Self-detection calibration circuit for analog quantity output board card and analog quantity output board card

Abstract

The invention relates to the technical field of detection circuits, and discloses a self-detection calibration circuit for an analog quantity output board card and the analog quantity output board card, and the self-detection calibration circuit comprises a signal recovery unit which is provided with a self-detection AI port, the self-detection AI port is configured to recover a first detection signal output by the AO port to generate a first sampling signal; the channel selection unit is configured to connect the AO port and the self-detection AI port so as to send the first sampling signal to the AO port; the controller is configured to control the AO signal output unit to generate the first detection signal, compare the first detection signal with the first sampling signal, and detect whether the AO port is abnormal or not according to the comparison result. Through the internally integrated self-detection calibration circuit, whether the function of the analog quantity output board card is normal or not can be detected in time and calibration is carried out, the detection and calibration difficulty is reduced, and the reliability of the analog quantity output board card is improved.

Description

Technical Field

[0001] The present application relates to the technical field of detection circuits, and in particular to a self-detection calibration circuit for an analog output board and an analog output board. Background Art

[0002] As an important interface in industrial control systems, analog output interfaces are mainly used to receive analog signals corresponding to physical quantities of industrial equipment during operation, thereby providing a data basis for condition monitoring of industrial control systems. Therefore, the accuracy, stability and reliability of analog output interfaces are crucial to the normal operation of the entire industrial control system.

[0003] In the related art, the analog output interface is usually tested and calibrated for its analog output function through external testing and calibration equipment. However, such external testing and calibration equipment not only increases the equipment and labor generation, but may also increase the difficulty of detecting the analog output interface in harsh industrial environments. For example, external environmental factors such as electromagnetic interference, high temperature or high humidity may affect the signal transmission effect between the external testing and calibration equipment and the analog output interface, thereby affecting the detection and calibration effect of the analog output interface. Summary of the invention

[0004] The present application provides a self-detection and calibration circuit for an analog output board and an analog output board, which solves the problem that in a relatively harsh industrial environment, a self-detection and calibration circuit is integrated inside the analog output board to realize AO (analog input, Analog Output) port self-detection, so that the function of the analog output board can be detected in time and calibrated, thereby reducing the difficulty of detecting and calibrating the function of the analog output board in a harsh industrial environment and improving the reliability of the analog output board.

[0005] In order to achieve the above objectives, the main technical solutions adopted in this application include:

[0006] In a first aspect, an embodiment of the present application provides a self-detection calibration circuit for an analog output card, wherein the analog output card is provided with multiple groups of mutually independent AO ports, and the self-detection calibration circuit comprises:

[0007] A signal collection unit, wherein the signal collection unit is provided with a self-detection AI port, and the self-detection AI port is configured to collect a first detection signal output by the AO port to generate a first sampling signal, wherein the first detection signal is provided by the AO signal output unit of the analog output board;

[0008] a channel selection unit, the channel selection unit being configured to connect the AO port and the self-detection AI port to send the first sampling signal to the AO port;

[0009] A controller is configured to control the AO signal output unit to generate the first detection signal, compare the first detection signal with the first sampling signal, and detect whether an abnormality occurs in the AO port according to the comparison result.

[0010] The self-detection calibration circuit proposed in the embodiment of the present application utilizes the signal output function inside the analog output board to send the first detection signal to the AO port, and obtains the first sampling signal of the AO port through the signal recovery unit and the channel selection unit, so as to compare the first sampling signal with the original first detection signal through the controller, thereby timely detecting whether an abnormality occurs in the AO port. Therefore, the embodiment of the present application forms a self-detection feedback mechanism inside the analog output board by integrating the self-detection calibration circuit in the analog output board, which can effectively avoid the problem of difficulty in AO port detection caused by interference from external environmental factors in harsh environments, and not only effectively suppresses the interference of external environmental changes on AO port detection, ensuring the accuracy and real-time nature of the detection results, but also can reduce the time cost and labor cost of detection in harsh environments, greatly improving the detectability and reliability of the AO port.

[0011] Optionally, in some embodiments of the present application, the signal recovery unit includes:

[0012] A first amplifying circuit, wherein the first amplifying circuit is configured to amplify the analog quantity on the AO port, wherein the input end of the first amplifying circuit is configured as the self-detection AI port;

[0013] The analog-to-digital conversion circuit is configured to perform analog-to-digital conversion on the analog quantity after differential amplification by the first amplifier circuit to obtain the first sampling signal, and send the first sampling signal to the controller through the I2C bus.

[0014] Optionally, in some embodiments of the present application, the first amplification circuit includes:

[0015] a first amplifier, wherein a positive input terminal of the first amplifier is connected to an AI+ port in the self-detection AI port via a first protection circuit, and a negative input terminal of the first amplifier is connected to an output terminal of the first amplifier;

[0016] a second amplifier, wherein a positive input terminal of the second amplifier is connected to an AI-port in the self-detection AI port via a second protection circuit, and a negative input terminal of the second amplifier is connected to an output terminal of the second amplifier;

[0017] A third amplifier, wherein the positive input terminal of the third amplifier is connected to the output terminal of the second amplifier, the negative input terminal of the third amplifier is connected to the output terminal of the first amplifier, and the output terminal of the third amplifier is connected to the input terminal of the analog-to-digital conversion circuit through a first current limiting circuit.

[0018] The embodiment of the present application realizes high-precision acquisition of the analog quantity on the AO port through the signal acquisition unit to facilitate subsequent signal comparison and abnormal state detection, and suppresses external noise interference through the multi-stage differential amplification of the first amplifier circuit, thereby improving the signal acquisition accuracy and anti-interference ability.

[0019] Optionally, in some embodiments of the present application, the channel selection unit is configured to cut off the connection between the AO port and the external load and connect the AO port with the self-detection AI port when the analog output board is in self-detection mode.

[0020] Optionally, in some embodiments of the present application, the channel selection unit includes a multiplexer, wherein an input end of the multiplexer is connected to the self-detection AI port, a first output end of the multiplexer is connected to a first relay switch between the AO port and the self-detection AI port, and a second output end of the multiplexer is connected to the AO port and a second relay switch of the external load.

[0021] The embodiment of the present application realizes free switching of the AO port between the external load and the self-detection AI port inside the board by setting a channel selection unit. Therefore, the setting of the above-mentioned self-detection calibration circuit will not affect the normal function of the AO port to output external signals. At the same time, it can cut off the connection between the AO port and the external load in the self-detection mode to avoid external interference, and connect the AO port to the self-detection AI port, so that the AO port can perform internal self-detection, which helps to quickly switch the AO port between the normal working mode and the self-detection mode.

[0022] Optionally, in some embodiments of the present application, the AO port adopts a redundant design, wherein the AO port includes a primary AO port and a backup AO port;

[0023] The channel selection unit is also configured to, when the main AO port is connected to the external load, simultaneously connect the connection between the main AO port and the backup AO port and the external load based on a preset cycle, compare the analog quantities on the main AO port and the backup AO port, and determine that the analog output board enters the self-detection mode based on the comparison result.

[0024] The embodiment of the present application performs redundant design on the AO port, and through the comparison mechanism between the redundant ports, possible abnormalities or errors in the main AO port can be detected. Once the detection result shows that the signal difference between the main AO port and the backup AO port exceeds the allowable range, it is automatically determined whether the analog output board enters the self-detection mode according to the comparison result to further calibrate the accuracy and stability of the port. Therefore, on the one hand, the reliability and fault tolerance of the AO port can be enhanced, and on the other hand, the function of entering the self-detection mode can be realized, thereby reducing human intervention and detection time, and improving the self-detection efficiency and reliability of the analog output board.

[0025] Optionally, in some embodiments of the present application, the self-detection calibration circuit further includes a signal calibration unit, and the signal calibration unit is configured to determine a calibration coefficient according to a ratio of the first detection signal to the first sampling signal when an abnormality occurs in the AO port.

[0026] Optionally, in some embodiments of the present application, the signal calibration unit is further configured to send the calibration coefficient to the controller and drive a signal calibration program of the controller to calibrate the analog quantity on the AO port based on the calibration coefficient.

[0027] The embodiment of the present application realizes automatic calibration of the AO port through a signal calibration unit. If an abnormality occurs in the AO port, the signal calibration unit will determine the calibration coefficient according to the ratio of the first detection signal to the first sampling signal to reflect the deviation between the signal input through the AO port and the actual input signal, thereby providing a basis for the calibration of the AO port and greatly improving the stability of the AO port.

[0028] In a second aspect, an embodiment of the present application provides an analog output board, the analog output board comprising:

[0029] A plurality of mutually independent AO signal output units, wherein the output end of each of the AO signal output units is configured as an AO port;

[0030] According to the self-detection calibration circuit described in the above embodiment, the self-detection calibration circuit configures the circuit corresponding to the AO port.

[0031] The analog output card proposed in the embodiment of the present application detects the analog receiving function of the AO port through the above-mentioned self-detection calibration circuit, so as to timely find out whether the AO port has any abnormality. Therefore, the embodiment of the present application forms a self-detection feedback mechanism inside the analog output card by integrating the self-detection calibration circuit in the analog output card, which can effectively avoid the problem of difficulty in AO port detection caused by interference from external environmental factors in harsh environments, and effectively suppresses the interference of external environmental changes on AO port detection, ensuring the accuracy and real-time nature of the detection results, and can also reduce the time cost and labor cost of detection in harsh environments, greatly improving the detectability and reliability of the AO port.

[0032] Optionally, the AO signal output unit adopts a redundant design, and the AO signal input unit includes a main AO signal input unit and a backup AO signal input unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A structural block diagram of a self-detection and calibration circuit for an analog output card proposed in an embodiment of the present application;

[0035] Figure 2 A circuit structure diagram of a signal recovery unit proposed in an embodiment of the present application;

[0036] Figure 3 This is a schematic diagram of the structure of the AO port redundancy design proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0038] As an important component of industrial control systems, analog output interfaces are mainly used to receive analog signals from sensors, actuators and other industrial equipment during operation, such as physical quantities such as equipment operating current, equipment operating voltage, and equipment operating temperature collected by sensors. With the expansion of the scale and increase of complexity of automation control systems, higher requirements are placed on the reliability and detectability of analog output interfaces.

[0039] In the related art, the analog output interface usually uses external detection equipment to detect the input function of the analog output interface. This detection method has many shortcomings. First, relying on external detection equipment requires adding additional hardware modules, which increases equipment and labor costs, and reduces the real-time detection of the working status of the analog output interface, resulting in low detection efficiency.

[0040] In addition, in outdoor industrial environments such as ship systems, there are external factors such as high temperature and humidity, salt spray, mold, impact, vibration, and electromagnetic interference, which increase the difficulty of detecting the analog output interface and may affect the effective detection of the analog output interface by external detection equipment, thereby reducing the stability, reliability, and detectability of the analog output interface.

[0041] In this embodiment, a self-detection calibration circuit for an analog output card is provided, which can be used in industrial control systems, such as programmable logic controllers (PLCs) such as ship systems and electrical equipment control systems.

[0042] like Figure 1 As shown, the analog output board is provided with multiple groups of mutually independent AO ports 10, and the self-detection calibration circuit 20 includes a signal collection unit 100, a channel selection unit 200 and a controller 300;

[0043] The signal recovery unit 100 is provided with a self-detection AI port, which is configured to recover the first detection signal output by the AO port 10 to generate a first sampling signal, wherein the first detection signal is provided by the AO signal output unit 30 of the analog output board.

[0044] The self-detection calibration circuit 20 provided in this embodiment uses the signal output function inside the analog output board to send the first detection signal to the AO port 10, and obtains the first sampling signal of the AO port through the signal recovery unit 100 and the channel selection unit 200, so as to compare the first sampling signal with the original first detection signal through the controller 300, thereby timely detecting whether an abnormality occurs in the AO port 10. Therefore, the embodiment of the present application forms a self-detection feedback mechanism inside the analog output board by integrating the self-detection calibration circuit 20 in the analog output board, which can effectively avoid the problem of difficulty in detecting the AO port 10 caused by interference from external environmental factors in harsh environments, not only effectively suppressing the interference of external environmental changes on the detection of the AO port 10, ensuring the accuracy and real-time nature of the detection results, but also reducing the time cost and labor cost of detection in harsh environments, greatly improving the detectability and reliability of the AO port 10.

[0045] In order to realize the self-detection of the AO port, the embodiment of the present application sets up a group of self-detection AI ports (including AI+ port and AI- port) on the analog output board. The controller 300 drives the AO signal output unit 30 of the analog output board to output the first detection signal to the AO port 10, and switches the AO port to the only self-detection AI port on the analog output board through the channel selection unit 200, so as to transfer the above-mentioned first detection signal to the signal collection unit 100 and generate a corresponding first sampling signal, which can truly reflect the signal input status on the AO port 10. Finally, the self-detection signal feedback mechanism inside the analog output board is realized by feeding the first sampling signal back to the controller 300.

[0046] Specifically, Figure 2 As shown, in the embodiment of the present application, the signal recovery unit 100 includes a first amplifier circuit 110 and an analog-to-digital conversion circuit 120. The first amplifier circuit 110 is configured to amplify the analog quantity on the AO port, wherein the input end of the first amplifier circuit 110 is configured as the self-detection AI port, including an AI+ port and an AI- port. The analog-to-digital conversion circuit 120 is configured to perform analog-to-digital conversion on the analog quantity after differential amplification by the first amplifier circuit 110 to obtain a first sampling signal, and send the first sampling signal to the controller 300 through the I2C bus.

[0047] Furthermore, if Figure 2 As shown, the first amplifier circuit 110 includes a first amplifier U1, a second amplifier U2 and a third amplifier U3, wherein the positive input terminal of the first amplifier U1 is connected to the AI+ port in the self-detection AI port via the first protection circuit, and the negative input terminal of the first amplifier U1 is connected to the output terminal of the first amplifier U1.

[0048] Specifically, the positive input terminal of the first amplifier U1 passes through the first protection circuit composed of resistors R4 to R6 and a diode D2, and the analog quantity on the AO+ port collected from the AI+ port is amplified, and then input to the negative input terminal of the third amplifier U3 through the current limiting resistor R7. In addition, the positive power supply terminal of the first amplifier U1 is connected to the power supply AV_5V, the negative power supply terminal of the first amplifier U1 is connected to the power supply AV_-5V, and a filter circuit composed of capacitors C4 and C5 is provided between the positive power supply terminal and the ground terminal AGND.

[0049] The positive input terminal of the second amplifier U2 is connected to the AI-port in the self-detection AI port via a second protection circuit, and the negative input terminal of the second amplifier is connected to the output terminal of the second amplifier.

[0050] Specifically, the positive input terminal of the second amplifier U2 passes through the second protection circuit formed by the resistor R8, amplifies the analog quantity on the AO-port collected from the AI-port, and inputs it to the positive input terminal of the third amplifier U3 through the current limiting resistor R9. In addition, the positive power supply terminal of the second amplifier U2 is connected to the power supply AV_5V, the negative power supply terminal of the second amplifier U2 is connected to the power supply AV_-5V, and a filter circuit composed of a resistor R10, a capacitor C6 and a capacitor C7 is provided between the negative power supply terminal and the ground terminal AGND.

[0051] In addition, a protection circuit consisting of a resistor R11 and a TVS tube D3 connected in parallel is provided between the AI+ port and the AI- port.

[0052] The positive input of the third amplifier U3 is connected to the output of the second amplifier U2, the negative input of the third amplifier U3 is connected to the output of the first amplifier U1, and the output of the third amplifier U3 is connected to the input of the analog-to-digital conversion circuit 120 via the first current limiting circuit.

[0053] Specifically, the third amplifier U3 further performs differential amplification on the analog quantity after amplification by the first amplifier U1 and the second amplifier U2 through a feedback circuit composed of a resistor R12 and a resistor R13, so as to improve the signal accuracy and its anti-interference ability. At the same time, the positive power supply terminal of the third amplifier U3 is connected to the power supply AV_5V, and the negative power supply terminal of the third amplifier U3 is connected to the power supply AV_-5V.

[0054] The first amplifier circuit 110 also includes a fourth amplifier U4, wherein a circuit composed of the fourth amplifier U4, a resistor R14, a resistor R15 and a capacitor C8 is used to generate a reference voltage Vref_2.2V and send it to the positive input terminal of the third amplifier U3, and at the same time, the positive power supply terminal of the fourth amplifier U4 is connected to the power supply AV_5V, and the negative power supply terminal of the fourth amplifier U4 is connected to the power supply AV_-5V.

[0055] The embodiment of the present application realizes high-precision acquisition of the analog quantity on the AO port 10 through the signal acquisition unit to facilitate subsequent signal comparison and abnormal state detection, and suppresses external noise interference through the multi-stage differential amplification of the first amplifier circuit 110, thereby improving the signal acquisition accuracy and anti-interference ability.

[0056] The third amplifier U3 outputs the analog quantity after differential amplification to the IN-pin and IN+pin of the analog-to-digital conversion chip U5 in the analog-to-digital conversion circuit 120, wherein the analog-to-digital conversion circuit 120 also includes a peripheral circuit of the analog-to-digital conversion chip U5 composed of resistors R16 to R19 and capacitors C9 to C12. The analog quantity output by the third amplifier U2B is converted into a digital signal through the analog-to-digital conversion chip U5, and then sent to the controller 300 through the SDA pin and the SCL pin in the form of I2C bus transmission.

[0057] In some embodiments of the present application, the channel selection unit 200 is configured to cut off the connection between the AO port 10 and the external load and connect the AO port 10 to the self-detection AI port when the analog output board is in the self-detection mode.

[0058] Furthermore, the channel selection unit 200 includes a multiplexer (MUX), wherein an input end of the multiplexer is connected to the above-mentioned self-detection AI port, a first output end of the multiplexer is connected to a first relay switch K1 between the AO port 10 and the self-detection AI port, and a second output end of the multiplexer is connected to the AO port 10 and a second relay switch K2 of an external load.

[0059] Specifically, when the self-detection AI port receives the above-mentioned first detection signal, it indicates that the AO port needs to be self-detected. At this time, the multiplexer drives the first relay switch K1 to close, and drives the second relay switch K2 to open, so as to switch the first detection signal to the self-detection AI port. When the self-detection AI port does not receive the above-mentioned first detection signal, it indicates that the AO port does not need to be self-detected at present. At this time, the multiplexer drives the first relay switch K1 to open, and drives the second relay switch K2 to close, so that the AO port can output analog quantity normally.

[0060] Therefore, the embodiment of the present application realizes free switching of the AO port 10 between the external load and the self-detection AI port inside the board by setting the channel selection unit 200. Therefore, the setting of the above-mentioned self-detection calibration circuit will not affect the normal function of the AO port 10 to output external signals. At the same time, it can cut off the connection between the AO port 10 and the external load in the self-detection mode to avoid external interference, and connect the AO port 10 to the self-detection AI port, so that the AO port 10 can perform internal self-detection, which helps the AO port 10 to quickly switch between the normal working mode and the self-detection mode.

[0061] In the embodiment of the present application, the AO port 10 adopts a redundant design, wherein the AO port 10 includes an active AO port 11 and a standby AO port 12 .

[0062] On this basis, the controller is also configured to drive the channel selection unit 200 to simultaneously connect the main AO port 11 and the backup AO port 12 to the external load based on a preset cycle when the main AO port 12 is connected to the external load, and compare the analog quantities on the main AO port 11 and the backup AO port 12, and determine that the analog output board enters the self-detection mode based on the comparison result.

[0063] Figure 3 The schematic diagram of the redundant design is shown. When the self-detecting AI port does not receive the first detection signal, the multiplexer drives the second relay switch K2 to close, so that the main AO port 11 normally receives the analog quantity sent by the external load 30, and drives the third relay switch K3 between the backup AO port 12 and the external load 30 based on a preset cycle, so that the main AO port 11 and the backup AO port 12 simultaneously receive the analog quantity sent by the external load 30. In some embodiments of the present application, the preset cycle is 1000ms.

[0064] The controller 300 compares whether the analog quantities on the main AO port 11 and the standby AO port 12 are consistent. If the error between the analog quantities on the main AO port 11 and the standby AO port 12 exceeds a preset threshold, it means that at least one of the main AO port 11 and the standby AO port 12 is abnormal, so it is necessary to perform self-detection on the AO port 10, that is, enter the self-detection mode. If the error between the analog quantities on the main AO port 11 and the standby AO port 12 does not exceed the preset threshold, it means that the main AO port 11 and the standby AO port 12 are currently functioning normally. At this time, the controller 300 sends a feedback signal to the multiplexer to confirm that the function is normal, so as to drive the multiplexer to disconnect the third relay switch K3 and keep the second relay switch K2 closed.

[0065] Therefore, the embodiment of the present application performs redundant design for the AO port, and through the comparison mechanism between the redundant ports, possible abnormalities or errors in the main AO port can be detected. Once the detection result shows that the signal difference between the main AO port and the backup AO port exceeds the allowable range, it is automatically determined whether the analog output board enters the self-detection mode based on the comparison result to further calibrate the accuracy and stability of the port. On the one hand, it can enhance the reliability and fault tolerance of the AO port, and on the other hand, it can realize the function of entering the self-detection mode, reduce human intervention and detection time, and improve the self-detection efficiency and reliability of the analog output board.

[0066] In the embodiment of the present application, the self-detection calibration circuit 20 further includes a signal calibration unit 400 , wherein the signal calibration unit 400 is configured to determine a calibration coefficient according to a ratio of the first detection signal to the first sampling signal when an abnormality occurs in the AO port 10 .

[0067] Furthermore, the signal calibration unit 400 is further configured to send the calibration coefficient to the controller 300 and drive the signal calibration program of the controller 300 to calibrate the analog quantity on the AO port 10 based on the calibration coefficient.

[0068] For example, assuming that the current analog quantity corresponding to the first detection signal received through the self-detection AI port is 4mA, and the current analog quantity corresponding to the first sampling signal collected on the AO port is 3mA, the calibration coefficient k is determined to be 4 / 3. In the subsequent analog input process, the analog quantity sent by the AO port is always multiplied by the calibration coefficient k through the signal calibration program of the controller 300, that is, the AO port is soft-compensated through the signal calibration program of the controller 300 until the calibration coefficient is updated again in the next self-detection process.

[0069] Therefore, the embodiment of the present application realizes automatic calibration of the AO port 10 through the signal calibration unit 400. If an abnormality occurs in the AO port 10, the signal calibration unit 400 will determine the calibration coefficient k according to the ratio of the first detection signal to the first sampling signal to reflect the deviation between the signal output through the AO port 10 and the actual output signal, thereby providing a basis for the calibration of the AO port 10 and greatly improving the stability of the AO port 10.

[0070] Accordingly, an embodiment of the present application provides an analog output board, comprising a plurality of independent AO signal input units 30 and a self-detection calibration circuit 20, wherein the input end of each AO signal input unit 30 is configured as a group of AO ports 10, and the self-detection calibration circuit 20 configures the circuit corresponding to the AO port 10.

[0071] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0072] In an embodiment of the present application, the above-mentioned analog output board also includes a health management unit, which includes a voltage detection circuit, a current detection circuit, a temperature detection circuit and a co-controller. The voltage detection circuit is configured to collect the working voltage of the analog output board, the current detection circuit is configured to collect the working current of the analog output board, the temperature detection circuit is configured to detect the working temperature of the analog output board, and the co-controller is configured to receive the working voltage, working current and working temperature, and to alarm when the working voltage, working current and working temperature exceed the preset rated range.

[0073] In some embodiments of the present application, the model of the above-mentioned co-controller is QJ32F103CBT6, and the processor provides 128KB internal FLASH, 20KB internal SRAM, and also provides 3 UART interfaces, 2 I2C interfaces, 2 SPI interfaces, 37 GPIO interfaces, and 2 12-bit precision 2MSPS ADC first controllers with a total of 10 channels, and also provides 1 USB interface and 1 CAN interface, etc., to meet the functional requirements of the health management unit. In addition, the co-controller communicates with the controller 300 through the UART bus, which is used to cut off the connection between the AO port 10 and the external load through the controller 300 when an alarm occurs in the co-controller.

[0074] Specifically, the voltage detection circuit collects data through the 12-bit precision ADC built into the co-controller. The voltage detection circuit can collect up to 10 voltages at the same time. The built-in 12-bit ADC with an accuracy of 1% is used to measure each input and compare the result with the overvoltage threshold, undervoltage threshold, and the warning threshold configured as undervoltage or overvoltage. When the measured voltage exceeds the set threshold, a fault alarm signal is issued, which can be detected by I 2C bus interface communicates with the host computer or management chip to realize multiple modes of alarm. The ADC integrated in the co-controller collects voltage in the range of 0-3.6V, so the voltage exceeding 3.6V needs to be divided, and then the real voltage value is restored on the voltage value through the internal calculation formula. The current detection circuit first converts the current to voltage through the op amp, then adjusts the output impedance through voltage following, and finally enters the MCU for AD acquisition. The temperature detection circuit uses the temperature sensor model NST175H-QMSR, which is an integrated digital temperature sensor with a 12-bit analog-to-digital converter that can be powered by a 2.7V~5.5V power supply. It can read the temperature with a resolution of 0.0625℃ and can be rated to operate in the temperature range of -55℃ to +125℃. The digital output with a two-wire I2C interface can communicate with the host computer or a dedicated management chip through the I2C bus to realize real-time monitoring and management functions.

[0075] The embodiment of the present application realizes the detection of voltage, current and temperature of the analog output board through the voltage detection circuit, current detection circuit and temperature detection circuit in the health management unit, and alarms the abnormal detection results through the auxiliary controller, which helps to ensure the normal operation of the analog output board and improve the reliability and stability of the analog output board.

[0076] The analog output card proposed in the embodiment of the present application detects the analog receiving function of the AI ​​port through the above-mentioned self-detection calibration circuit 20, so as to timely discover whether the AI ​​port has any abnormality. Therefore, the embodiment of the present application forms a self-detection feedback mechanism inside the analog output card by integrating the self-detection calibration circuit in the analog output card, which can effectively avoid the problem of difficulty in AI port detection caused by interference from external environmental factors in harsh environments, and effectively suppresses the interference of external environmental changes on AI port detection, ensuring the accuracy and real-time nature of the detection results, and can also reduce the time cost and labor cost of detection in harsh environments, greatly improving the detectability and reliability of the AI ​​port.

[0077] Although the embodiments of the present application are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

[0078] For the convenience of description, the above device is described in various units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0079] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0080] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0081] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

[0082] Although the embodiments of the present application have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A self-detection calibration circuit for an analog output card, characterized in that: The analog output board is provided with a plurality of mutually independent AO ports, and the self-detection calibration circuit comprises: A signal collection unit, wherein the signal collection unit is provided with a self-detection AI port, and the self-detection AI port is configured to collect a first detection signal output by the AO port to generate a first sampling signal, wherein the first detection signal is provided by the AO signal output unit of the analog output board; a channel selection unit, the channel selection unit being configured to connect the AO port and the self-detection AI port to send the first sampling signal to the AO port; A controller is configured to control the AO signal output unit to generate the first detection signal, compare the first detection signal with the first sampling signal, and detect whether an abnormality occurs in the AO port according to the comparison result.

2. The self-detection calibration circuit according to claim 1, characterized in that: The signal recovery unit comprises: A first amplifying circuit, wherein the first amplifying circuit is configured to amplify the analog quantity on the AO port, wherein the input end of the first amplifying circuit is configured as the self-detection AI port; The analog-to-digital conversion circuit is configured to perform analog-to-digital conversion on the analog quantity after differential amplification by the first amplifier circuit to obtain the first sampling signal, and send the first sampling signal to the controller through the I2C bus.

3. The self-detection calibration circuit according to claim 2, characterized in that: The first amplifying circuit comprises: a first amplifier, wherein a positive input terminal of the first amplifier is connected to an AI+ port in the self-detection AI port via a first protection circuit, and a negative input terminal of the first amplifier is connected to an output terminal of the first amplifier; a second amplifier, wherein a positive input terminal of the second amplifier is connected to an AI-port in the self-detection AI port via a second protection circuit, and a negative input terminal of the second amplifier is connected to an output terminal of the second amplifier; A third amplifier, wherein the positive input terminal of the third amplifier is connected to the output terminal of the second amplifier, the negative input terminal of the third amplifier is connected to the output terminal of the first amplifier, and the output terminal of the third amplifier is connected to the input terminal of the analog-to-digital conversion circuit through a first current limiting circuit.

4. The self-detection calibration circuit according to claim 1, characterized in that: The channel selection unit is configured to cut off the connection between the AO port and the external load and connect the AO port to the self-detection AI port when the analog output board is in the self-detection mode.

5. The self-detection calibration circuit according to claim 4, characterized in that: The channel selection unit includes a multiplexer, wherein an input end of the multiplexer is connected to the self-detection AI port, a first output end of the multiplexer is connected to a first relay switch between the AO port and the self-detection AI port, and a second output end of the multiplexer is connected to the AO port and a second relay switch of the external load.

6. The self-detection calibration circuit according to claim 4, characterized in that: The AO port adopts a redundant design, wherein the AO port includes a primary AO port and a backup AO port; The controller is also configured to, when the main AO port is connected to the external load, drive the channel selection unit to simultaneously connect the main AO port and the backup AO port to the external load based on a preset cycle, compare the analog quantities on the main AO port and the backup AO port, and determine that the analog output board enters the self-detection mode based on the comparison result.

7. The self-detection calibration circuit according to claim 1, characterized in that: The self-detection calibration circuit further includes a signal calibration unit, which is configured to determine a calibration coefficient according to a ratio of the first detection signal to the first sampling signal when an abnormality occurs in the AO port.

8. The self-detection calibration circuit according to claim 7, characterized in that: The signal calibration unit is further configured to send the calibration coefficient to the controller and drive a signal calibration program of the controller to calibrate the analog quantity on the AO port based on the calibration coefficient.

9. An analog output board, characterized in that: The analog output board comprises: A plurality of mutually independent AO signal output units, wherein the output end of each of the AO signal output units is configured as an AO port; According to any one of claims 1 to 8, the self-detection calibration circuit is configured corresponding to the AO port.

10. The analog output board according to claim 9, characterized in that: The AO signal output unit adopts a redundant design, and the AO signal input unit includes a main AO signal input unit and a standby AO signal input unit.

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