circuit includes an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit, and an output drive circuit. The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects the connection between the accelerometer and the conversion circuit, the integration circuit integrates the input current of the accelerometer. The threshold circuit is connected to the output end of the integration circuit. The control circuit is connected to the output end of the threshold circuit and is simultaneously connected to the output drive circuit and the clock circuit. The bridge switch circuit is simultaneously connected to the output end of the control circuit, the output end of the constant current source circuit, and the input end of the integration circuit. The constant current source temperature compensation circuit is connected to the constant current source circuit.

[0014] The resistance value of the power consumption resistor is 500Ω~3.5KΩ.

[0015] Compared with the prior art, the accelerometer test circuit system provided by the present invention has the following advantages: (1) The accelerometer test circuit system provided by the present invention simultaneously tests multiple accelerometers by means of measurement through a logic switch gating conversion circuit or power resistance consumption. The test results are not affected by the failure of the sampling resistor, and the reliability is high; when gating, the current flows into the conversion circuit for testing, and when not gated, the accelerometer current flows into the power consumption resistor, ensuring that the accelerometer can be powered on for a long time, avoiding the open circuit of the output end of the untested accelerometer, and thus causing damage to the accelerometer.

[0016] (2) The accelerometer test circuit system provided by the present invention measures the output current of the accelerometer through a conversion circuit to realize the test of the accelerometer; during long-term use, the scale factor (K1) and zero offset value (K0) of the accelerometer can be tested and calibrated by a simple method, and the accuracy of the accelerometer can be calibrated at any time to avoid invalid tests.

[0017] (3) The accelerometer test circuit system provided by the present invention has a high degree of automation and integration, has no operation difficulty, is easy to operate, can reduce the potential hidden dangers introduced to the accelerometer of the product due to improper operation, and the packaged test equipment is small in volume and light in weight, which is convenient for turnover and handling. Description of the Drawings

[0018] Figure 1 is the principle block diagram of the accelerometer test circuit system provided by the present invention;

[0019] Figure 2 is the gating control circuit diagram of the logic switch in the present invention;

[0020] Figure 3 is the principle block diagram of the conversion circuit in the present invention. Detailed Embodiments

[0021] The present invention will be further described below with reference to the drawings and embodiments.

[0022] The accelerometer test circuit system provided in this embodiment includes a logic switch, an MCU processor, a conversion circuit, a power consumption resistor, and a power supply module, and its principle block diagram is as Figure 1 shown. The power supply module provides working power for the accelerometer and each component in the accelerometer test circuit system. Specifically, the power supply module includes a 220V alternating current, an AC / DC power supply module, and a DC / DC power supply module connected in series. That is, the external power supply uses 220V alternating current, and internally, after an AC / DC power supply module and two DC / DC power supply modules are connected in series, power is supplied to each component (including the accelerometer).

[0023] In this embodiment, the logic switch, MCU processor, conversion circuit, power consumption resistor in the accelerometer test circuit system, and the AC / DC power module and DC / DC power module in the power supply module are encapsulated together into a test device. Multiple accelerometers are assembled on a test fixture. The test device is connected to the 220V AC power supply of the power supply module and the test fixture through test cables respectively. Both the test device and the test fixture are independent components, and the test device is powered by an external 220V AC power supply, which can ensure that the accelerometer can be tested under various working conditions and avoid damage to the accelerometer caused by improper operation of personnel. Moreover, the overall structure of the package is small in size and light in weight, which is convenient for handling and turnover and is suitable for testing under multiple working conditions.

[0024] Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are all connected to the MCU processor. The MCU processor controls the logic switch to select the connection between the accelerometer and the conversion circuit or the connection between the accelerometer and the power consumption resistor. The conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit (i.e., this accelerometer is in the test state), the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal. The conversion circuit sends the frequency signal to the MCU processor, and the MCU processor uses FPGA technology to calculate and process the frequency signal and outputs the test result data in real time. When the accelerometer is connected to the power consumption resistor (i.e., this accelerometer is not being tested), power consumption is carried out on the untested accelerometer to avoid damage to the accelerometer caused by the floating output end of the accelerometer. Specifically, the model of the MCU processor is GD32H7×. In this embodiment, the MCU processor is connected to a host computer (such as an industrial computer, a computer) and interacts in a response manner. The host computer sends a control instruction (sends an instruction) to the MCU processor and receives the frequency signal of the accelerometer (receives data).

[0025] The working process of the accelerometer test circuit system provided in this embodiment is as follows: After the test circuit system is powered on, the logic switch defaults to a high level. At this time, the outputs of all accelerometers flow into the power consumption resistor for power consumption. This measure can ensure that the test system is in a long-term standby state. When the host computer sends a start test instruction, the MCU processor controls to open the logic switch of the corresponding channel, connects the accelerometer of this channel to the conversion circuit, and makes the current of the accelerometer of this channel flow into the conversion circuit for data acquisition and processing, so as to realize the accurate measurement of the accelerometer current.

[0026] In this embodiment, the MCU processor is provided with 16 control channels, namely channels 1 to 16. Each control channel is connected to 3 logic switches. That is, the MCU processor in this embodiment can control 48 logic switches. Correspondingly, up to 48 accelerometers can be assembled on the test fixture, and 48 accelerometers can be tested at one time. The MCU processor controls one channel each time, that is, it controls 3 logic switches to select and switch the circuit and 3 accelerometers at a time. The conversion circuit tests 3 accelerometers simultaneously. The MCU processor receives instructions from the host computer, controls the FPGA to intelligently switch channels according to a predetermined process, automatically collects accelerometer signals of multiple channels, and sends the test results to the host computer in real time. It can realize fully automatic testing of multiple channels without manual operation. Through an instruction from a host computer, the intelligent test of the predetermined process can be completed, effectively improving the test efficiency and safety of the accelerometer.

[0027] Figure 2 It is the gating control circuit diagram of 3 logic switches (U11, U12, U13) on channel 1 (KIO-1). The IN end of each logic switch is connected to channel 1 (KIO-1) of the MCU processor. The VDD end of each logic switch is connected to the power supply module to obtain power. The D end (pin 5) of each logic switch is connected to the accelerometers (JDX-1, JDY-1, JDZ-1). The S1 end (pin 4) of each logic switch is connected to the power consumption resistors (R31, R35, R39). The S2 end (pin 6) of each logic switch is respectively connected to the conversion circuit. When the test system is powered on or no test command is received, the output current of the accelerometer flows from pin 5 into pin 4 and then out, thus avoiding the floating of the accelerometer output end. After receiving the test command, the output current of the accelerometer flows from pin 5 into pin 6 and then into the conversion circuit, so as to simultaneously test the accelerometers (JDX-1, JDY-1, JDZ-1). Specifically, the logic switch is an analog logic switch, which has the advantages of low insertion loss, high isolation, fast switching speed, good temperature stability, etc., and has an ESD protection circuit, and is reliable to use. In this embodiment, the resistance value of the power consumption resistor is 1KΩ.

[0028] In this embodiment, the conversion circuit includes an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit and an output drive circuit. Its principle block diagram is as Figure 3 shown. The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects and connects the accelerometer and the conversion circuit, the integration circuit integrates the input current (I 入)(Integrate. The threshold circuit is connected to the output terminal of the integrating circuit. The integrated signal is push-pull output to the threshold circuit. The control circuit is connected to the output terminal of the threshold circuit and is also connected to the output driving circuit and the clock circuit at the same time. The bridge switch circuit is connected to the output terminal of the control circuit, the output terminal of the constant current source circuit, and the input terminal of the integrating circuit at the same time. The constant current source temperature compensation circuit is connected to the constant current source circuit. The main functions of the threshold circuit and the control circuit are to judge the magnitude and polarity of the input current according to the magnitude of the output voltage of the integrating circuit within each clock cycle under the action of the reference 512kHz square wave clock signal, so as to control the on-off of the bridge switch circuit (selection control), that is, the control circuit controls the feedback of different constant current sources by detecting the change of the threshold voltage, and then realizes the control of the circuit; the constant current source circuit includes positive and negative constant current sources (I 恒 ), which are used as the electronic weights for current / frequency conversion and are the key components to ensure the conversion accuracy. The main function of the clock circuit is to provide a high-precision clock reference for the conversion circuit, which is the basis for the conversion circuit to improve the linearity by using equal-width control; the main function of the output driving circuit is to provide sufficient current driving ability for the output pulse signal (TTL pulse). This conversion circuit has the characteristics of high reliability and high conversion accuracy.

[0029] Measure the output current of the accelerometer through the conversion circuit to realize the test of the accelerometer; during long-term use, the scale factor (K1) and zero offset value (K0) of the accelerometer can be tested and calibrated by a simple method, which can be used to monitor the two indicators of the scale factor (K1) and zero offset value (K0) of the accelerometer for a long time. Specifically, the constant current source temperature compensation circuit includes a temperature compensated crystal oscillator. The temperature compensated crystal oscillator selects a temperature compensated high-precision crystal oscillator, whose frequency stability index is better than 2ppm in the temperature range of -55°C to +85°C. The scale factor (K1) non-linear correction technology and the temperature compensation method of the reference constant current source of the current / frequency conversion circuit are adopted to reduce the change of the scale factor within the working range.

Claims

1. An accelerometer test circuit system for testing multiple accelerometers simultaneously, characterized in that: The accelerometer test circuit system includes a logic switch, an MCU processor, a conversion circuit and a power consumption resistor. Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switch is connected to the MCU processor. The MCU processor controls the logic switch to select the accelerometer and the conversion circuit or the accelerometer and the power consumption resistor; the conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal. The conversion circuit sends the frequency signal to the MCU processor. The conversion circuit includes The invention comprises an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit and an output drive circuit. The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects the accelerometer and the conversion circuit, the integration circuit integrates the input current of the accelerometer. The threshold circuit is connected to the output end of the integration circuit. The control circuit is connected to the output end of the threshold circuit and is also connected to the output drive circuit and the clock circuit. The bridge switch circuit is simultaneously connected to the output end of the control circuit, the output end of the constant current source circuit and the input end of the integration circuit. The constant current source temperature compensation circuit is connected to the constant current source circuit.

2. The accelerometer test circuit system according to claim 1, characterized in that: The MCU processor is connected to a host computer, and the host computer sends a control instruction to the MCU processor and receives a frequency signal from the accelerometer.

3. The accelerometer test circuit system according to claim 1, characterized in that: The accelerometer test circuit system also includes a power supply module, which provides working power to the accelerometer and various components in the accelerometer test circuit system.

4. The accelerometer test circuit system according to claim 3, characterized in that: The power supply module includes a 220V alternating current, an AC / DC power supply module and a DC / DC power supply module connected in series.

5. The accelerometer test circuit system according to claim 1, characterized in that: The accelerometer test circuit system is packaged into a test device, a plurality of accelerometers are assembled on a test fixture, and the test device is connected to the test fixture via a test cable.

6. The accelerometer test circuit system according to claim 1, characterized in that: The MCU processor is provided with 16 control channels, and each control channel is connected to 3 logic switches.

7. The accelerometer test circuit system according to claim 1, characterized in that: The logic switch is an analog logic switch.

8. The accelerometer test circuit system according to claim 1, characterized in that: The resistance of the power consumption resistor is 500Ω~3.5KΩ.

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