Solenoid valve state monitoring system

Abstract

The invention discloses an electromagnetic valve state monitoring system, relates to the technical field of electromagnetic valve power supply system monitoring, and provides two control modes for different application scenes, which can effectively monitor the state of an electromagnetic valve. Originally, the abnormal working of the electromagnetic valve can be judged only through an abnormal phenomenon after the electromagnetic valve is enabled to work, and the system can independently monitor the state of the electromagnetic valve and is not influenced by an enabling instruction issued by a superior system. The system can immediately position the abnormality of the electromagnetic valve when the state of the electromagnetic valve is abnormal. Meanwhile, when the electromagnetic valve driving unit is abnormal, the electromagnetic valve monitoring unit can judge that the electromagnetic valve is in a normal state, so that the fault point is deduced to be the electromagnetic valve driving unit instead of the electromagnetic valve mechanism. In addition, whether the fault mode of the electromagnetic valve is short circuit, open circuit or impedance change can be accurately positioned, and a reference is provided for maintenance and optimization of a subsequent complete machine system.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic valve power supply system monitoring, in particular to an electromagnetic valve state monitoring system. Background Art

[0002] Solenoid valves are automated components that use electromagnetics to control fluids. For normally closed solenoid valves, when the solenoid coil of the solenoid valve is energized, the solenoid coil generates electromagnetic suction, which overcomes the elastic force of the spring to lift the valve core and open the valve; when the solenoid valve coil is de-energized, the solenoid coil no longer generates electromagnetic suction, and the closing element is pressed on the valve seat under the action of the spring force, closing the valve. The solenoid coil of the solenoid valve is wound with wire, and its equivalent circuit model is a series circuit of resistance and inductance. Its resistive component is affected by the internal resistance of the wire, and its inductive component mainly depends on the number of coil turns (N), the cross-sectional area of ​​the coil (S), the magnitude of the current flowing through it (I), and the relative magnetic permeability (μ) of the magnetic core material.

[0003] The solenoid valve is a current-controlled action mechanism. If its impedance characteristics change, it is usually difficult to distinguish whether it is a problem with the solenoid valve mechanism or the solenoid valve drive unit. If there is a problem with either of them, the solenoid valve will behave abnormally and fail to complete the specified task. The solenoid valve drive current waveform is as follows: Figure 4 shown.

[0004] Figure 4 In the equation, Imax is the solenoid valve activation current value, Imin is the solenoid valve holding current value, and t 1 ~t 2 The solenoid valve activation current build-up time, t 2 ~t 3 is the solenoid valve activation time, t 3 ~t 4 is the conversion time of the solenoid valve from the activated state to the held state, t 4 ~t n0 is the solenoid valve holding time, t n1 ~t n2 is the solenoid valve closing time.

[0005] The resistive component of the solenoid valve determines the required solenoid valve activation current value and the solenoid valve holding current value. The inductive component of the solenoid valve will affect the speed of the conversion time. For example, the larger the inductive component of the solenoid valve, the longer the solenoid valve activation current establishment time, the conversion time of the solenoid valve from the activation state to the holding state, and the solenoid valve closing time will become.

[0006] The existing solution is to physically isolate the solenoid valve drive unit and the solenoid valve mechanism, then connect a standard solenoid valve simulation load to the back stage of the solenoid valve drive unit, control the solenoid valve drive unit normally, check whether the solenoid valve simulation load is normal, and then use a standard drive power supply to provide a qualified drive power supply to the solenoid valve mechanism to check whether the solenoid valve mechanism is working normally.

[0007] In the specific implementation, the scheme adopted by the prior art is mainly based on multi-point control and monitoring of the driving current provided by the solenoid valve driving unit to determine whether the system failure is caused by the abnormality of the solenoid valve driving unit, and its main target is the solenoid valve driving unit.

[0008] The above existing solutions have the following problems:

[0009] First, when troubleshooting the problem, it is necessary to physically isolate the solenoid valve drive unit and the solenoid valve mechanism, that is, disconnect the drive power line. Since the main control system, drive system, and operating actuator of most control systems may be distributed in different places, manual physical isolation will cost a lot of time and effort.

[0010] Secondly, it is necessary to prepare a standard solenoid valve simulation load and a standard drive power supply. This condition is difficult to meet in the actual industrial control site, and the cost of preparing a set of standard solenoid valve simulation loads and a standard drive power supply as backup for troubleshooting is too high.

[0011] Thirdly, the problem locating process is complicated. First, it is necessary to ensure that the connecting wires are correctly and effectively connected. Secondly, it is impossible to guarantee whether the so-called standard solenoid valve simulation load and standard drive power supply themselves have quality problems. Summary of the invention

[0012] In view of the above problems, the present invention provides a solenoid valve state monitoring system for overcoming the above problems or at least partially solving the above problems, and solves the problem of fault differentiation between the solenoid valve power supply system and the solenoid valve mechanism.

[0013] The present invention provides the following scheme:

[0014] A solenoid valve state monitoring system, comprising:

[0015] A solenoid valve driving unit, the solenoid valve driving unit is used to output a driving current to the controlled solenoid valve;

[0016] A solenoid valve monitoring unit, the solenoid valve monitoring unit comprising a monitoring controller, a monitoring power supply, a second switch MOS tube, a second constant current MOS tube, a second constant current control circuit, a second sampling resistor and a second recovery circuit; the second switch MOS tube is respectively connected to the monitoring controller and the second constant current MOS tube, the second constant current control circuit is respectively connected to the monitoring controller and the second constant current MOS tube, and the second constant current MOS tube is connected to the controlled solenoid valve; the second sampling resistor is respectively connected to the controlled solenoid valve and the second sampling circuit, and the second sampling circuit is connected to the monitoring controller;

[0017] The monitoring controller is used to perform the following operations:

[0018] According to the determination of the enabling logic control switch circuit is turned on to provide the monitoring current to the controlled solenoid valve; the switch circuit includes the second switch MOS tube, the second constant current control circuit and the second constant current MOS tube;

[0019] Determining that the monitoring current acts only on the second sampling resistor, and determining that the voltage value monitored by the drain-source voltage monitoring circuit of the second constant current MOS tube suddenly changes to a target value, then determining that the controlled solenoid valve is short-circuited;

[0020] Determining that there is no voltage difference on the second sampling resistor and that the second sampling circuit does not collect data, then determining that the controlled solenoid valve is short-circuited;

[0021] It is determined that the monitoring current acts on the controlled solenoid valve and the second sampling resistor, and it is determined that the voltage value monitored by the second constant current MOS tube through the drain-source voltage monitoring circuit is offset from the normal value, then it is determined that the impedance characteristics of the controlled solenoid valve have changed, and an alarm is sent to the system.

[0022] Preferably, if the voltage value offset exceeds a preset offset threshold, it is determined that the controlled solenoid valve needs to be replaced or repaired if it is able to complete the execution task.

[0023] Preferably: the enabling logic includes controlling the switch circuit to be in a normally open state or controlling the switch circuit to be turned on after receiving an enabling instruction sent by a superior system.

[0024] Preferably: the enabling logic controls the switch circuit to turn on after receiving an enabling instruction sent by the upper system;

[0025] The monitoring controller is also used to determine that the state of the controlled solenoid valve is normal, and transmit a solenoid valve enabling instruction to the solenoid valve driving unit, so that the solenoid valve is activated and works normally;

[0026] It is determined that the state of the controlled solenoid valve is abnormal, and no solenoid valve enabling instruction is transmitted to the solenoid valve driving unit.

[0027] Preferably: the solenoid valve driving unit comprises a main controller, a main driving power supply, a first switch MOS tube, a first constant current control circuit, a first constant current MOS tube, a signal conditioning circuit and a DC / DC conversion circuit; the first switch MOS tube, the first constant current control circuit and the signal conditioning circuit are all connected to the main controller, the DC / DC conversion circuit is respectively connected to the main driving power supply, the signal conditioning circuit and the first switch MOS tube, the first constant current MOS tube is respectively connected to the first switch MOS tube and the first constant current control circuit, and the first constant current MOS tube is connected to the controlled solenoid valve;

[0028] The main controller is used to output a driving current to the controlled solenoid valve by controlling the signal conditioning circuit, the first constant current control circuit and the first switch MOS tube after receiving the solenoid valve enabling instruction issued by the upper system.

[0029] Preferably: the first constant current control circuit includes a digital-to-analog converter and an operational amplifier circuit, the digital-to-analog converter is used to output a reference voltage according to an instruction issued by the main controller, and the operational amplifier circuit is used to condition the reference voltage to obtain the gate-source voltage required by the first constant current MOS tube.

[0030] Preferably: the first constant current MOS tube comprises a power type N-channel field effect MOS tube.

[0031] Preferably, the solenoid valve driving unit further includes a first sampling resistor and a first recovery circuit, the first sampling resistor is connected to the controlled solenoid valve, and the first recovery circuit is connected to the main controller.

[0032] Preferably: the first sampling circuit includes an operational amplifier circuit and an analog-to-digital converter; the operational amplifier circuit is used to transmit the voltage difference across the first sampling resistor to the analog-to-digital converter after operational amplifier conditioning, so that the analog-to-digital converter converts the analog signal into a digital signal and sends it to the main controller.

[0033] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] A solenoid valve status monitoring system provided in an embodiment of the present application provides two control methods for different application scenarios, both of which can effectively monitor the status of the solenoid valve. Originally, the solenoid valve could only be judged to be abnormal through abnormal phenomena after the solenoid valve was enabled to work. This system can independently monitor the status of the solenoid valve without being affected by the enable command issued by the superior system. The system can immediately locate the abnormality of the solenoid valve when the solenoid valve state is abnormal. At the same time, when the solenoid valve drive unit is abnormal, it can be determined through the solenoid valve monitoring unit that the solenoid valve is in a normal state, so as to infer that the fault point is the solenoid valve drive unit, rather than the solenoid valve mechanism itself. In addition, it can accurately locate the fault mode of the solenoid valve, whether it is a short circuit, an open circuit or an impedance change, which provides a reference for the subsequent maintenance and optimization of the entire system.

[0035] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 is a schematic diagram of a solenoid valve state monitoring system provided by an embodiment of the present invention;

[0038] Figure 2 1 is a comparison diagram of the solenoid valve current waveform provided by an embodiment of the present invention (the switch circuit is in a normally open state);

[0039] Figure 3 It is a comparison diagram of the solenoid valve current waveform provided by an embodiment of the present invention (the control switch circuit is turned on after receiving the enable instruction issued by the upper system);

[0040] Figure 4 1 is a solenoid valve driving current waveform diagram provided by an embodiment of the present invention.

[0041] In the figure: solenoid valve drive unit 1, main controller 11, main drive power supply 12, first switch MOS tube 13, first constant current control circuit 14, first constant current MOS tube 15, signal conditioning circuit 16, DC / DC conversion circuit 17, first sampling resistor 18, first recovery circuit 19, solenoid valve monitoring unit 2, monitoring controller 21, monitoring power supply 22, second switch MOS tube 23, second constant current MOS tube 24, second constant current control circuit 25, second sampling resistor 26, second recovery circuit 27, controlled solenoid valve 3. DETAILED DESCRIPTION

[0042] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0043] See also Figure 1 , is a solenoid valve state monitoring system provided by an embodiment of the present invention, such as Figure 1 As shown, the system may include:

[0044] A solenoid valve driving unit 1, wherein the solenoid valve driving unit 1 is used to output a driving current to a controlled solenoid valve 3;

[0045] A solenoid valve monitoring unit 2, the solenoid valve monitoring unit 2 includes a monitoring controller 21, a monitoring power supply 22, a second switch MOS tube 23, a second constant current MOS tube 24, a second constant current control circuit 25, a second sampling resistor 26 and a second recovery circuit 27; the second switch MOS tube 23 is respectively connected to the monitoring controller 21 and the second constant current MOS tube 24, the second constant current control circuit 25 is respectively connected to the monitoring controller 21 and the second constant current MOS tube 24, the second constant current MOS tube 24 is connected to the controlled solenoid valve 3; the second sampling resistor 26 is respectively connected to the controlled solenoid valve 3 and the second sampling circuit, and the second sampling circuit is connected to the monitoring controller 21;

[0046] The monitoring controller 21 is used to perform the following operations:

[0047] According to the determination of the enabling logic control switch circuit, the switch circuit is turned on to provide the monitoring current to the controlled solenoid valve 3; the switch circuit includes the second switch MOS tube 23, the second constant current control circuit 25 and the second constant current MOS tube 24;

[0048] Determine that the monitoring current acts only on the second sampling resistor 26, and determine that the voltage value monitored by the drain-source voltage monitoring circuit of the second constant current MOS tube 24 suddenly changes to a target value, then determine that the controlled solenoid valve 3 is short-circuited;

[0049] If it is determined that there is no voltage difference on the second sampling resistor 26 and the second sampling circuit 27 does not collect data, it is determined that the controlled solenoid valve 3 is open circuited;

[0050] It is determined that the monitoring current acts on the controlled solenoid valve 3 and the second sampling resistor 26, and it is determined that the voltage value monitored by the second constant current MOS tube 24 through the drain-source voltage monitoring circuit is offset compared with the normal value, then it is determined that the impedance characteristics of the controlled solenoid valve 3 have changed, and an alarm is sent to the system.

[0051] The solenoid valve status monitoring system provided in the embodiment of the present application solves the problem that it is difficult to locate the fault of the solenoid valve mechanism. Regardless of whether the system is in a normal working state or an abnormal working state, the system can monitor and record the impedance characteristics of the solenoid valve. Once the solenoid valve works abnormally, by querying the monitored solenoid valve status information, it can immediately locate whether it is a problem with the solenoid valve drive unit 1 or the solenoid valve itself, greatly shortening the troubleshooting time and reducing the difficulty and complexity of troubleshooting. For the production and operation of actual enterprises, it is conducive to quickly resuming production and reducing the cost of troubleshooting and maintenance.

[0052] In order to further improve the warning effect, the embodiment of the present application can provide that when the voltage value offset exceeds a preset offset threshold, it is determined that the controlled solenoid valve 3 needs to be replaced or repaired if it is able to complete the execution task.

[0053] The system provided in the present application can implement two monitoring methods. In specific implementations, different monitoring methods can be executed according to different enabling logics. For example, in one implementation method, the embodiment of the present application can provide the enabling logic including controlling the switch circuit to be in a normally open state or controlling the switch circuit to be turned on after receiving an enabling instruction issued by an upper-level system.

[0054] Furthermore, the enabling logic controls the switch circuit to turn on after receiving an enabling instruction sent by the upper system;

[0055] The monitoring controller 21 is also used to determine that the state of the controlled solenoid valve 3 is normal, and transmit a solenoid valve enabling instruction to the solenoid valve driving unit 1 so that the solenoid valve is activated and works normally;

[0056] It is determined that the state of the controlled electromagnetic valve 3 is abnormal, and no electromagnetic valve enabling instruction is transmitted to the electromagnetic valve driving unit 1 .

[0057] The solenoid valve drive unit 1 provided in the embodiment of the present application is used to provide a drive current for the solenoid valve. In specific implementation, the embodiment of the present application can also provide that the solenoid valve drive unit 1 includes a main controller 11, a main drive power supply 12, a first switch MOS tube 13, a first constant current control circuit 14, a first constant current MOS tube 15, a signal conditioning circuit 16 and a DC / DC conversion circuit 17; the first switch MOS tube 13, the first constant current control circuit 14 and the signal conditioning circuit are all connected to the main controller 11, the DC / DC conversion circuit 17 is respectively connected to the main drive power supply 12, the signal conditioning circuit and the first switch MOS tube 13, the first constant current MOS tube 15 is respectively connected to the first switch MOS tube 13 and the first constant current control circuit 14, and the first constant current MOS tube 15 is connected to the controlled solenoid valve 3;

[0058] The main controller 11 is used to output a driving current to the controlled solenoid valve 3 by controlling the signal conditioning circuit, the first constant current control circuit 14 and the first switch MOS tube 13 after receiving the solenoid valve enabling instruction issued by the upper system.

[0059] The first constant current control circuit 14 includes a digital-to-analog converter and an operational amplifier circuit, wherein the digital-to-analog converter is used to output a reference voltage according to an instruction issued by the main controller 11, and the operational amplifier circuit is used to adjust the reference voltage to obtain the gate-source voltage required by the first constant current MOS transistor 15. The first constant current MOS transistor 15 includes a power N-channel field effect MOS transistor.

[0060] The solenoid valve driving unit 1 further includes a first sampling resistor 18 and a first recovery circuit 19 . The first sampling resistor 18 is connected to the controlled solenoid valve 3 , and the first recovery circuit 19 is connected to the main controller 11 .

[0061] The first sampling circuit 19 includes an operational amplifier circuit and an analog-to-digital converter; the operational amplifier circuit is used to transmit the voltage difference across the first sampling resistor 18 to the analog-to-digital converter after operational amplifier conditioning, so that the analog-to-digital converter converts the analog signal into a digital signal and sends it to the main controller 11.

[0062] The system provided by this application is introduced in detail below.

[0063] The theoretical basis of the system provided by the embodiment of the present application is Kirchhoff's current law, that is, at any node in the circuit, at any time, the sum of the currents flowing into the node is equal to the sum of the currents flowing out of the node.

[0064] The system provided in the embodiment of the present application includes two parts, a solenoid valve drive unit 1 and a solenoid valve monitoring unit 2, wherein the solenoid valve drive unit 1 includes a main controller 11, a main drive power supply 12, a first switch MOS tube 13, a first constant current control circuit 14, a first constant current MOS tube 15, a signal conditioning circuit 16, a DC / DC conversion circuit 17, a first sampling resistor 18 and a first recovery circuit 19; the solenoid valve monitoring unit 2 is mainly composed of a monitoring controller 21, a monitoring power supply 22, a second switch MOS tube 23, a second constant current MOS tube 24, a second constant current control circuit 25, a second sampling resistor 26 and a second recovery circuit 27.

[0065] The monitoring power supply 22 is a low-voltage DC voltage source, which provides the necessary power supply for monitoring the impedance state of the solenoid valve. Its driving capacity is much smaller than that of the main driving power supply 12, and the driving current for monitoring that can be provided is far from the level of activating the solenoid valve. The main controller 11 increases the driving capacity through the triode by configuring the IO port to control the switch MOS tube to turn on and off the power supply path. The constant current MOS tube is a power-type N-channel field effect MOS tube, which makes the MOS tube work in the saturation region of the output characteristic curve. In this state, the drain current of the MOS tube is only related to the gate-source voltage, and is basically not affected by the change of the drain-source voltage, so as to achieve the purpose of constant current control. The drain-source voltage monitoring circuit mainly monitors the drain-source voltage of the constant current MOS tube. If the solenoid valve is short-circuited, the drain-source voltage value will rise. The constant current control circuit is mainly composed of a digital-to-analog converter, an operational amplifier, etc., to achieve effective regulation of the gate-source voltage of the above-mentioned constant current MOS tube. The sampling resistor is used to collect the reflux current. The sampling circuit is mainly composed of an operational amplifier and an analog-to-digital converter. The voltage difference between the two ends of the sampling resistor is transmitted to the analog-to-digital converter after a series of conditioning by the operational amplifier. The analog-to-digital converter then converts the analog signal into a digital signal and sends it to the monitoring controller 21. The principle block diagram is shown in FIG. Figure 1 shown.

[0066] Figure 1 The left part is the solenoid valve drive unit 1, which provides the normal operation of the solenoid valve. Figure 4 The driving current I 1 The right part is the solenoid valve monitoring unit 2, which mainly collects and monitors the current I 2 , determine whether the solenoid valve is abnormal.

[0067] In practical applications, the main controller 11 of the solenoid valve drive unit 1 receives the solenoid valve enable command issued by the upper system, and then outputs the drive current I to the solenoid valve through the control signal conditioning circuit, the first constant current control circuit 14 and the first switch circuit. 1If the solenoid valve is already in an abnormally damaged state, it cannot complete the specified action. When used with the solenoid valve monitoring unit 2, the following two control methods can be used to monitor the abnormal condition of the solenoid valve and avoid normal enabling.

[0068] One control method is that the enabling logic includes controlling the switch circuit to be in a normally open state. In specific implementation, the monitoring controller 21 controls the second switch circuit to be in a normally open state, so that the solenoid valve always has a monitoring current I 2 Flowing, current I 2 Compared with the driving current I 1 Much smaller (for example, if the normal drive current I 1 The activation current is 100mA, the holding current is 60mA, and the monitoring current I 2 5mA). According to the solenoid valve failure model, it can be roughly divided into short circuit, open circuit and slow change of impedance. When the solenoid valve is short-circuited, the current I 2 Only the second sampling resistor 26 is acted on, and the voltage value monitored by the drain-source voltage monitoring circuit of the second constant current MOS tube 24 suddenly changes to a larger value. At this time, the monitoring controller 21 infers that a short circuit occurs in the solenoid valve.

[0069] When the solenoid valve is disconnected, the monitoring current I 2 There is no voltage difference on the return path of the second sampling resistor 26, and the second sampling circuit 27 does not collect data. At this time, the monitoring controller 21 infers that the solenoid valve is open-circuited.

[0070] When the impedance of the solenoid valve changes slowly, the current I 2 Acting on the solenoid valve and the second sampling resistor 26, the second constant current MOS tube 24 detects that the voltage value is offset by a certain amount compared to the normal value through the drain-source voltage monitoring circuit. At this time, the monitoring controller 21 infers that the impedance characteristics of the solenoid valve have changed, and warns the system, and can even set a threshold. Once the threshold is exceeded, it means that the solenoid valve needs to be replaced or repaired while being able to complete the execution task. The current waveform comparison diagram flowing through the solenoid valve is shown in the figure below. Figure 2 shown.

[0071] Figure 2 Part A is the original solenoid valve drive current waveform, and part B is the solenoid valve current waveform with monitoring current superimposed. It can be seen from the figure that the solenoid valve needs to meet 100mA current to be successfully activated and used, and then 60mA current can maintain its working state. The additional 5mA monitoring current only adds 5mA bias on the basis of the original current waveform, which will not affect the normal drive of the solenoid valve.

[0072] Another control mode enabling logic includes controlling the switch circuit to open after receiving the enabling instruction sent by the upper system. In specific implementation, the upper system sends the solenoid valve enabling instruction to the monitoring controller 21 according to the preset timing, and the monitoring controller 21 controls the second switch circuit to open. After a period of time, the state of the solenoid valve is determined by referring to the above monitoring method. If the state of the solenoid valve is normal, the monitoring controller 21 transmits the solenoid valve enabling instruction to the main controller 11 of the solenoid valve drive unit 1, so that the solenoid valve is activated and works normally; if the monitoring controller 21 has detected that the state of the solenoid valve is abnormal, the monitoring controller 21 will not transmit the solenoid valve enabling instruction to the main controller 11 of the solenoid valve drive unit 1, so as to avoid unexpected erroneous actions of the solenoid valve.

[0073] like Figure 3 As shown, Figure 3 Part C in the figure is the original solenoid valve drive current waveform. Figure 3 Part D in the middle is the total current waveform flowing through the solenoid valve with monitoring current and timing control added. Figure 3 Part E in the middle is the total current waveform flowing through the solenoid valve when the solenoid valve is short-circuited. Figure 3 Part F in C is the total current waveform flowing through the solenoid valve when the solenoid valve is disconnected (no current at this time). Figure 3 It can be seen that under normal circumstances, after adding monitoring current and timing control, the overall control time of the solenoid valve will be delayed by a certain time than before. If the solenoid valve is detected to be abnormal, the total current flowing through the solenoid valve will be as follows Figure 3 The current conditions are shown in parts E and F of the figure.

[0074] The advantage of the former normally open control method is that the state of the solenoid valve can be monitored in real time, and the abnormal state of the solenoid valve can be known at any time. The disadvantage is that the monitoring power supply 22 needs to be loaded all the time, which wastes energy. The latter command control method is suitable for application scenarios that are not sensitive to the response time of the solenoid valve and energy-saving application scenarios. The advantage is energy saving, but the disadvantage is that it cannot meet the real-time requirements of some high-speed control application scenarios.

[0075] It can be seen that the system introduces the solenoid valve monitoring unit 2, which is distinguished from the original solenoid valve driving unit 1 and used as two functionally independent systems. (If the monitoring system is integrated into the solenoid valve driving unit 1, it will be difficult to distinguish whether it is a problem with the driving system or the monitoring system).

[0076] In summary, the solenoid valve state monitoring system provided in the embodiment of the present application provides two control methods for different application scenarios, both of which can effectively monitor the state of the solenoid valve. Originally, the solenoid valve could only be judged to be abnormal through abnormal phenomena after the solenoid valve was enabled to work. This system can independently monitor the state of the solenoid valve without being affected by the enable command issued by the superior system. The system can immediately locate the abnormality of the solenoid valve when the state of the solenoid valve is abnormal. At the same time, when the solenoid valve drive unit is abnormal, it can be determined through the solenoid valve monitoring unit that the solenoid valve is in a normal state, so as to infer that the fault point is the solenoid valve drive unit, rather than the solenoid valve mechanism itself. In addition, it is possible to accurately locate the fault mode of the solenoid valve, whether it is a short circuit, an open circuit or an impedance change, which provides a reference for the subsequent maintenance and optimization of the entire system.

[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article 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, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0078] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0079] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A solenoid valve status monitoring system, characterized in that: include: A solenoid valve driving unit, the solenoid valve driving unit is used to output a driving current to the controlled solenoid valve; A solenoid valve monitoring unit, the solenoid valve monitoring unit comprising a monitoring controller, a monitoring power supply, a second switch MOS tube, a second constant current MOS tube, a second constant current control circuit, a second sampling resistor and a second recovery circuit; the second switch MOS tube is respectively connected to the monitoring controller and the second constant current MOS tube, the second constant current control circuit is respectively connected to the monitoring controller and the second constant current MOS tube, and the second constant current MOS tube is connected to the controlled solenoid valve; the second sampling resistor is respectively connected to the controlled solenoid valve and the second sampling circuit, and the second sampling circuit is connected to the monitoring controller; The monitoring controller is used to perform the following operations: According to the determination of the enabling logic control switch circuit is turned on to provide the monitoring current to the controlled solenoid valve; the switch circuit includes the second switch MOS tube, the second constant current control circuit and the second constant current MOS tube; Determining that the monitoring current acts only on the second sampling resistor, and determining that the voltage value monitored by the drain-source voltage monitoring circuit of the second constant current MOS tube suddenly changes to a target value, then determining that the controlled solenoid valve is short-circuited; Determining that there is no voltage difference on the second sampling resistor and that the second sampling circuit does not collect data, then determining that the controlled solenoid valve is short-circuited; It is determined that the monitoring current acts on the controlled solenoid valve and the second sampling resistor, and it is determined that the voltage value monitored by the second constant current MOS tube through the drain-source voltage monitoring circuit is offset from the normal value, then it is determined that the impedance characteristics of the controlled solenoid valve have changed, and an alarm is sent to the system.

2. The solenoid valve status monitoring system according to claim 1, characterized in that: According to the voltage value offset exceeding the preset offset threshold, it is determined that the controlled solenoid valve needs to be replaced or repaired if it can complete the execution task.

3. The solenoid valve status monitoring system according to claim 1, characterized in that: The enabling logic includes controlling the switch circuit to be in a normally open state or controlling the switch circuit to be turned on after receiving an enabling instruction sent by a superior system.

4. The solenoid valve status monitoring system according to claim 1, characterized in that: The enabling logic controls the switch circuit to turn on after receiving an enabling instruction issued by the upper system; The monitoring controller is also used to determine that the state of the controlled solenoid valve is normal, and transmit a solenoid valve enabling instruction to the solenoid valve driving unit, so that the solenoid valve is activated and works normally; It is determined that the state of the controlled solenoid valve is abnormal, and no solenoid valve enabling instruction is transmitted to the solenoid valve driving unit.

5. The solenoid valve status monitoring system according to claim 1, characterized in that: The solenoid valve driving unit includes a main controller, a main driving power supply, a first switch MOS tube, a first constant current control circuit, a first constant current MOS tube, a signal conditioning circuit and a DC / DC conversion circuit; the first switch MOS tube, the first constant current control circuit and the signal conditioning circuit are all connected to the main controller, the DC / DC conversion circuit is respectively connected to the main driving power supply, the signal conditioning circuit and the first switch MOS tube, the first constant current MOS tube is respectively connected to the first switch MOS tube and the first constant current control circuit, and the first constant current MOS tube is connected to the controlled solenoid valve; The main controller is used to output a driving current to the controlled solenoid valve by controlling the signal conditioning circuit, the first constant current control circuit and the first switch MOS tube after receiving the solenoid valve enabling instruction issued by the upper system.

6. The solenoid valve status monitoring system according to claim 5, characterized in that: The first constant current control circuit includes a digital-to-analog converter and an operational amplifier circuit. The digital-to-analog converter is used to output a reference voltage according to an instruction issued by the main controller, and the operational amplifier circuit is used to condition the reference voltage to obtain the gate-source voltage required by the first constant current MOS tube.

7. The solenoid valve status monitoring system according to claim 5, characterized in that: The first constant current MOS tube comprises a power type N-channel field effect MOS tube.

8. The solenoid valve status monitoring system according to claim 5, characterized in that: The solenoid valve driving unit further includes a first sampling resistor and a first recovery circuit, wherein the first sampling resistor is connected to the controlled solenoid valve, and the first recovery circuit is connected to the main controller.

9. The solenoid valve status monitoring system according to claim 8, characterized in that: The first sampling circuit includes an operational amplifier circuit and an analog-to-digital converter; the operational amplifier circuit is used to transmit the voltage difference across the first sampling resistor to the analog-to-digital converter after operational amplifier conditioning, so that the analog-to-digital converter converts the analog signal into a digital signal and sends it to the main controller.

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