Automatic test equipment of array type magnetometer electric control system

Abstract

The invention discloses automatic test equipment of an array type magnetometer electric control system. The automatic test equipment comprises an upper computer and an analog probe connected with the upper computer, the simulation probe comprises a current simulation module which simulates the photocurrent of a magnetometer to be output to a detection object according to an instruction of a main control module; the signal sampling module is used for sampling the three-axis magnetic compensation signal and the heating signal or the signal source signal and transmitting the three-axis magnetic compensation signal and the heating signal or the signal source signal to the main control module; the amplitude detection module is used for converting the heating signal into a direct-current signal in linear relation with a signal peak value and inputting the direct-current signal into the signal sampling module; the signal shaping module converts the heating signal into a square wave signal and inputs the square wave signal into the master control module for frequency detection; and the switching multiplexing module is used for selecting and switching signal channels according to an instruction of the main control module. According to the invention, the manual wiring and switching process is greatly simplified, the automation degree of the system is improved, and the detection efficiency and consistency of the array type magnetometer electric control system can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetometer testing, in particular to an automatic test equipment of an array magnetometer electric control system. BACKGROUND

[0002] The array magnetometer electric control system and the magnetometer probe array together constitute an array magnetometer system. The magnetometer probe based on the spin exchange relaxation free rate principle can realize high-sensitivity measurement of extremely weak magnetic signals, and the average sensitivity of magnetic field acquisition can reach 20fT / Hz 1 / 2 . The array structure constructed by multiple probes can realize high spatial resolution magnetic source imaging function. To ensure the normal work of the magnetometer probe, it needs to run in a controlled magnetic environment. The array magnetometer electric control system first controls the internal chamber of the probe with high precision, and realizes three-axis magnetic compensation to establish an approximate zero magnetic field working environment. Under the premise of meeting the external environmental conditions, the system detects the photoelectric current signal output by the magnetometer probe, combines the internal signal processing and solving algorithm, and finally obtains the target magnetic field strength value. For any electronic equipment facing mass production delivery, it usually faces the needs of automatic detection and rapid verification. However, for the array magnetometer electric control system, there is still no mature and special automatic detection solution in the industry. The existing detection means still mainly relies on traditional general test instruments such as oscilloscopes and signal generators, and each channel is verified one by one by manual method. Not only the wiring is complicated and the configuration is complex, but also the professional dependence on the operator is strong, the detection efficiency is low, and it is difficult to meet the testing needs of large quantities, high consistency and rapid delivery.

[0003] A kind of array magnetometer calibration device and method based on magnetic dipole model disclosed in Chinese patent document, its publication number is CN117110965A, and the publication date is November 24, 2023, including spherical magnetic source model and calibration base, spherical surface of spherical magnetic source model is distributed with coil winding cylinder array, each coil winding cylinder is protruded on spherical surface, the center of right side surface of spherical surface extends out the transverse circular shaft connected with disc base, calibration base has the square cavity with upper opening, SERF atomic magnetometer slot array is opened in the left side wall of square cavity, coil slot array is opened in the upper half of front side wall and the upper half of rear side wall of square cavity, the right side of square cavity is semicircular groove body, calibration base groove is formed between the right end face of semicircular groove body and the right end plate of the calibration base, the calibration base groove is matched with the disc base, the semicircular groove of semicircular groove body is matched with the transverse circular shaft, and the spherical surface is located in the square cavity. The technology is a device and method for calibrating array magnetometer. For array magnetometer electric control system, there is still a lack of automatic detection equipment, and it needs to rely on traditional general test instruments to test each channel one by one manually, which is complicated and inefficient. SUMMARY

[0004] The present application is to overcome the prior art mainly relies on the traditional general test instrument through artificial way to array magnetometer electric control system each channel one by one function verification, not only wiring is complicated, configuration is complex, and the professional dependence of the operator is strong, the detection efficiency is low, provides a kind of array magnetometer electric control system's automated test equipment.

[0005] In order to achieve the above object, the present application adopts the following technical scheme: An automated test equipment of array magnetometer electric control system, comprising a host computer and analog probe connected thereto;The analog probe comprises: Current simulation module, according to the instruction of main control module, simulates the photocurrent output of magnetometer to the detection object; Signal sampling module, sampling three-axis magnetic compensation signal and heating signal or signal source signal, and transmitting to main control module; Amplitude detection module, heating signal is converted into a linear relationship with signal peak DC signal input signal sampling module; Signal shaping module, heating signal is converted into square wave signal input main control module for frequency detection; Switching multiplexing module, according to the instruction of main control module, the selection switching of signal channel is carried out.

[0006] As preferred, the automated test equipment takes array magnetometer electric control system as detection object, the host computer is respectively connected with analog probe and detection object communication, carries out analog probe control and detection object control; Array magnetometer electric control system is connected with analog probe through adapter wire, and a corresponding number of analog probes are connected according to the number of channels of the detection object.

[0007] As preferred, the current simulation module comprises first simulation unit and second simulation unit with same circuit structure; The first simulation unit comprises a digital-to-analog conversion chip with several independent output channels, each independent output channel is connected with a constant current source circuit, and the simulated magnetometer photocurrent is output from the output end of the constant current source circuit.

[0008] As preferred, in the constant current source circuit, the independent output channel is connected with one end of the second resistor, one end of the first capacitor and the positive input end of the second operational amplifier through the first resistor;The other end of the first capacitor is grounded, and the other end of the second resistor is connected with the output end and the inverting input end of the first operational amplifier;The inverting input end of the second operational amplifier is grounded through the third resistor, and is connected with the output end of the second operational amplifier through the parallel resistor-capacitor;The output end of the second operational amplifier is connected with the positive input end of the first operational amplifier through the fourth resistor, as the output end of the constant current source circuit.

[0009] Preferably, the signal sampling module comprises an analog-digital conversion chip comprising at least four sampling channels; The first to third sampling channels in the analog-digital conversion chip respectively collect three-axis magnetic compensation signals; the fourth sampling channel detects the amplitude of a heating signal or a signal source signal, and switches two detection signals through a relay.

[0010] Preferably, the signal sampling module further comprises a switching circuit and an amplification circuit corresponding to the three-axis magnetic compensation signals; For the magnetic compensation signal of any axis, the gain of the analog probe circuit is automatically adjusted according to the size of the magnetic compensation signal output by the array magnetometer electric control system, and the magnetic compensation signal is amplified or attenuated before being input into the signal sampling module for sampling.

[0011] Preferably, the amplitude detection module comprises a signal conditioning circuit, a rectifier circuit and a filter circuit connected in sequence; The signal conditioning circuit amplifies or attenuates the heating signal through the combination of the third operational amplifier and different feedback resistors; The rectifier circuit unidirectionally rectifies the conditioned signal through a half-wave rectifier, and then inversely processes the signal through a fourth operational amplifier to output to the filter circuit; The filter circuit is an RC low-pass filter circuit, which outputs a direct current signal in linear relationship with the peak value of the heating signal.

[0012] Preferably, the signal shaping module comprises a comparator; after the heating signal is coupled through a second capacitor, it is clamped to a safe level through a limiting diode, and the clamped signal is input into the inverting input terminal of the comparator through a fifth resistor; the non-inverting input terminal of the comparator inputs a reference level; the output terminal of the comparator outputs a square wave signal to the main control module after current limiting through a sixth resistor.

[0013] Preferably, in the switching and multiplexing module, the instructions sent from the main control module are output through a shift register, and then drive and control the on-off of the relay array through a Darlington tube to select and switch the signal channel; The relay array comprises a first relay array for switching between analog current output and noise test, and a second relay array for selecting one of several channels of the detection object for detection; The first relay array comprises a plurality of first sub-arrays with the same structure, and each first sub-array corresponds to a channel of a detection object.

[0014] As preferred, in the first sub-array, the analog magnetometer photocurrent inputs the moving contact of the fifth relay, the normally closed contact of the fifth relay is connected to the ground through the seventh resistor, the normally open contact of the fifth relay is connected to the normally open contact of the first relay, the moving contact of the first relay outputs the analog magnetometer photocurrent to the detected object, the normally closed contact of the first relay is connected to the normally open contact of the second to fourth relays respectively, and the moving contact of the second to fourth relays respectively inputs the three-axis magnetic compensation signals of the detected object and outputs by the corresponding normally closed contact.

[0015] The application has the following beneficial effects: by integrating various functional modules and programmable control logic, a set of integrated automatic test equipment with high precision, high efficiency and strong compatibility is constructed, which can significantly improve the detection efficiency and consistency of the array magnetometer electric control system in the production test, research and development verification and fault diagnosis process; one or two analog probes can be selectively accessed according to the channel number of the detected object to cover all channel detection, improving the flexibility of the electric control system detection; a heating signal shaping module is designed to realize accurate detection of the heating signal frequency, ensure the heating frequency consistency of the magnetometer array, and improve the magnetic field detection precision; a switching multiplexing module is designed to dynamically switch and collect different types of signals, greatly simplifying the manual wiring and switching process, and improving the system automation level. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is the module schematic diagram of the automatic test equipment of the array magnetometer electric control system in the application.

[0017] Figure 2 is the circuit diagram of the main control module in the application.

[0018] Figure 3 is the circuit diagram of the communication connection unit in the main control module in the application.

[0019] Figure 4 is the circuit diagram of the first analog unit in the current analog module in the application.

[0020] Figure 5 is the circuit diagram of the second analog unit in the current analog module in the application.

[0021] Figure 6 is the circuit diagram of the signal acquisition module in the application.

[0022] Figure 7 is the circuit diagram of the signal switching and amplification in the signal acquisition module in the application.

[0023] Figure 8 is the circuit diagram of the amplitude detection module and the signal shaping module in the application.

[0024] Figure 9 is the circuit diagram of the switching multiplexing module in the application.

[0025] Figure 10 is the circuit diagram of the first relay array, the second relay array in the switching multiplexing module in the application.

[0026] Figure 11 is the circuit diagram of the remaining relay array in the switching multiplexing module in the application.

[0027] Figure 12 is the schematic diagram of the switching line of the analog probe and the array magnetometer electric control system in the application.

[0028] Figure 13 is the overall detection flow chart of the automatic test equipment in the application. DETAILED DESCRIPTION

[0029] The application will be further described below in combination with the drawings and the specific embodiments.

[0030] As shown in Figure 1 , an automatic test equipment of an array magnetometer electric control system, comprising an array magnetometer electric control system as a detection object and an analog probe connected therewith; the analog probe comprises: a current simulation module for simulating the photoelectric current output of the magnetometer to the detection object according to the instruction of a master control module; a signal sampling module for sampling the three-axis magnetic compensation signal and the heating signal or the signal source signal and transmitting to the master control module; an amplitude detection module for converting the heating signal into a direct current signal input signal sampling module in linear relation with the signal peak value; a signal shaping module for converting the heating signal into a square wave signal inputting the master control module for frequency detection; a switching multiplexing module for selecting and switching the signal channel according to the instruction of the master control module.

[0031] It should be noted that the application integrates multiple functional modules to build a set of integrated automatic test equipment with high precision, high efficiency and strong compatibility, which can significantly improve the detection efficiency and consistency of the array magnetometer electric control system in the production test, research and development verification and fault diagnosis process; one or two analog probes can be selectively accessed according to the channel number of the detection object to cover all channel detection, improving the flexibility of electric control system detection; the heating signal shaping module is designed to realize accurate detection of the heating signal frequency, ensure the heating frequency consistency of the magnetometer array, and improve the magnetic field detection precision; the switching and multiplexing module is designed to dynamically switch and collect different types of signals, greatly simplify the manual wiring and switching process, and improve the system automation. The array magnetometer electric control system detection by the automatic test equipment instead of manual operation can avoid complicated wiring and operation, thereby improving the test efficiency, and avoiding manual test misoperation, thereby improving the reliability.

[0032] It is worth noting that the array magnetometer system mainly includes an array magnetometer electric control system and a magnetometer probe array. During normal use, the array magnetometer electric control system detects the current signal output by the magnetometer probe, and calculates the magnetic field strength through internal algorithms. However, before formal delivery, the current detection accuracy of the array magnetometer electric control system needs to be verified, so the electric control system will be connected to the automatic test equipment, which will output a known high-precision current to the electric control system. By comparing the detected value and the actual output value of the electric control system, it can be determined whether the detection accuracy meets the requirements, and the electric control system is detected (for example, the analog probe will output multiple fixed current values within the current detection range of the array magnetometer electric control system for the array magnetometer electric control system to detect. If the error exceeds ±5%, it is determined to be unqualified; when the output current value is 0, the judgment standard is-2uA-2uA, and the error exceeding the corresponding range is determined to be unqualified). In addition, the magnetic probe needs to work in a specific temperature environment, generally 150℃, in order to meet this condition, the probe is provided with a heating coil, and the array magnetometer electric control system outputs a fixed 400KHz sin waveform to the coil. In order to accurately control the temperature, PT1000 is used as a temperature feedback unit.

[0033] Specifically, the analog probe mainly comprises a main control module, a current analog module, a signal sampling module, an amplitude detection module, a signal shaping module and a switching multiplexing module. The current analog module is a 16-bit four-channel digital-to-analog converter, which is used to generate an analog PD current signal, and the analog PD current signal is output to an array magnetometer electric control system via a double operational amplifier constant current source composed of OPA2192 for current detection verification. The signal sampling module is a 16-bit analog-to-digital converter, which is used to detect three-axis magnetic compensation signals, heating signals and signal source signals output by the array magnetometer electric control system. The magnetic compensation signal measurement can simultaneously measure the signals of XYZ three axes according to the needs, and the signal source signal measurement detects only one way at the same time.

[0034] For the data acquisition and processing of the three-axis magnetic compensation signal, the actual detection result is obtained by comparing the ADC detection value collected by the signal sampling module with the circuit gain; and the signal frequency of any axis is calculated separately, the actual voltage value of the axis is the voltage value of the axis minus the voltage bias of the axis, the zero crossing point of the actual voltage value is detected and the zero crossing time is recorded (the previous voltage value of the axis is greater than 0 and the current voltage value of the axis is less than 0, which can be judged as the zero crossing point), the time between two adjacent zero points is a period, and the reciprocal of the period is the frequency; the three-axis voltage signal and the frequency of the axis are uploaded to the host computer for display. The host computer converts the three-axis voltage signal into a current value and compares it with a preset current range, and if it exceeds the preset current range, it is determined as unqualified.

[0035] For the setting of the circuit gain, specifically, when the voltage amplitude is below 4mVrms, 3-stage amplification (the amplification ratio can be 441 times) is started; when the voltage amplitude is in [4mVrms, 100mVrms], 2-stage amplification (the amplification ratio can be 21 times) is started, and when the voltage amplitude is greater than 100mVrms, 1-stage amplification (the amplification ratio can be 1 times) is started; the setting basis is that the smaller the signal gain, the greater the signal gain, so that the small signal can be amplified as much as possible to improve the signal detection accuracy; the processed signal cannot exceed the sampling range of the signal sampling module.

[0036] The processing method of the signal source signal is different from that of the three-axis magnetic compensation signal in that the voltage signal is fixed at a certain preset voltage bias (100mV voltage bias can be selected) when the frequency is detected, so as to ensure the zero crossing point of the signal source signal. Specifically, the actual detection result is obtained by collecting the signal sampling module; the frequency of the signal source signal is calculated, the signal voltage is the signal voltage minus the preset voltage bias, the zero crossing point of the signal voltage is detected and the zero crossing time is recorded (the previous signal voltage value is greater than 0 and the current signal voltage value is less than 0, which can be judged as the zero crossing point), the time between two adjacent zero points is a period, and the reciprocal of the period is the frequency; the signal source voltage signal and the frequency are uploaded to the host computer for display. The host computer compares the signal source voltage signal with a preset voltage range, and if it exceeds the preset voltage range, it is determined as unqualified.

[0037] The amplitude detection circuit is used for converting the heating signal with a fixed frequency of 400 KHz into a direct current signal, the output of which is in linear relationship with the peak value of the original heating signal, so that the amplitude of the heating signal can be calculated through the ADC sampling result of the signal sampling module. The data processing process of the heating signal includes: obtaining the frequency of the heating signal, and converting the heating signal with the frequency into a direct current signal in linear relationship with the peak value of the heating signal; testing equipment calibration; heating signal peak value calculation.

[0038] The testing equipment calibration: for the heating signal, since the heating signal waveform output by the array type magnetometer electric control system is truncated, the linear error exists between the amplitude detection value and the actual amplitude value, so it is necessary to calibrate the amplitude detection value of the heating signal. The calibration steps are: using an oscilloscope to obtain the actual amplitude value of the heating signal waveform; using an analog probe to detect the heating signal to obtain the amplitude detection value; using the least square method to fit the [amplitude detection value, actual amplitude value] data set to obtain the k, b coefficients; obtaining the calibration relationship between the actual amplitude value and the amplitude detection value, that is, the actual amplitude value=k*amplitude detection value+b, and completing the calibration.

[0039] The heating signal peak value calculation: first, the voltage value of the heating signal is sampled from the signal sampling module, and then the voltage value is divided by the circuit gain and multiplied by 2 as the amplitude detection value; the calibration relationship is used to calibrate the amplitude detection value to obtain the actual amplitude value; the actual amplitude value and the frequency of the heating signal are uploaded to the host computer for display. The host computer compares the actual amplitude value with the preset amplitude range, and if it exceeds the preset amplitude range, it is determined as unqualified.

[0040] At the same time, in order to realize the accurate detection of the frequency of the heating signal, the original heating signal is converted into a square wave signal with consistent frequency through the signal shaping module, and the signal is input into the timer unit of the host control module. The host control module calculates the frequency of the heating signal by counting the number of square wave pulses in a set time window through high-precision frequency counting. Specifically, TIM1 is set to external trigger mode, and the count value is increased by 1 every time the rising edge of the heating signal is received; TIM2 is set to record the TIM1 count value every fixed interval (such as 50 ms); the frequency is the difference between the TIM1 count value and the last TIM1 count value divided by the fixed interval.

[0041] The switching multiplexing module, comprised of a GN595T shift register and relay array, provides flexible switching between signal channels and simulates a PT1000 resistor output to support calibration and verification of temperature measurement functions. Specifically, the array magnetometer system's temperature measurement module exhibits linearity errors and requires pre-delivery calibration. This calibration method involves using an analog probe to output a known resistor to the magnetometer for measurement. This generates a [theoretical temperature, measured temperature] data set. The data set is then fitted using the least squares method to obtain the corresponding coefficients k and b, resulting in a final measured temperature of k*initial measured temperature + b, achieving temperature calibration.

[0042] Furthermore, the automated test equipment also includes a host computer, which communicates with the analog probes and the test object, respectively, to control the analog probes and the test object. The array magnetometer's electronic control system is connected to the analog probes via adapter cables, with a corresponding number of analog probes connected based on the number of test object channels. The entire device is powered by a power supply module, which connects to the corresponding power supply based on the power requirements of each module within the device. Because the specific power supply circuit is a conventional technology, it will not be described in detail.

[0043] It should be noted that the device of the present invention consists of a host computer and an analog probe, and uses an array magnetometer electronic control system (which can be divided into a four-channel single-light acquisition board and a miniaturized main control unit based on the number of channels) as the detection target. High-speed communication between the host computer and the analog probe is achieved via a USB 2.0 interface, and data exchange between the host computer and the array magnetometer electronic control system is achieved via a network cable. The analog probe is powered by a DC12V / 1A power adapter, ensuring excellent portability and power adaptability.

[0044] It's worth noting that the host computer integrates analog probe control, acquisition board control, and miniaturized main control (i.e., control of the array magnetometer's electronic control system). It can simultaneously manage up to two analog probes, enabling up to eight channels of photocurrent analog output, resistance analog output, three-axis magnetic compensation signal detection, heating signal detection, source signal detection, and input and output noise testing. When testing a four-channel single-light acquisition board, only one analog probe is required to complete the entire test process. However, for functional verification of the miniaturized main control, two analog probes must be connected simultaneously to cover all channels.

[0045] As a specific example, Figure 2The circuit diagram of the master module in the application is shown. The MCU of the master module is STM32F407VET6, which is based on high-performance Arm Cortex-M4, 32-bit RISC core, and the working frequency is as high as 168 MHz. The Cortex-M4 core has a floating-point unit (FPU) single-precision, supporting all ARM single-precision data processing instructions and data types. It also implements a complete set of DSP instructions and a memory protection unit (MPU), improving the security of the application program. The master module is connected with the current simulation module, the signal sampling module, the signal shaping module and the switching multiplexing module respectively.

[0046] Specifically, the master module and the current simulation module are connected through seven ports of 8734_CS, 8734_SCK, 8734_SDI, 8734_SDO, 8734_LDAC, 8734_CS2 and 8734_LDAC2 for information interaction. The master module connects the first analog unit in the current simulation module through five ports of 8734_CS, 8734_SCK, 8734_SDI, 8734_SDO and 8734_LDAC, and connects the second analog unit in the current simulation module through five ports of 8734_CS2, 8734_SCK, 8734_SDI, 8734_SDO and 8734_LDAC2.

[0047] The master module and the signal sampling module are connected through seven ports of 2357_PD, 2357_BUSY, 2357_CNV, 2357_CS, 2357_SCK, 2357_SDI and 2357_SDO0 for information interaction. At the same time, the master module connects the relay control circuit of the amplitude detection module through the HBP end and the HDX end to control the on-off of the corresponding relay, and connects the relay control circuit of the switching circuit in the signal sampling module through the XBP, YBP, ZBP and HOC ends to control the on-off of the corresponding relay. The master module is connected with the signal shaping module through the HEATF end to receive information from the signal shaping module.

[0048] The master module and the switching multiplexing module are connected through five ports of 595_SER, 595_G, 595_RCK, 595_SCK and 595_SCLR to output corresponding information to the displacement register in the switching multiplexing module for relay array on-off control, and then select and switch the signal channel.

[0049] As Figure 3As shown, the master module further comprises a communication connection unit connected thereto, the communication connection unit is divided into an Ethernet unit and a USB unit, wherein the Ethernet unit selects YT8512C as an Ethernet PHY chip, and realizes all physical layer functions required for transmitting and receiving data through an RJ45 interface; at the same time, the Ethernet unit is connected to the MCU in the master module through a standard RMII interface. As for the USB unit, a TYPE, 16P, QTGM027 type USB interface is selected, which is connected to the MCU in the master module through USB_P and USB_N terminals.

[0050] As a specific embodiment, the current simulation module comprises a first simulation unit and a second simulation unit which have the same circuit structure; as Figure 4 As shown in the circuit diagram of the first simulation unit, as Figure 5 As shown in the circuit diagram of the second simulation unit.

[0051] The first simulation unit comprises a digital-to-analog conversion chip with a plurality of independent output channels VO, each independent output channel VO is connected to a constant current source circuit, and outputs a simulated magnetometer photocurrent from the output end of the constant current source circuit.

[0052] It should be noted that the present application uses a DAC digital-to-analog conversion chip plus a constant current source circuit to simulate the output of the magnetometer photocurrent, uses two pieces of digital-to-analog conversion chip DAC8734 to simulate the photocurrent signal output of PD1 and PD2 respectively, and a single DAC8734 has four independent output channels VO0-VO3. The communication mode between DAC8734 and MCU is SPI, and the constant current source circuit uses a double operational amplifier form composed of OPA2192, which has good output accuracy and noise performance, and the noise performance can be as low as 100nA or less. The voltage is converted to current through the circuit and output through the PDXXOUT terminal. The photocurrent model of PD1 and PD2 each has four channels, so two pieces of DAC8734 are used, the first piece of digital-to-analog conversion chip is applied to the first simulation unit to specially output the PD1 current signal, and the second piece of digital-to-analog conversion chip is applied to the second simulation unit to specially output the PD2 current signal.

[0053] Further, in the constant current source circuit, the independent output channels are connected to one end of the second resistor, one end of the first capacitor and the non-inverting input end of the second operational amplifier through the first resistor respectively; the other end of the first capacitor is grounded, and the other end of the second resistor is connected to the output end and the inverting input end of the first operational amplifier respectively; the inverting input end of the second operational amplifier is grounded through the third resistor, and is connected to the output end of the second operational amplifier through the parallel resistor-capacitor; the output end of the second operational amplifier is connected to the non-inverting input end of the first operational amplifier through the fourth resistor, as the output end of the constant current source circuit.

[0054] Specifically, for the circuit of the first analog unit, it includes a digital-to-analog conversion chip U26, the digital-to-analog conversion chip U26 is connected to the MCU of the host module through five ports 8734_CS, 8734_SCK, 8734_SDI, 8734_SDO and 8734_LDAC, and outputs signals from four independent output channels 8734_VO0 to 8734_VO3 to respective constant current source circuits based on current simulation instructions from the host module. The signal output by 8734_VO0 is output as an analog current PD11OUT after passing through the constant current source circuit, the signal output by 8734_VO1 is output as an analog current PD12OUT after passing through the constant current source circuit, the signal output by 8734_VO2 is output as an analog current PD13OUT after passing through the constant current source circuit, and the signal output by 8734_VO3 is output as an analog current PD14OUT after passing through the constant current source circuit.

[0055] For the four constant current source circuits in the first analog unit, because their circuit structures are the same, the constant current source circuit connected to the 8734_VO0 channel output is taken as an example for description.

[0056] The 8734_VO0 channel is connected to one end of a resistor R138, one end of a capacitor C193 and the non-inverting input terminal of an operational amplifier U28B through resistors R137, the other end of the capacitor C193 is grounded, and the other end of the resistor R138 is connected to the output terminal and the inverting input terminal of the operational amplifier U28A; the operational amplifier U28A is connected to the bias voltage of AN15V. The inverting input terminal of the operational amplifier U28B is grounded through a resistor R131, and is connected to the output terminal of the operational amplifier U28B through a resistor R132 and a capacitor C191 in parallel; the output terminal of the operational amplifier U28B is connected to the non-inverting input terminal of the operational amplifier U28A through a resistor R134 as the output terminal PD11OUT of the constant current source circuit, and the terminal is grounded through a resistor R140.

[0057] For the circuit of the second analog unit, it includes a digital-to-analog conversion chip U61, the digital-to-analog conversion chip U61 is connected to the MCU of the host module through five ports 8734_CS2, 8734_SCK, 8734_SDI, 8734_SDO and 8734_LDAC2, and outputs signals from four independent output channels 8734_VO0A to 8734_VO3A to respective constant current source circuits based on current simulation instructions from the host module. The signal output by 8734_VO0A is output as an analog current PD21OUT after passing through the constant current source circuit, the signal output by 8734_VO1A is output as an analog current PD22OUT after passing through the constant current source circuit, the signal output by 8734_VO2A is output as an analog current PD23OUT after passing through the constant current source circuit, and the signal output by 8734_VO3A is output as an analog current PD24OUT after passing through the constant current source circuit.

[0058] For the four constant current source circuits in the second analog unit, because their circuit structures are the same, the constant current source circuit connected with the 8734_VO0A channel output is taken as an example for description.

[0059] The 8734_VO0A channel is connected with one end of the resistor R185, one end of the capacitor C268 and the non-inverting input terminal of the operational amplifier U58B through the resistor R184, the other end of the capacitor C268 is grounded, and the other end of the resistor R185 is connected with the output terminal and the inverting input terminal of the operational amplifier U58A respectively; the operational amplifier U58A is connected with the bias voltage of the AN15V. The inverting input terminal of the operational amplifier U58B is grounded through the resistor R175, and is connected with the output terminal of the operational amplifier U58B through the parallel resistor R176 and the capacitor C266; the output terminal of the operational amplifier U58B is connected with the non-inverting input terminal of the operational amplifier U58A through the resistor R181 as the output terminal PD21OUT of the constant current source circuit, and the terminal is grounded through the resistor R229 at the same time.

[0060] It should be noted that the analog currents PD1 and PD2 in the current analog module each have four output paths, and eight current output channels PD11OUT, PD12OUT, PD13OUT, PD14OUT and PD21OUT, PD22OUT, PD23OUT, PD24OUT are formed by two DAC8734 and eight OPA2192. The eight analog current outputs are connected to the first relay array of the switching and multiplexing module, and the switching of the analog current outputs and the noise test is based on the on-off control of the relay array.

[0061] As a specific embodiment, the signal sampling module includes at least four sampling channels of an analog-digital conversion chip; The first to third sampling channels in the analog-digital conversion chip respectively collect three-axis magnetic compensation signals; the fourth sampling channel detects the heating signal amplitude or the signal source signal, and switches two detection signals through a relay.

[0062] It should be noted that, as shown in Figure 6 LTC2357 in the signal sampling module is a 4-channel ADC chip with 16-bit resolution, wherein channels 1-3 are used for three-axis magnetic compensation signal collection, and channel 4 is used for heating signal amplitude detection or signal source signal detection, and two signals are switched through a relay. The communication between the LTC2357 and the MCU of the main control module uses SPI, and in order to prevent the input signal from being too large to burn the ADC, diodes D16-D23 are added to the circuit for protection.

[0063] Specifically, the circuit of the signal sampling module includes an analog-to-digital conversion chip U30. The analog-to-digital conversion chip U30 is connected to the MCU of the main control module through seven ports, namely 2357_PD, 2357_BUSY, 2357_CNV, 2357_CS, 2357_SCK, 2357_SDI and 2357_SDO0, and inputs the collected three-axis magnetic compensation signal and heating signal or signal source signal into the main control module.

[0064] The X-axis magnetic compensation signal is sampled in the first sampling channel of the analog-to-digital conversion chip U30. The positive terminal of the first sampling channel is connected to one end of the capacitor C240 ​​and one end of the resistor R219 respectively; the negative terminal of the first sampling channel is connected to the other end of the capacitor C240 ​​and grounded; the other end of the resistor R219 is connected to the input end X of the X-axis magnetic compensation signal; one end of the resistor R219 is connected to the AP5V power supply through the diode D16, and is connected to the AN5V power supply through the diode D17.

[0065] The circuit structure from the second sampling channel to the fourth sampling channel of the analog-to-digital conversion chip U30 is the same as that of the first sampling channel. The second sampling channel is connected to the input terminal Y of the Y-axis magnetic compensation signal, the third sampling channel is connected to the input terminal Z of the Z-axis magnetic compensation signal, and the fourth sampling channel is connected to the input terminal H / C of the heating signal or the signal source signal.

[0066] Furthermore, the signal sampling module further includes a switching circuit and an amplifying circuit corresponding to the three-axis magnetic compensation signal; and a switching circuit corresponding to the heating signal or the signal source signal; For the magnetic compensation signal of any axis, the analog probe circuit gain is automatically adjusted according to the size of the magnetic compensation signal output by the array magnetometer electronic control system, and the magnetic compensation signal is amplified or attenuated before being input into the signal sampling module for sampling.

[0067] Specifically, such as Figure 7 The device shown includes a switching circuit, a corresponding relay array, and an amplifying circuit for a three-axis magnetic compensation signal.

[0068] The setting of the switching circuit in the present invention realizes the specific switching function by controlling the on-off of the relays in the circuit. In this embodiment, there are six relays from K31 to K36. In order to reduce the number of relays used in the switching circuit, a double-pole double-throw relay of model HFD4 / 5SR is used to connect to the switching circuit. The control circuits of relays K34 and K36 of the amplitude detection module are connected through the HBP terminal and HDX terminal to control the on-off of the corresponding relays; the control circuits of relays K31, K32, K33 and K35 of the switching circuit in the signal sampling module are connected through the XBP, YBP, ZBP and HOC terminals.

[0069] The six relay control circuits in the embodiment are of the same structure, and thus only the relay control circuit connected with the XBP terminal is taken as an example for description. Figure 7 The XBP terminal of the main control module MCU is connected with the gate of the MOS tube Q13, and the MOS tube can be of the model 2N7002LT3G. The gate of the MOS tube Q13 is connected with the source of the MOS tube Q13 through the resistor R159 and grounded. The drain of the MOS tube Q13 is connected with one end of the coil of the relay K31 and the anode of the diode D24, respectively. The other end of the coil of the relay K31 is connected with the cathode of the diode D24 and the P5V_1 power supply. The coil of the relay K31 is also connected with the resistor R145 and the series branch of the light emitting diode D26.

[0070] For the remaining relay control circuits, the YBP terminal controls the on-off of the relay K32, the ZBP terminal controls the on-off of the relay K33, the HBP terminal controls the on-off of the relay K34, the HOC terminal controls the on-off of the relay K35, and the HDX terminal controls the on-off of the relay K36.

[0071] For the switching circuit, it includes the switching circuit of the heating signal and the signal source signal, and the switching circuit of the three-axis magnetic compensation signal. For the switching circuit of the heating signal and the signal source signal, the relay K35 is used for switching control. The first movable contact of the relay K35 is connected with the H / C terminal of the fourth sampling channel, the first normally closed contact is connected with the heating signal amplitude HA terminal, and the first normally open contact is connected with the signal source signal CA terminal.

[0072] For the switching circuit of the three-axis magnetic compensation signal. The X-axis magnetic compensation signal is switched by the relay K31. The first movable contact of the K31 is connected with the X_IN terminal of the X-axis magnetic compensation signal collected from the detection object. The first normally closed contact of the K31 is connected with the second normally closed contact of the K31. The first normally open contact of the K31 is connected with the input terminal XB of the X-axis amplification circuit. The output terminal XP of the X-axis amplification circuit is connected with the second normally open contact of the K31. The second movable contact of the K31 is connected with the X terminal of the first sampling channel.

[0073] The Y-axis magnetic compensation signal is switched by the relay K32. The first movable contact of the K32 is connected with the Y_IN terminal of the Y-axis magnetic compensation signal collected from the detection object. The first normally closed contact of the K32 is connected with the second normally closed contact of the K32. The first normally open contact of the K32 is connected with the input terminal YB of the Y-axis amplification circuit. The output terminal YP of the Y-axis amplification circuit is connected with the second normally open contact of the K32. The second movable contact of the K32 is connected with the Y terminal of the second sampling channel.

[0074] The Z-axis magnetic compensation signal is switched and controlled by the relay K33 and part of the relay K35. The first movable contact of K33 is connected to the Z_IN terminal of the Z-axis magnetic compensation signal collected from the detection object. The first normally closed contact of K33 is connected to the second normally closed contact of K33. The first normally open contact of K33 is connected to the input terminal ZB of the Z-axis amplification circuit. The first output terminal ZP of the Z-axis amplification circuit is connected to the second normally open contact of K33. The second movable contact of K33 is connected to the Z terminal of the third sampling channel. As a further optional improvement, a one-stage amplification switching circuit can be connected between the second movable contact of K33 and the Z terminal, so that the Z-axis magnetic compensation signal can be selectively amplified by two stages. That is, the second movable contact of K33 is connected to the second normally closed contact of K35. The second normally open contact of K35 is connected to the second output terminal ZZ of the Z-axis amplification circuit. The second movable contact of K35 is connected to the Z terminal of the third sampling channel.

[0075] For the amplification circuit of the three-axis magnetic compensation signal, the amplification circuit of the X-axis magnetic compensation signal is as follows. The input terminal XB is connected to ground through a resistor R231 and to the non-inverting input terminal of an operational amplifier U53A (OPA2191) through a resistor R230. The inverting input terminal of the operational amplifier U53A is connected to ground through a resistor R233 and to the output terminal of the operational amplifier U53A through a resistor 234. The output terminal is connected to the output terminal XP through a resistor R232.

[0076] The amplification circuit of the Y-axis magnetic compensation signal is as follows. The input terminal YB is connected to ground through a resistor R241 and to the non-inverting input terminal of an operational amplifier U53B (OPA2191) through a resistor R239. The inverting input terminal of the operational amplifier U53B is connected to ground through a resistor R237 and to the output terminal of the operational amplifier U53B through a resistor 235. The output terminal is connected to the output terminal YP through a resistor R238.

[0077] The amplification circuit of the Z-axis magnetic compensation signal is as follows. The input terminal ZB is connected to ground through a resistor R251 and to the non-inverting input terminal of an operational amplifier U54A (OPA2191) through a resistor R248. The inverting input terminal of the operational amplifier U54A is connected to ground through a resistor R250 and to the output terminal of the operational amplifier U54A through a resistor 253. The output terminal is connected to the first output terminal ZP through a resistor R249. The first output terminal ZP is connected to the non-inverting input terminal of an operational amplifier U54B through a resistor R271. The inverting input terminal of the operational amplifier U54B is connected to ground through a resistor R273 and to the output terminal of the operational amplifier U54B through a resistor 274. The output terminal is connected to the second output terminal ZZ through a resistor R272.

[0078] As a specific embodiment, as shown in Figure 8 The amplitude detection module includes a signal conditioning circuit, a rectifier circuit and a filter circuit connected in sequence. The signal conditioning circuit amplifies or attenuates the heating signal through the combination of the third operational amplifier and different feedback resistors. The rectifier circuit rectifies the conditioned signal through a half-wave rectifier and then outputs the signal to the filter circuit through a fourth operational amplifier for inversion processing. The filter circuit is an RC low-pass filter circuit, which outputs a direct current signal in linear relationship with the peak value of the heating signal.

[0079] It should be noted that the heating signal itself is a sinusoidal signal with a frequency of 400 kHz and an amplitude varying between 0 and 12 V. Since the sampling frequency of the signal sampling module is only 20 kHz, which is much lower than the frequency of the heating signal, it is not possible to directly sample the original high-frequency signal. Therefore, the amplitude detection module circuit is designed to rectify and filter the heating signal, converting it into a direct current voltage signal in linear relationship with the peak amplitude for the signal sampling module to sample. The operational amplifiers in this circuit are all of the LT1122CS8 type.

[0080] Specifically, the entire circuit mainly consists of a signal conditioning circuit, a rectifier circuit, and a filter circuit. The heating signal is first conditioned by the inverting operational amplifier with U19 as the core. Different feedback resistor combinations are switched through relays K34 and K36 to achieve amplification or attenuation of different amplitude signals, ensuring that the direct current voltage signal output by the amplitude detection module is not too large or too small to exceed the detection range of the signal sampling module.

[0081] The heating signal HEAT terminal is connected to the moving contact of relay K36, the normally closed contact of relay K36 is connected to the first moving contact of relay K34, the normally open contact of relay K36 is connected to the second moving contact of relay K34, and the two normally open contacts and two normally closed contacts of relay K34 are connected to the inverting input terminal of operational amplifier U19 through four different resistors; the non-inverting input terminal of operational amplifier U19 is connected to ground through resistor R77, and the inverting input terminal of operational amplifier U19 is connected to the output terminal.

[0082] The conditioned signal is sent to the precision rectifier circuit with operational amplifier U5 and operational amplifier U29 as the core. This part uses the combination of operational amplifier and high-speed small signal diode (1N4148) to eliminate the 0.7V conduction voltage drop of ordinary diode rectification, so that even low-amplitude signals can achieve high-precision rectification. Operational amplifier U5 constitutes a precision half-wave rectifier, which rectifies the input high-frequency sinusoidal signal unidirectionally, and then inverts the signal by operational amplifier U29, so that the output signal can correctly reflect the peak value change of the input signal.

[0083] The conditioned signal is connected to the inverting input of operational amplifier U5 through resistor R240, and connected to the non-inverting input of operational amplifier U29 through resistor R22; the non-inverting input of operational amplifier U5 is connected to ground through resistor R24, and the inverting input of operational amplifier U5 is connected to the anode of diode D37 and one end of resistor R258; the cathode of diode D37 is connected to the output of operational amplifier U5 and the anode of diode D36, and the anode of diode D36 is connected to the non-inverting input of operational amplifier U29; the other end of resistor R258 is connected to the inverting input of operational amplifier U29 and the output of operational amplifier U29.

[0084] The rectified signal is smoothed by an RC low-pass filter network composed of R242, R246 and C277, high-frequency components are filtered out, and only the DC component reflecting the trend of peak value change is retained, thereby realizing effective extraction of the original high-frequency signal envelope. Finally, the output voltage is led out from the HA end and sent into the signal sampling module for sampling, thereby completing indirect measurement of the heating signal peak value.

[0085] As a specific embodiment, the signal shaping module includes a comparator; after the heating signal is coupled through the second capacitor, it is clamped to a safe level by a limiting diode, and the clamped signal is input to the inverting input of the comparator through the fifth resistor; the non-inverting input of the comparator inputs a reference level; and the output of the comparator outputs a square wave signal to the main control module after current limiting by the sixth resistor.

[0086] It should be noted that when multiple magnetometer probes are heated simultaneously, the consistency of the heating frequency needs to be ensured, and the error should be less than or equal to 0.025% under the condition of 400 kHz. If the heating signal frequency is inconsistent among different magnetometer probes, low-frequency noise will be generated, affecting the detection accuracy of the magnetic field. Therefore, the frequency of the heating signal needs to be detected.

[0087] Specifically, as shown in Figure 8 To realize accurate detection of the 400 kHz heating signal frequency, the original sine wave is processed in the signal shaping mode in this embodiment, so as to adapt to the digital input characteristics of the main control module MCU. Since the MCU cannot directly process analog sine waves, it must be converted into a square wave with clear high and low levels first. This processing is completed by a high-frequency comparator circuit, and the core device is TLV9024IDR operational amplifier U30.

[0088] The 400 kHz sine signal at the input end is input from the left side HEAT and coupled into the shaping circuit through capacitor C320. The capacitor plays a role in blocking direct current, preventing the later-stage circuit from being affected by direct current bias. The signal is then clamped to a safe level by limiting diodes D38 and D39, preventing instantaneous overvoltage from damaging the comparator or affecting the comparison result. The clamped signal is input to the inverting input of comparator U30 through R275, and compared with the reference level at the non-inverting input.

[0089] The non-inverting input of comparator U30 is supplied with a reference voltage level (here set to 1.65V) by a resistor-capacitor network (R264, R265, R266, and C321) to achieve symmetrical comparison of the input signal. When the instantaneous voltage of the input sine wave exceeds the reference voltage, the comparator outputs a high level; otherwise, it outputs a low level, thereby converting the continuous sine wave signal into a corresponding 400kHz square wave signal. This output signal is current-limited by R257 and then output to the main control module via the HEATF terminal.

[0090] In order to enhance the stability and anti-interference capability of the shaped signal, resistor R263 is used to form a feedback path between the output terminal and the non-inverting input terminal of the comparator U30, so that the comparator has a certain hysteresis characteristic, thereby avoiding output jitter caused by noise near the zero point of the input signal and improving the stability of the square wave signal.

[0091] The resulting 400kHz square wave signal is then output from the HEATF terminal and fed into the digital input port of the main control module (MCU). The MCU accurately calculates the heating signal frequency by counting high-level pulses, implementing a frequency detection function. Tests have shown that frequency detection accuracy can reach 0.005%.

[0092] As a specific example, Figure 9 In the switching multiplexing module shown, the command sent from the main control module is output through the shift register, and then the Darlington transistor drives the control relay array to switch the signal channel selection; The relay array includes a first relay array for simulating current output and noise test switching, and a second relay array for selectively detecting one of several channels of the detection object; The first relay array includes a plurality of first sub-arrays with the same structure, and each first sub-array corresponds to a channel of a detection object.

[0093] It should be noted that, to achieve the switching and channel selection functions of a simulated PT1000 resistor, the present invention uses a shift register RS595SXTSS16, a Darlington transistor ULN2003A, and a relay array. The main control module's MCU connects to the shift registers in the switching multiplexing module via ports 595_SER, 595_G, 595_RCK, 595_SCK, and 595_SCLR, inputting corresponding on / off control instructions. Each shift register is connected to a corresponding Darlington transistor, which transmits the on / off control instructions issued by the main control module through each output pin of the Darlington transistor, controlling the on / off switching of the corresponding relay.

[0094] Furthermore, in the first subarray, the simulated magnetometer photocurrent is input into the moving contact of the fifth relay, the normally closed contact of the fifth relay is grounded via the seventh resistor, the normally open contact of the fifth relay is connected to the normally open contact of the first relay, the moving contact of the first relay outputs the simulated magnetometer photocurrent to the detection object, the normally closed contact of the first relay is connected to the normally open contacts of the second relay to the fourth relay respectively, and the moving contacts of the second relay to the fourth relay are respectively connected to the three-axis magnetic compensation signals of the detection object and output by the corresponding normally closed contacts.

[0095] Specifically, such as Figure 10 FIG. 1 is a partial schematic diagram of the first relay array in the switching multiplexing module and a schematic diagram of the relay control circuit. In the circuit of the switching multiplexing module of this embodiment, the output pin of the Darlington transistor is connected as shown in FIG. Figure 10 The switching control relay array (first relay array) for analog current output and noise test, the relay array for detection object channel selection (second relay array) and Figure 11 The third relay array for selecting the analog resistance and the fourth relay array for selecting the channel of the signal source signal are shown. At the same time, the connection terminals corresponding to the detection objects in all relay arrays are connected through Figure 12 The patch cord shown is connected to the switching multiplexing module of this embodiment.

[0096] The first relay array includes control circuits for 12 relays, K1 to K12, and is controlled on and off via Darlington transistor outputs PD1AL, XA, YA, ZA, PD1A, PD2A, PD1BL, XB, YB, ZB, PD1B, and PD2B. The second relay array includes control circuits for six relays, K16 to K21, and is controlled on and off via Darlington transistor outputs XYA, XYB, XYC, ZHA, ZHB, and ZHC.

[0097] The third relay array includes control circuits for nine relays, K13 through K15 and K22 through K27, and is controlled on and off via Darlington transistor outputs PTA, PTB, PTC, 1.1K_CON, 1.2K_CON, 1.37K_CON, 1.47K_CON, 1.5K_CON, and 1.54K_CON. The fourth relay array includes control circuits for two relays, K28 and K29, and is controlled on and off via Darlington transistor outputs K28 and K29.

[0098] The first relay array includes a plurality of first sub-arrays with the same structure, each sub-array corresponding to a channel of the detection object. Since the structures of the first sub-arrays are the same, only one of them is used as an example for description.

[0099] The output end PD11OUT of the first analog unit in the current simulation module is connected with the first movable contact of the relay K5, the first normally closed contact of the K5 is connected with the ground through the resistor R12, the first normally open contact of the K5 is connected with the first normally open contact of the relay K1, the first movable contact of the relay K1 outputs the analog current to the detection object through the PD11 end. The first normally closed contact of the relay K1 is connected with the first normally open contact of the relays K2, K3 and K4 respectively, the relay K2 connects the X-axis magnetic compensation signal of the first channel of the detection object through the first movable contact and the first normally closed contact, the relay K3 connects the Y-axis magnetic compensation signal of the first channel of the detection object through the first movable contact and the first normally closed contact, the relay K4 connects the Z-axis magnetic compensation signal of the first channel of the detection object through the first movable contact and the first normally closed contact. The output end PD21OUT of the second analog unit is connected with the first movable contact of the relay K6, the first normally closed contact of the K6 is connected with the ground through the resistor R20, the first normally open contact of the K6 outputs the analog current to the detection object through the PD21 end. The first contact pair (movable contact, normally open contact and normally closed contact) of the relays K1 to K6 is connected with the second channel of the detection object by the current simulation module and the signal sampling module.

[0100] When the first normally open contact and the first movable contact of the relay K5 are connected, and the first normally open contact and the first movable contact of the relay K1 are connected, the PD11OUT is connected with the PD11, and the analog probe outputs the analog current to the detection object; when the first normally closed contact and the first movable contact of the relay K1 are connected, and the first movable contact and the first normally open contact of the relays K2 to K4 are connected, the loopback test noise is performed.

[0101] The second contact pair of the relays K1 to K6 is connected with the second channel of the detection object by the current simulation module and the signal sampling module; the first contact pair of the relays K7 to K12 is connected with the third channel of the detection object by the current simulation module and the signal sampling module; the second contact pair of the relays K7 to K12 is connected with the fourth channel of the detection object by the current simulation module and the signal sampling module.

[0102] For the second relay array, taking the X-axis magnetic compensation signal of the four channels of the detection object as an example, the X_IN end connected with the signal sampling module is connected with the first movable contact of the relay K18, the first normally open contact of the relay K18 is connected with the first movable contact of the relay K17, the first normally closed contact of the relay K18 is connected with the first movable contact of the relay K16, and the X-axis magnetic compensation signal of the four channels of the detection object is connected through the first contact pair of the relays K16 and K17.

[0103] The second contact pair of the relays K16 to K18 connects the signal sampling module with the Y-axis magnetic compensation signals of the four channels of the detection object; the first contact pair of the relays K19 to K21 connects the signal sampling module with the Z-axis magnetic compensation signals of the four channels of the detection object; the second contact pair of the relays K19 to K21 connects the signal sampling module with the heating signals of the four channels of the detection object; the two groups of contacts of the relays K13 to K15 connect the PTP end and the PTN end of the analog resistance gating to the corresponding signals of the four channels of the detection object. Figure 11 The PTP end and the PTN end of the analog resistance gating are connected to the corresponding signals of the four channels of the detection object.

[0104] As a specific embodiment, as shown in Figure 13 the specific operation steps of the automatic test device include: after the device is started, waiting for the host computer to send instructions; if the host computer sends a signal source signal measurement instruction, a three-axis magnetic compensation signal measurement instruction, and a heating signal measurement instruction, the signal sampling module will collect voltage data at a frequency of 20 KHz and upload the data to the host computer, wherein the heating signal frequency is detected through TIM1 / 2, and if the heating signal is too small or too large, the host computer can send an instruction to the amplitude detection module to amplify or attenuate the signal; if the host computer sends a signal generator instruction, the current simulation module will output a current waveform according to the configuration; if the host computer sends a noise test instruction, the relay array will enable the corresponding channel according to the configuration. The host computer automatically controls the automatic test device to sequentially complete PD AC / DC detection, temperature detection, three-axis magnetic compensation detection, heating signal detection, noise detection, and signal source function detection. During the test, the host computer will compare the test data with the reasonable data range set in advance, and if the test data exceeds the reasonable range, it will be determined as unqualified; after the test is completed, the test results will be displayed on the host computer, and the test items that pass will be displayed in green and the test items that fail will be displayed in red. The user can export the test report and complete the test.

[0105] Optionally, in a cost-sensitive application scenario, the high-resolution 16-bit ADC (such as LTC2357) in the above embodiment can be replaced by a lower-resolution 12-bit ADC (such as ADS7818 or an internal ADC module of STM32). This can effectively reduce the system hardware cost and power consumption, and is suitable for test environments with low requirements for noise detection accuracy. Although the measurement accuracy and dynamic range are sacrificed to some extent, the basic functions of the acquisition board card, such as heating signal and magnetic compensation signal, can still be detected and verified.

[0106] In applications requiring higher flexibility or portability, wireless communication technologies such as Bluetooth, ZigBee, Wi-Fi, etc. can be used instead of USB2.0 or wired Ethernet communication mode. It is suitable for remote control and data acquisition in distributed testing and mobile scenarios. Although wireless transmission has problems such as limited bandwidth, unstable delay, etc., it is not suitable for high-frequency and high-throughput data scenarios, but through reasonable configuration of communication protocol and data compression method, most functional control and data backhaul requirements can still be met.

[0107] In addition to the timer counting method, the software edge detection method or the external special frequency counting chip (such as TDC-GPX) can also be used to detect the frequency of the heating signal. The resolution of the frequency measurement can be further improved or the MCU resource occupation can be reduced, which is suitable for extreme precision requirements or ultra-high speed signal frequency detection scenarios.

[0108] The above embodiments are further elaborated and described to facilitate understanding, and are not any limitation on the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An automated testing device for an array magnetometer electronic control system, characterized in that: The analog probe comprises: The current simulation module simulates the magnetometer photocurrent output to the detection object according to the instruction of the host module; The signal sampling module samples the three-axis magnetic compensation signal and the heating signal or the signal source signal and transmits them to the host module; The amplitude detection module converts the heating signal into a direct current signal which is linearly related to the signal peak and inputs the signal sampling module; The signal shaping module converts the heating signal into a square wave signal and inputs the host module for frequency detection; The switching and multiplexing module selects and switches the signal channel according to the instruction of the host module.

2. The automated test equipment for an array magnetometer electronic control system of claim 1, wherein, The arrayed magnetometer electric control system is connected with the analog probe through the adapter line, and a corresponding number of analog probes are connected according to the number of channels of the detection object. The current simulation module comprises a first simulation unit and a second simulation unit with the same circuit structure; 3. The automated test equipment for an electric control system of an array magnetometer according to claim 1 or 2, characterized in that, The first simulation unit comprises a digital-to-analog conversion chip with a plurality of independent output channels, each of which is connected with a constant current source circuit and outputs the simulated magnetometer photocurrent from the output end of the constant current source circuit; In the constant current source circuit, the independent output channel is connected with one end of the second resistor, one end of the first capacitor and the positive input end of the second operational amplifier through the first resistor; the other end of the first capacitor is grounded, and the other end of the second resistor is connected with the output end and the inverting input end of the first operational amplifier; the inverting input end of the second operational amplifier is grounded through the third resistor and connected with the output end of the second operational amplifier through the parallel resistor-capacitor; The output end of the second operational amplifier is connected with the positive input end of the first operational amplifier through the fourth resistor as the output end of the constant current source circuit. The signal sampling module comprises an analog-to-digital conversion chip comprising at least four sampling channels, and a switching circuit and an amplification circuit corresponding to the three-axis magnetic compensation signal; 4. The automated test equipment for an electric control system of an array magnetometer according to claim 1 or 2, characterized in that, The first to third sampling channels in the analog-to-digital conversion chip respectively collect the three-axis magnetic compensation signal; the fourth sampling channel detects the heating signal amplitude or the signal source signal and switches the two detection signals through a relay; For the magnetic compensation signal of any axis, the circuit gain of the analog probe is automatically adjusted according to the size of the magnetic compensation signal output by the arrayed magnetometer electric control system, and the magnetic compensation signal is amplified or attenuated before being input into the signal sampling module for sampling. The data processing of the three-axis magnetic compensation signal comprises:

5. The automated test equipment for an array magnetometer electronic control system of claim 4, wherein, The actual detection result is obtained by comparing the detection value collected by the signal sampling module with the circuit gain; The signal frequency of any axis is calculated, the actual voltage value of the axis is the voltage value of the axis minus the voltage bias of the axis, the zero crossing point of the actual voltage value is detected and recorded, and the interval between adjacent zero crossing points is a period, and the reciprocal of the period is the frequency; The three-axis voltage signal and the frequency are uploaded to the host computer, the three-axis voltage signal is converted into a current value, and compared with the preset current range, if it exceeds the preset current range, it is determined as unqualified. ​ The data processing of the signal source signal comprises: collecting actual detection results by the signal sampling module; calculating the frequency of the signal source signal in the same manner as the three-axis magnetic compensation signal; uploading the signal source voltage signal and the frequency to the host computer and comparing with the preset voltage range, and determining unqualified if exceeding the preset voltage range.

6. The automated test equipment for an electronic control system of an array magnetometer according to claim 1 or 2 or 5, characterized in that, The amplitude detection module comprises a signal conditioning circuit, a rectifier circuit and a filter circuit connected in sequence. The signal conditioning circuit amplifies or attenuates the heating signal through the combination of the third operational amplifier and different feedback resistors. The rectifier circuit performs one-way rectification on the conditioned signal through a half-wave rectifier and then performs inverse processing through the fourth operational amplifier and outputs to the filter circuit. The filter circuit is an RC low-pass filter circuit, which outputs a direct current signal in linear relationship with the peak value of the heating signal.

7. The automated test equipment for an array magnetometer electronic control system of claim 6, wherein, The data processing of the heating signal comprises: obtaining the frequency of the heating signal and converting the heating signal of the frequency into a direct current signal in linear relationship with the peak value of the heating signal; performing device calibration, collecting the amplitude detection values of a plurality of heating signals detected by the analog probe and the corresponding actual amplitude values, and fitting to obtain a calibration relationship between the two; the signal sampling module collects the voltage value of the heating signal, and the voltage value divided by the circuit gain and multiplied by 2 is taken as the amplitude detection value; the actual amplitude value is obtained by using the calibration relationship; the actual amplitude value and the frequency of the heating signal are uploaded to the host computer, and the host computer compares the actual amplitude value with the preset amplitude range, and determines unqualified if exceeding the preset amplitude range.

8. The automated test equipment for an electric control system of an array magnetometer according to claim 1 or 2 or 5 or 7, characterized in that, The signal shaping module comprises a comparator; after the heating signal is coupled through the second capacitor, it is clamped to a safe level through a limiting diode, and the clamped signal is input to the inverting input terminal of the comparator through the fifth resistor; the non-inverting input terminal of the comparator inputs a reference level; The output terminal of the comparator outputs a square wave signal to the main control module after current limiting through the sixth resistor.

9. The automated test equipment for an electric control system of an array magnetometer according to claim 1 or 2 or 5 or 7, characterized in that, In the switching multiplexing module, the instructions from the main control module are output through the displacement register, and then drive and control the on-off of the relay array through the Darlington tube to select and switch the signal channel; The relay array comprises a first relay array for switching between analog current output and noise testing, and a second relay array for selecting one of a plurality of channels of the detection object for detection; The first relay array comprises a plurality of first sub-arrays with the same structure, and each first sub-array corresponds to a channel of a detection object.

10. The automated test equipment for an array magnetometer electronic control system of claim 9, wherein, In the first sub-array, the analog magnetometer photocurrent is input to the moving contact of the fifth relay, the normally closed contact of the fifth relay is connected to ground through the seventh resistor, the normally open contact of the fifth relay is connected to the normally open contact of the first relay, the moving contact of the first relay outputs the analog magnetometer photocurrent to the detection object, the normally closed contact of the first relay is connected to the normally open contacts of the second to fourth relays, and the moving contacts of the second to fourth relays are connected to the three-axis magnetic compensation signals of the detection object and output by the corresponding normally closed contacts.

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