Multi-channel electromagnetic valve fault detection device and method

Abstract

The embodiment of the invention provides a multi-channel electromagnetic valve fault detection device and method, and belongs to the technical field of relay driving and DO isolation output. The detection device comprises a driver which is connected to positive and negative ends of control signals of each channel and is used for driving an electromagnetic valve of each channel; the control signal detection unit is connected in parallel with the input side of the driver and is used for detecting whether a control signal exists or not; the current isolation sampling unit is arranged on the output side of the driver in a non-contact manner and is used for collecting the real-time current value of the electromagnetic valve of each channel; and the control unit is used for triggering the current isolation sampling unit to collect the real-time current value when the control signal detection unit detects the control signal, and is also used for receiving the real-time current value, judging whether the channel loop is abnormal or not, and then sending out an alarm signal. The system is simple in structure, low in cost, high in integration level, high in reliability, wide in application range and rich in detection and diagnosis functions.

Description

Technical Field

[0001] The present invention relates to the technical field of relay drive and DO isolation output, and in particular to a multi-channel solenoid valve fault detection device and method. Background Art

[0002] At present, solenoid valves are widely used in process industries such as petrochemicals, and are used in extremely important links. Solenoid valves can be divided into two categories according to their application scenarios: one is used in interlocking solenoid valves. When industrial devices such as petrochemicals are operating normally, the solenoid valve is always energized. At this time, the current in the solenoid valve circuit is a steady-state value. Only when the device is abnormal, the control system issues a power-off command, the solenoid valve loses power, and the solenoid valve circuit current becomes 0mA. At this time, the solenoid valve drives the control valve installed on the process to close or open, so that the device is in a safe state. Since the device rarely has abnormal conditions, the solenoid valve used in interlocking solenoid valves is always energized most of the time, so the daily equipment monitoring personnel focus on the "health" state of the solenoid valve when it is energized for a long time. Another application scenario is the programmable valve scenario, where the solenoid valve is energized or de-energized according to the steps specified by the program (for example, the solenoid valve is energized once in each cycle of 30 minutes, maintained for 5 minutes, and then de-energized for 25 minutes). In this type of working condition, the equipment personnel focus on whether the solenoid valve is successfully actuated each time from de-energization to energization. If there is a slight jam during the action process, intervention measures can be taken in advance.

[0003] At present, control systems such as Safety Instrumented System (SIS) and Distributed Control System (DCS) used for industrial control generally need to be equipped with relays to drive field solenoid valves. Relays play the role of signal isolation and power amplification. There are two installation forms of relays: one is an independent relay, that is, each relay is equipped with an independent terminal base, and the other is a relay output module composed of multiple relays.

[0004] After the DO output circuit of the control system is isolated by relays, the DO action command issued by the control system may be inconsistent with the actual contact action signal after the relay is isolated due to a fault in the relay itself or a line fault, that is, the actuator of the DO action command does not act. To solve the above problems, most of the existing relay DO isolation circuits use the method of reading back the state of the auxiliary contacts of the relay to determine whether the relay is normal. Usually, the relay has multiple pairs of contacts, one pair is unloaded, and the other pair of contacts can be read back to the control system as a DI point. When the relay is enabled, multiple pairs of contacts act at the same time, indicating that the relay performance is normal. However, the state of the auxiliary contact cannot fully represent the state of the pair of contacts that drive the load, so this method is not perfect for detecting the real signal after the relay.

[0005] The Chinese patent "Relay Diagnosis Method and System", application number CN201610943230.0, authorization announcement number CN107991603B, discloses a relay diagnosis method and system, the diagnosis method includes: sending a control signal to the relay, the types of control signals include enable signal and disable signal; sending a detection signal on one side of the relay, receiving a feedback signal on the other side of the relay; comparing the detection signal and the feedback signal to obtain a comparison result, when the comparison result matches the control signal, the relay is judged to be normal, otherwise the relay is judged to be faulty. This patent injects a detection signal at the input of the relay contact and reads back the signal at the output contact of the relay to determine whether the relay is working properly. This method only detects the on and off of the relay itself, and does not pay attention to the load condition. It cannot detect whether the load is good, and the detection circuit of this patent cannot adapt to AC applications.

[0006] The Chinese patent "Feedback circuit of flushing solenoid valve of water purifier" has application number CN201420322946.5 and authorization announcement number CN204044541U, which discloses a feedback circuit of flushing solenoid valve of water purifier, including relay, feedback circuit of flushing solenoid valve and solenoid valve control circuit. One end of the power input end of flushing solenoid valve is connected to 24V power supply, and the other end is connected to contact end 2 of relay. Contact end 5 of relay is connected to 24V power supply. Contact end 6 corresponding to contact end 5 is divided into two paths. The first path is connected to ground through resistor R2, and the second path is connected to ground through resistor R1 and capacitor C1. The node of resistor R1 and capacitor C1 is connected to 5V power supply through diode D1. The node of resistor R1 and capacitor C1 is the feedback signal end of flushing solenoid valve, which is connected to the feedback input end of flushing solenoid valve of microprocessor. The patent identifies whether the relay is operating normally by detecting the voltage of resistor R2 added to the output circuit. The detection circuit of this method is not isolated and cannot adapt to AC application.

[0007] The Chinese patent "A multi-channel electromagnetic valve current acquisition device and acquisition method", application number CN200810133072.8, authorization announcement number CN101324642B, discloses a multi-channel electromagnetic valve current acquisition device, which is composed of a single-chip microcomputer A / D processing module (1), a CAN communication module (2), a computer communication module (3), an amplifier circuit module (4), a sampling resistor module (5), and an external circuit module (6). The sampling resistor is a precision resistor, which is connected in series in the electromagnetic valve circuit to be measured, and its two ends are respectively connected to the first-stage operational amplifier. The first-stage operational amplifier extracts the tiny voltage drop at both ends of the sampling resistor, and sends it to the second-stage operational amplifier after adjusting the amplification factor through the adjustment resistor. The filter resistor and the filter capacitor filter the amplified signal and send the result to the single-chip microcomputer A / D processing module. Then the processed signal is sent to the host computer through the CAN communication module. This patent uses a precision resistor R in series in the load electromagnetic valve circuit. SEN By measuring the voltage change of the precision resistor, the current value of the solenoid valve circuit is finally obtained. This method is not associated with the relay state, and the circuit for detecting the load current is not isolated from the load circuit.

[0008] The Chinese patent "System and method for online diagnosis of interlock solenoid valve faults", application number CN202111068062.2, authorization announcement number CN115792484A, discloses a system and method for online diagnosis of interlock solenoid valve faults, belonging to the field of oil refining and chemical technology. The system for online diagnosis of interlock solenoid valve faults includes: a mutual inductance current transmitter, one of the wires of the interlock solenoid valve circuit passes through the small hole in the middle of the mutual inductance current transmitter, which is used to convert the loop current of the interlock solenoid valve into a corresponding setting signal; and a signal acquisition monitoring system, which is electrically connected to the mutual inductance current transmitter, and is used to receive the setting signal output by the mutual inductance current transmitter, and diagnose whether the interlock solenoid valve has a fault according to the setting signal. This patent inserts a mutual inductance current transmitter in series into the existing solenoid valve drive circuit to obtain the current value, and outputs it to the signal acquisition and monitoring system for monitoring, so as to judge the fault condition of the solenoid valve based on the current value. The integration of this method is not high, and each channel requires a transmitter, which requires a large installation space. In addition, it is limited by the sensor and communication method. This technology only supports steady-state current detection and cannot detect the dynamic current at the moment of solenoid valve startup.

[0009] The inventors of this application discovered during the process of implementing the present invention that the above-mentioned scheme of the prior art has the following defects: lack of detection or incomplete detection; the detection loop and the execution loop are not isolated, and the reliability is poor; the application objects are fixed and the adaptability is narrow; and, in addition, the relay output boards of various brands of control systems on the market currently do not support load solenoid valve current detection, and the control system cannot know whether the load circuit is normal after the control system command is issued. Summary of the invention

[0010] The purpose of the embodiment of the present invention is to provide a device, which is based on the relay drive module of the control system. In order to avoid the newly added current detection function affecting the original solenoid valve circuit, a highly integrated isolation current sensing technology is introduced, the switch trigger logic is designed to realize efficient dynamic current sampling, and an integrated design is performed to realize full-circuit effective detection of multi-channel circuits. Specifically, when the control signal detection unit connected in parallel with the input side of each channel driver detects the control signal issued by the control system, the control unit triggers the current isolation sampling unit to collect the real-time current value of the solenoid valve in different application scenarios according to different sampling rates. The control unit receives the real-time current signal output by the current isolation sampling unit of each channel, and then determines whether the circuit of each channel is abnormal and sends an alarm signal. The device also uploads the real-time current signal and alarm signal output by the control unit to the control system through the output unit, thereby realizing full-circuit state monitoring of whether the command issued by the control system is activated at the load end. The device has a simple structure, low cost, high integration, high reliability, wide adaptability, and rich detection and diagnosis functions.

[0011] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a multi-channel solenoid valve fault detection device, which includes: a driver, wherein the input end of the driver is connected to the positive and negative ends of the control signal of each channel, and is used to drive the solenoid valve of each channel; a control signal detection unit, which is connected in parallel with the input side of the driver of each channel, and is used to detect the presence or absence of the control signal; a current isolation sampling unit, which is placed on the output side of the driver of each channel in a non-contact manner, and is used to collect the real-time current value of the solenoid valve of each channel on the field side; and a control unit, which is used to trigger the current isolation sampling unit to collect the real-time current value of the solenoid valve through different sampling methods when the control signal detection unit detects the control signal. The control unit is also used to receive the real-time current signal output by the current isolation sampling unit, and determine whether the circuit of the channel corresponding to the current isolation sampling unit is abnormal, and then send out an alarm signal, wherein, for the channel using the interlocking solenoid valve, the current isolation sampling unit of the channel collects the real-time current value of the solenoid valve through a slow sampling method. The real-time current value is compared with the steady-state current value when the interlock solenoid valve is working normally. When the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal; and for the channel of the application programmable solenoid valve, the current isolation sampling unit of the channel collects the real-time current value through high-speed sampling. The control unit draws a real-time current dynamic curve according to the collected real-time current value, and determines the judgment interval (T0-T1) of the real-time current dynamic curve. Compared with the standard current dynamic curve, when the difference between the peak current maximum value and the valley current minimum value of the real-time current dynamic curve in the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 is the corresponding moment when the real-time current value reaches a preset percentage value of the steady-state current value.

[0012] Optionally, the peak current maximum value and the valley current minimum value are determined in the following manner: for the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the point whose absolute value of the slope value is closest to 0 is determined as the peak point and valley point on the real-time current dynamic curve; the highest peak point among the peak points of the real-time current dynamic curve is determined, and the peak current corresponding to the highest peak point is taken as the peak current maximum value; and the lowest valley point among the valley points of the real-time current dynamic curve is determined, and the valley current corresponding to the lowest valley point is taken as the valley current minimum value.

[0013] Optionally, for a channel using a programmable solenoid valve, after the real-time current value collected by the current isolation sampling unit of the channel reaches the steady-state current value, the current isolation sampling unit collects the real-time current value using a slow sampling method. Compared with the steady-state current value, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, the control unit determines that an abnormality has occurred in the circuit of the channel and issues an alarm signal.

[0014] Optionally, the driver, the control signal detection unit, the current isolation sampling unit and the control unit are all integrated and mounted on a terminal board.

[0015] Optionally, the current isolation sampling unit uses a sensor chip based on tunnel magnetoresistance (TMR) effect to achieve isolation and acquisition of the real-time current value of the solenoid valve.

[0016] Optionally, the device also includes: an output unit, used to receive the real-time current signal and alarm signal output by the control unit, and communicate them to the control system, wherein the alarm signal is a switch signal, and the output unit is also used to communicate the real-time current signal to the control system; and a control system, used to issue a control signal, and also used to receive the real-time current signal and switch alarm signal output by the output unit.

[0017] Optionally, the control system is also used to record the real-time current signal, and draw a standard current dynamic curve or determine the steady-state current value based on the real-time current signal when the solenoid valve is working normally in the historical records, and then determine the alarm threshold based on the steady-state current value. The control system is also used to communicate the steady-state current value and the alarm threshold or the standard current dynamic curve to the control unit through the output unit.

[0018] On the other hand, the present invention provides a fault detection method for a multi-channel solenoid valve, the method comprising: detecting the presence or absence of a control signal on the driver input side of each channel, wherein the input end of the driver is connected to the positive and negative ends of the control signal of each channel, for driving the solenoid valve of each channel; and when there is a control signal on the driver input side, triggering the acquisition of a real-time current signal of the solenoid valve in the channel corresponding to the driver, and determining whether an abnormality occurs in the circuit of the channel corresponding to the driver, and then issuing an alarm signal, wherein, for a channel using an interlocking solenoid valve, the real-time current value is acquired by slow sampling, and compared with the steady-state current value when the interlocking solenoid valve is working normally, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, The control unit determines that an abnormality occurs in the circuit of the channel and sends out an alarm signal; and for the channel using the programmable solenoid valve, the real-time current value is collected by high-speed sampling, a real-time current dynamic curve is drawn according to the collected real-time current value, and a judgment interval (T0-T1) of the real-time current dynamic curve is determined. Compared with the standard current dynamic curve, when the difference between the peak current maximum value and the valley current minimum value of the real-time current dynamic curve within the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, it is determined that an abnormality occurs in the circuit of the channel and an alarm signal is sent, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 corresponds to the moment when the real-time current value reaches a preset percentage value of the steady-state current value.

[0019] Optionally, the peak current maximum value and the valley current minimum value are determined in the following manner: for the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the point whose absolute value of the slope value is closest to 0 is determined as the peak point and valley point on the real-time current dynamic curve; the highest peak point among the peak points of the real-time current dynamic curve is determined, and the peak current corresponding to the highest peak point is taken as the peak current maximum value; and the lowest valley point among the valley points of the real-time current dynamic curve is determined, and the valley current corresponding to the lowest valley point is taken as the valley current minimum value.

[0020] Optionally, for the channel of the application programmable solenoid valve, after the collected real-time current value reaches the steady-state current value, the real-time current value is collected by slow sampling. Compared with the steady-state current value, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, it is judged that the circuit of the channel is abnormal and an alarm signal is issued.

[0021] On the other hand, the present invention provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute any one of the above-mentioned fault detection methods for a multi-channel solenoid valve of the present application.

[0022] Through the above technical scheme, the present invention utilizes that when the control signal detection unit connected in parallel with the input side of each channel driver detects the control signal issued by the control system, the control unit triggers the current isolation sampling unit to collect the real-time current value of the solenoid valve in different application scenarios according to different sampling rates. The control unit receives the real-time current signal output by the current isolation sampling unit of each channel, and then determines whether the circuit of each channel is abnormal and issues an alarm signal. The device also uploads the real-time current signal and alarm signal output by the control unit to the control system through the output unit, thereby realizing full-circuit status monitoring of whether the command issued by the control system is actuated to the load end. Industrial control systems are often large-scale and have many DO channels. The present invention can realize closed-loop detection of the solenoid valve control loop, and the integration does not increase additional wiring, which is convenient for large-scale installation and deployment of the control system, thereby improving system reliability and maintainability; the present invention does not require complex chips such as field programmable gate arrays (Field-Programmable Gate Array, FPGA), and only requires a simple microcontroller (Microcontroller Unit, MCU) to realize steady-state current detection and dynamic current detection of multiple solenoid valves, thereby reducing costs; the present invention optimizes the current sampling rate and reduces the hardware resource requirements for sampling data; the present invention also supports the simultaneous access of loads with AC and DC power sources, has a wide range of adaptability, provides multiple monitoring parameters, and has more comprehensive load state identification and fault diagnosis functions.

[0023] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0025] Figure 1 This is a circuit diagram of the existing relay DO isolation provided by an embodiment of the present invention.

[0026] Figure 2 It is a circuit diagram of a multi-channel solenoid valve fault detection device provided by an embodiment of the present invention.

[0027] Figure 3 It is a circuit diagram of a single-channel solenoid valve fault detection device provided in an embodiment of the present invention.

[0028] Figure 4 This is a physical picture of the current isolation acquisition sensor TMR chip provided in an embodiment of the present invention.

[0029] Figure 5It is a structural diagram of a push-pull Wheatstone full bridge of a TMR element provided in an embodiment of the present invention.

[0030] Figure 6 This is a graph showing a change in current sampling rate of a programmable solenoid valve provided by an embodiment of the present invention.

[0031] Figure 7 1 is a diagram of the steps of an algorithm for determining the maximum peak and valley points of a current dynamic curve of a programmable solenoid valve provided by an embodiment of the present invention.

[0032] Figure 8 This is the second step of the algorithm for determining the peak and valley maximum values ​​of the current dynamic curve of the programmable solenoid valve provided by the embodiment of the present invention.

[0033] Fig. 9 It is a diagram of the third step of an algorithm for determining the maximum peak and valley points of a current dynamic curve of a programmable solenoid valve provided by an embodiment of the present invention.

[0034] Fig.10 4 is a diagram of the steps of an algorithm for determining the maximum peak and valley points of a current dynamic curve of a programmable solenoid valve provided by an embodiment of the present invention.

[0035] Fig.11 It is an alarm interval diagram of a standard current dynamic curve provided by an embodiment of the present invention.

[0036] Fig.12 It is a flow chart of a fault detection method for a multi-channel solenoid valve provided in an embodiment of the present invention.

[0037] Fig.13 It is a flow chart of a method for determining a maximum value of a peak current and a minimum value of a valley current provided by an embodiment of the present invention.

[0038] Description of Reference Numerals

[0039] 1 Driver input terminal 2 Driver input terminal

[0040] 3 Driver output terminal 4 Driver output terminal

[0041] 5 Driver output terminal DETAILED DESCRIPTION

[0042] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0043] Figure 1 is a conventional relay DO isolation circuit diagram provided by an embodiment of the present invention, Figure 2 is a circuit diagram of a multi-channel solenoid valve fault detection device provided by an embodiment of the present invention, Figure 3is a circuit diagram of a single-channel solenoid valve fault detection device provided by an embodiment of the present invention, see Figure 1 , Figure 2 and Figure 3 As shown, the multi-channel solenoid valve fault detection device includes: a driver, the input end of the driver is connected to the positive and negative ends of the control signal of each channel, and is used to drive the solenoid valve of each channel; a control signal detection unit, which is connected in parallel with the driver input side of each channel, and is used to detect the presence or absence of the control signal; a current isolation sampling unit, which is placed on the output side of the driver of each channel in a non-contact manner, and is used to collect the real-time current value of the solenoid valve of each channel on the field side; and a control unit, which is used to trigger the current isolation sampling unit to collect the real-time current value of the solenoid valve through different sampling methods when the control signal detection unit detects the control signal. The control unit is also used to receive the real-time current signal output by the current isolation sampling unit, and determine whether the circuit of the channel corresponding to the current isolation sampling unit is abnormal, and then send out an alarm signal.

[0044] Optional, such as Figure 1 As shown, the driver is preferably a relay, and the "HF41F / 24-ZST (414)" shown in the figure is the relay model used in the embodiment of the present invention. Figure 2 As shown, the multi-channel solenoid valve fault detection device provided by the embodiment of the present invention is based on a relay drive module, including multiple relay channels, a control unit and an output unit, see Figure 2 and Figure 3 As shown, each relay channel is equipped with a control signal detection unit and a current isolation sampling unit. The control unit, output unit, relays of each channel, control signal detection unit and current isolation sampling unit are integrated in a relay drive module.

[0045] Optional, see Figure 2 and Figure 3 As shown, the control signal detection unit of the embodiment of the present invention is connected to the positive and negative ends of the control signal and is connected in parallel with the input side of the relay. The control signal detection unit is used to detect the opening and closing of the control signal. The control signal undergoes signal isolation before being connected to the control signal detection unit. Optionally, the isolation transmission mode includes optical coupling, magnetic isolation, capacitive isolation or digital isolator.

[0046] Optionally, the control unit of an embodiment of the present invention mainly includes an MCU and an analog-to-digital converter (A / D). The control unit is used to trigger the current isolation sampling unit to collect the real-time current value of the solenoid valve when the control signal detection unit detects the control signal, and receive the real-time current signal output by the current isolation sampling unit, generate a standardized real-time current value and action instantaneous current capture data through calculation processing, and determine whether the circuit of the channel corresponding to the current isolation sampling unit is abnormal, and then issue an alarm signal.

[0047] Optionally, the multi-channel solenoid valve fault detection device provided in the embodiment of the present invention further includes: an output unit, which is used to receive the real-time current signal and alarm signal output by the control unit, and output it to the control system, wherein the alarm signal is a switch signal, and the output unit is also used to communicate the real-time current signal to the control system; and a control system, which is used to send a control signal and is also used to receive the real-time current signal and switch alarm signal output by the output unit. Optionally, the communication method of the output unit provided in the embodiment of the present invention includes RS485, CAN, etc., and the communication interaction of control unit data and status information is realized through the communication method. The control system provided in the embodiment of the present invention can be selected as a SIS, DCS or PLC system.

[0048] Optional, Figure 4 : is a physical picture of the current isolation acquisition sensor TMR chip provided by the embodiment of the present invention, such as Figure 4 As shown, the current isolation sampling unit of the embodiment of the present invention adopts a TMR current sensor chip to obtain the real-time current value of the field-side solenoid valve. TMR current detection technology is based on the quantum effect of the TMR element. By applying external magnetic fields of different strengths, the magnetic moment direction of adjacent magnetic layers is changed to achieve the transition of the resistance of the TMR element from a high resistance state to a low resistance state. The TMR effect can be theoretically explained by the tunnel Hamiltonian method and the quantum mechanics tunneling method. The maximum magnetoresistance change rate of the tunnel magnetoresistance effect at room temperature can reach 600%. Figure 5 : is a diagram of a push-pull Wheatstone full bridge structure of a TMR element provided in an embodiment of the present invention, such as Figure 5 As shown in the figure, the TMR element is composed of four tunnel magnetoresistors R1, R2, R3 and R4 with the same resistance value, and these four tunnel magnetoresistors are respectively located on the four bridge arms of the TMR element. When the TMR element is placed in the magnetic field generated by the wire, so that the magnetic sensitivity direction is parallel to the magnetic field direction, the resistance value of the TMR element will change accordingly, and the change in resistance value is finally converted into an output voltage signal generated by the differential amplifier circuit. The voltage signal has a certain relationship with the magnitude of the current in the wire, so the purpose of current measurement can be achieved by detecting the output voltage. Figure 5The VCC shown in the figure is the power supply voltage for providing electric energy, and the magnetic sensitivity direction of the TMR resistor is shown by the arrow. V+ and V- are the output voltages of the half-bridge formed by R1 and R2, and R3 and R4, respectively, which can be used as a full-bridge output, and then the output voltage is generated by the differential amplifier circuit. The formula is as follows:

[0049] v out =k(V+-V-) (1)

[0050] Where: k is the differential amplification factor. After applying a DC excitation voltage to the resistance bridge, the output of the resistance bridge is linearly related to the magnetic field actually measured by the sensor.

[0051] Optionally, the highly integrated single-chip TMR current sensor chip used in the embodiment of the present invention has the following characteristics: high measurement accuracy, good anti-interference ability, high isolation voltage resistance, signal bandwidth higher than 2MHz, and can also obtain the current dynamic change characteristics of the solenoid valve coil. The sensor monitoring range can be developed to 0-300mA DC.

[0052] Optionally, the control signal emitted by the DCS system provided in the embodiment of the present invention is a switch signal with a DO instruction. The trigger signal for the MCU control unit to trigger the TMR to collect the real-time current value of the load is derived from the switch signal output of the DCS, SIS or PLC system. It has high reliability and is not affected by external factors, ensuring that each switch action can be effectively triggered.

[0053] Optionally, in an embodiment of the present invention, the control unit triggers the current isolation sampling unit to collect the real-time current value of the solenoid valve through different sampling methods, and the different sampling methods include high-speed sampling and slow sampling. Among them, for a channel using an interlocking solenoid valve, the current isolation sampling unit of the channel collects the real-time current value through a slow sampling method; and for a channel using a programmable solenoid valve, the current isolation sampling unit of the channel collects the real-time current value through a high-speed sampling method.

[0054] Optionally, for a channel using a program-controlled solenoid valve, the solenoid valve is energized or de-energized according to steps specified by the program, and the energization and de-energization alternate frequently. Figure 6 : is a graph showing the current sampling rate variation of a program-controlled solenoid valve provided by an embodiment of the present invention, such as Figure 6 As shown in the figure, the program-controlled solenoid valve is energized and de-energized once in a fixed cycle (for example, 30 minutes). It is energized once, maintained for 5 minutes, and then de-energized for 25 minutes. Equipment personnel often pay attention to the moment when the solenoid valve switches from the de-energized state to the energized state after the control system DO command is issued, and whether the solenoid valve completes the correct gas path switching, thereby driving the control valve to open or close. Figure 6As shown in the figure, when the solenoid valve is powered on from power off, the current in the solenoid valve circuit is a dynamic change curve, which lasts for about 300ms, but the repeatability is consistent each time it is switched, that is, the circuit current first rises, then falls, then rises again, and then reaches a steady-state current value. The preferred steady-state current value in the embodiment of the present invention is 140mA. Figure 6 As shown, at the moment when the solenoid valve is powered on from power off, the TMR of the channel collects the action current at the moment of power on of the solenoid valve through high-speed sampling to obtain the real-time current value. After the real-time current value collected by the TMR reaches 140mA, the TMR collects the real-time current value through slow sampling until entering the next DO trigger cycle. Preferably, the high-speed sampling method provided in the embodiment of the present invention samples one data at an interval of 1ms, and the slow sampling method samples one data at an interval of 1s. In this way, the dynamic current detection method based on the action edge time window greatly reduces the hardware resource requirements for storage, transmission and data analysis of high-speed sampling data.

[0055] Optionally, for the channel using interlock solenoid valve, the interlock solenoid valve will only operate when the device is abnormal, but most interlock solenoid valves will not operate (ie lose power) once in a maintenance cycle of the device (usually 4 years). Figure 1 As shown, during the maintenance cycle once every four years, the DO control signal received by the relay from the control system is always a high-level "1" signal, the coil of relay K3 is always energized, the relay contacts 4 and 5 are always closed, and the load solenoid valve is always energized. In this case, the equipment inspection personnel are concerned about whether the solenoid valve circuit has defects such as line damage, water ingress to the solenoid valve coil, and insulation degradation of the solenoid valve coil. These defects will cause abnormal loop current. Whether the solenoid valve is "healthy" can be understood by detecting whether the loop current is constant. The judgment mechanism is: when the difference between the real-time current value of the interlocking solenoid valve of the channel and its steady-state current value during normal operation exceeds the alarm threshold, the control unit determines that the loop of the channel is abnormal and sends an alarm signal. Optionally, the steady-state current value of the interlocking solenoid valve in the embodiment of the present invention is preferably 140mA during normal operation, and the preferred alarm threshold is ±5mA, that is, when the real-time current value of the interlocking solenoid valve is greater than 145mA or less than 135mA, it is judged that there is a problem in the channel loop where the load solenoid valve is located, and then the control unit sends an alarm signal.

[0056] Optionally, for the channel using programmable solenoid valve, the equipment personnel of this working condition focus on whether the solenoid valve is successfully operated each time when the programmable solenoid valve is powered on from power off. If there is a slight jam in the action process, intervention measures can be taken in advance. The mechanism for determining whether the solenoid valve is faulty is: TMR collects the dynamic current at each switch, and the control unit draws a real-time current dynamic curve based on the real-time current value collected, and determines the judgment interval (T0-T1) of the real-time current dynamic curve. Compared with the standard current dynamic curve, when the difference between the peak current maximum value and the valley current minimum value of the real-time current dynamic curve in the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 corresponds to the moment when the real-time current value reaches the preset percentage value of the steady-state current value.

[0057] Specifically, Figure 7-10 The figures shown are respectively steps one to four of the algorithm for determining the peak and valley points of the programmable solenoid valve current dynamic curve provided by an embodiment of the present invention. Optionally, for the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the point whose absolute value of the slope value is closest to 0 is determined as the peak point and valley point on the real-time current dynamic curve; the highest peak point among the peak points of the real-time current dynamic curve is determined, and the peak point current corresponding to the highest peak point is taken as the maximum peak current value; and the lowest valley point among the valley points of the real-time current dynamic curve is determined, and the valley point current corresponding to the lowest valley point is taken as the minimum valley current value.

[0058] Optional, such as Figure 7 The figure shows the step 1 of the peak-valley point maximum value determination algorithm - collecting current and drawing the current dynamic curve. Specifically, when the control signal detection unit detects the control signal sent by the DCS system, the MCU control unit triggers the TMR to collect the real-time current value of the program-controlled solenoid valve at a high speed every 1ms, and then draws the standard current dynamic curve and the real-time current dynamic curve. Among them, the MCU control unit can store real-time current data in a short period of time. Therefore, the standard current dynamic curve is drawn by the DCS system based on the historical normal working current data of the program-controlled solenoid valve uploaded by the MCU control unit, and the real-time current dynamic curve is drawn by the MCU control unit sampling the real-time current value collected by the TMR.

[0059] Optional, such as Figure 8The figure shows step 2 of the peak-valley point maximum value determination algorithm - determining the judgment interval (T0-T1) of the current dynamic curve. Optionally, T1 is the corresponding moment when the real-time current value reaches a preset percentage value of the steady-state current value. The embodiment of the present invention provides that the corresponding moment of triggering TMR to collect the real-time current value of the programmable solenoid valve is the starting point T0 of the judgment interval, and the end point T1 of the judgment interval is the corresponding moment when the current value reaches a preset percentage value of the steady-state current value. Among them, the preset percentage value of the steady-state current value is preferably 98% of the steady-state current value, and the steady-state current value is determined by taking the average value. Specifically, several data are taken as a group, and the average value is calculated. The average value of a group of data with the smallest total deviation from the average value is selected as the stable current value. For example, the average value is calculated for every 20 data, and the total deviation of these 20 data from the average value is calculated. The average value of the group of data with the smallest total deviation is the stable current value.

[0060] Optional, such as Fig. 9 The figure shows the step 3 of the peak-valley point determination algorithm - determining the peak and valley points of the current dynamic curve in the judgment interval T0-T1, such as Fig.10 The figure shows step 4 of the peak-valley point determination algorithm - determining the peak current maximum value and the valley current minimum value of the current dynamic curve in the judgment interval T0-T1. Optionally, in the embodiment of the present invention, N in the N sampling points is preferably 3, that is, in the judgment interval T0-T1, a slope value is calculated every 3 sampling points and its absolute value is taken, and the point closest to 0 in the absolute value is the peak point or valley point of the current dynamic curve. Among them, there may be more than one peak point or valley point between the interval T0-T1, that is, Fig. 9 The T2, T3, T4, and T5 shown are all the corresponding moments of the peak points or valley points of the current dynamic curve. Therefore, it is necessary to determine the highest peak point among the peak points and the lowest valley point among the valley points of the current dynamic curve, and take the peak current corresponding to the highest peak point as the maximum peak current value and the valley current corresponding to the lowest valley point as the minimum valley current value, that is, refer to Figure 9-10 As shown, T4 in T2-T5 is the time corresponding to the highest peak point, and T5 is the time corresponding to the lowest valley point, that is, the current corresponding to time T4 is the maximum value of the peak current, and the current corresponding to time T5 is the minimum value of the valley current.

[0061] Fig.11 The figure shows the alarm interval diagram of the standard current dynamic curve provided by the embodiment of the present invention, see Fig.10 and Fig.11As shown, the alarm interval of the standard current dynamic curve is obtained by amplifying the difference between the peak current maximum value corresponding to the standard current dynamic curve at the time T4 and the valley current minimum value corresponding to the time T5 by a preset multiple. In the embodiment of the present invention, the preset multiple is preferably 110%, that is, in the embodiment of the present invention, the alarm interval of the standard current dynamic curve is preferably the interval value of (peak current maximum value - valley current minimum value)*110% of the standard current dynamic curve.

[0062] Optional, see Figure 7-11 As shown, according to Figure 7-10 The algorithm steps 1 to 4 shown in the figure determine the standard current dynamic curve of the channel load program-controlled solenoid valve, the peak current maximum value and the valley current minimum value of the real-time current dynamic curve, and then Fig.11 The algorithm shown determines the alarm interval of the standard current dynamic curve. When the difference between the maximum current at the peak point and the minimum current at the valley point of the real-time current dynamic curve exceeds the alarm interval of the standard current dynamic curve, the MCU control unit determines that a fault has occurred in the channel load programmable solenoid valve and issues an alarm.

[0063] Fig.12 is a flow chart of a fault detection method for a multi-channel solenoid valve provided by an embodiment of the present invention, such as Fig.12 As shown, the method includes:

[0064] Step S100, detecting whether there is a control signal on the input side of the driver of each channel, wherein the input end of the driver is connected to the positive and negative ends of the control signal of each channel, for driving the solenoid valve of each channel;

[0065] Step S200, when there is a control signal on the input side of the driver, trigger the collection of the real-time current signal of the solenoid valve in the channel corresponding to the driver, and determine whether the circuit of the channel corresponding to the driver is abnormal, and then send out an alarm signal.

[0066] Wherein, step S200 further includes:

[0067] Step S210, for the channel using the interlock solenoid valve, the real-time current value is collected by slow sampling, and compared with the steady-state current value when the interlock solenoid valve is working normally, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal;

[0068] Step S220, for the channel of the application programmable solenoid valve, the real-time current value is collected by high-speed sampling, and a real-time current dynamic curve is drawn according to the collected real-time current value, and a judgment interval (T0-T1) of the real-time current dynamic curve is determined. Compared with the standard current dynamic curve, when the difference between the peak current maximum value and the valley current minimum value of the real-time current dynamic curve in the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, it is judged that the circuit of the channel is abnormal and an alarm signal is issued, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 is the corresponding moment when the real-time current value reaches a preset percentage value of the steady-state current value.

[0069] Optionally, the embodiments in step S100-step 200 and step S210-step S220 are similar to the above and will not be repeated here.

[0070] Optional, such as Fig.12 The maximum peak current and the minimum valley current in step S220 can be calculated based on the following example: Fig.13 The method for determining the maximum value of the peak current and the minimum value of the valley current provided by the embodiment of the present invention shown in FIG. 1 is determined by the flowchart of the method, the method comprising:

[0071] Step S221, for the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the point whose absolute value of the slope value is closest to 0 is determined as the peak point and the valley point on the real-time current dynamic curve;

[0072] Step S222, determining the highest peak point among the peak points of the real-time current dynamic curve, and taking the peak current corresponding to the highest peak point as the peak current maximum value;

[0073] Step S223, determining the lowest valley point among the valley points of the real-time current dynamic curve, and taking the valley point current corresponding to the lowest valley point as the minimum valley point current value.

[0074] Optionally, the embodiments in step S221 to step S223 are similar to those above and will not be repeated here.

[0075] 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.

[0076] The above are only embodiments of the present application and are 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 within the scope of the claims of the present application.

Claims

1. A multi-channel solenoid valve fault detection device, It is characterized in that The device includes: A driver, the input end of which is connected to the positive and negative ends of the control signal of each channel, and is used to drive the solenoid valve of each channel; A control signal detection unit, connected in parallel with the driver input side of each channel, for detecting the presence or absence of a control signal; A current isolation sampling unit is placed at the output side of the driver of each channel in a non-contact manner to collect the real-time current value of the solenoid valve of each channel on the field side; and A control unit is used to trigger the current isolation sampling unit to collect the real-time current value of the solenoid valve through different sampling methods when the control signal detection unit detects the control signal. The control unit is also used to receive the real-time current signal output by the current isolation sampling unit, and determine whether the circuit of the channel corresponding to the current isolation sampling unit is abnormal, and then send out an alarm signal, wherein, For a channel using an interlocking solenoid valve, the current isolation sampling unit of the channel collects the real-time current value by slow sampling, and compares the real-time current value with the steady-state current value when the interlocking solenoid valve is working normally. When the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, the control unit determines that an abnormality occurs in the circuit of the channel and issues an alarm signal; and For the channel of the application programmable solenoid valve, the current isolation sampling unit of the channel collects the real-time current value through high-speed sampling. The control unit draws a real-time current dynamic curve based on the collected real-time current value, and determines the judgment interval (T0-T1) of the real-time current dynamic curve. Compared with the standard current dynamic curve, when the difference between the peak current maximum value and the valley current minimum value of the real-time current dynamic curve in the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 corresponds to the moment when the real-time current value reaches a preset percentage value of the steady-state current value.

2. The device according to claim 1, It is characterized in that The peak current maximum value and the valley current minimum value are determined by: For the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the points whose absolute values ​​of the slope values ​​are closest to 0 are determined as the peak points and valley points on the real-time current dynamic curve; Determine the highest peak point among the peak points of the real-time current dynamic curve, and take the peak current corresponding to the highest peak point as the peak current maximum value; as well as The lowest valley point among the valley points of the real-time current dynamic curve is determined, and the valley point current corresponding to the lowest valley point is used as the valley point current minimum value.

3. The device according to claim 1, It is characterized in that For the channel of the application programmable solenoid valve, after the real-time current value collected by the current isolation sampling unit of the channel reaches the steady-state current value, the current isolation sampling unit adopts a slow sampling method to collect the real-time current value. Compared with the steady-state current value, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, the control unit determines that the circuit of the channel is abnormal and sends an alarm signal.

4. The device according to claim 1, It is characterized in that The driver, the control signal detection unit, the current isolation sampling unit and the control unit are all integrated and mounted on a terminal board.

5. The device according to any one of claims 1 to 4, It is characterized in that The current isolation sampling unit uses a sensor chip based on the tunnel magnetoresistance effect to isolate and collect the real-time current value of the solenoid valve.

6. The device according to claim 1, It is characterized in that The device also includes: an output unit, used to receive the real-time current signal and the alarm signal output by the control unit, and communicate them to the control system, wherein the alarm signal is a switch signal, and the output unit is also used to communicate the real-time current signal to the control system; and The control system is used to send out control signals and also to receive real-time current signals and switch alarm signals output by the output unit.

7. The device according to claim 6, It is characterized in that The control system is also used to record the real-time current signal, and draw a standard current dynamic curve or determine the steady-state current value based on the real-time current signal when the solenoid valve is working normally in the historical records, and then determine the alarm threshold based on the steady-state current value. The control system is also used to communicate the steady-state current value and the alarm threshold or the standard current dynamic curve to the control unit through the output unit.

8. A fault detection method for a multi-channel solenoid valve, the method include: Detecting the presence or absence of a control signal at the input side of the driver of each channel, wherein the input end of the driver is connected to the positive and negative ends of the control signal of each channel, for driving the solenoid valve of each channel; as well as When there is a control signal on the input side of the driver, it triggers the acquisition of the real-time current signal of the solenoid valve in the channel corresponding to the driver, and determines whether the circuit of the channel corresponding to the driver is abnormal, and then issues an alarm signal, wherein, For a channel using an interlocking solenoid valve, the real-time current value is collected by slow sampling, and compared with the steady-state current value when the interlocking solenoid valve is working normally, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, it is determined that an abnormality occurs in the circuit of the channel, and an alarm signal is issued; and For the channel of the application programmable solenoid valve, the real-time current value is collected by high-speed sampling, and a real-time current dynamic curve is drawn according to the collected real-time current value, and a judgment interval (T0-T1) of the real-time current dynamic curve is determined. Compared with the standard current dynamic curve, when the difference between the maximum peak current and the minimum valley current of the real-time current dynamic curve in the judgment interval (T0-T1) exceeds the alarm interval of the standard current dynamic curve, it is judged that an abnormality occurs in the circuit of the channel and an alarm signal is issued, wherein T0 corresponds to the moment when the current isolation sampling unit of the channel is triggered, and T1 corresponds to the moment when the real-time current value reaches a preset percentage value of the steady-state current value.

9. The method according to claim 8, in, The peak current maximum value and the valley current minimum value are determined by: For the real-time current dynamic curve within the judgment interval (T0-T1), a slope value is calculated every N sampling points, and the points whose absolute values ​​of the slope values ​​are closest to 0 are determined as the peak points and valley points on the real-time current dynamic curve; Determine the highest peak point among the peak points of the real-time current dynamic curve, and take the peak current corresponding to the highest peak point as the peak current maximum value; as well as The lowest valley point among the valley points of the real-time current dynamic curve is determined, and the valley point current corresponding to the lowest valley point is used as the minimum valley point current value.

10. The method according to claim 8, in, For the channel of the application programmable solenoid valve, after the collected real-time current value reaches the steady-state current value, the real-time current value is collected by slow sampling. Compared with the steady-state current value, when the difference between the real-time current value and the steady-state current value exceeds the alarm threshold, it is judged that the circuit of the channel is abnormal and an alarm signal is issued.

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