A solenoid valve state monitoring circuit

Abstract

The present application relates to a solenoid valve state monitoring circuit, which belongs to the technical field of solenoid valves. The state monitoring circuit includes: a driving circuit and a detection circuit: the driving circuit includes: a charging resistor R2, one end of which is externally connected to a power supply; a charging unit, an input end connected to the other end of the charging resistor R2; a first NPN type switch tube N1, the emitter of which is grounded and connected to the second output end of the charging unit, based on an external controller; a solenoid valve interface, a diode D1 is connected in parallel, one end of which is connected to the first output end of the charging unit, and the other end is connected to the collector of the first NPN type switch tube N1; a first voltage divider unit, an input end connected to the first output end of the charging unit, a first output end connected to one end of the solenoid valve interface, and a second output end grounded; a detection circuit includes: a comparator U1A, a same-direction input end connected to the first voltage divider unit, a reverse input end connected to a reference voltage, and an output end connected to a controller. The present application has the beneficial effect of facilitating the final state monitoring of the solenoid valve.

Description

Technical Field

[0001] The present application relates to the technical field of solenoid valves, and in particular to a solenoid valve state monitoring circuit. Background Art

[0002] At present, the conventional principle of solenoid valves is mainly to drive the electromagnet through the coil, and control the movement of the electromagnet by turning on and off the power to realize the opening and closing of the solenoid valve. For customers who often use solenoid valves, customers need to know whether the final state of the solenoid valve is in the open state or the closed state.

[0003] Currently, solenoid valves usually have two control modes, manual control and electric control, at the same time. If the staff manually opens or closes the solenoid valve after the solenoid valve is closed or opened, the control system is often unable to know. In order to determine the current actual state of the solenoid valve, a micro switch is usually built-in and an output wire is added to feed back the position to other electrical equipment; but this requires redesigning and processing the solenoid valve, which is relatively complicated. Utility Model Content

[0004] In order to facilitate the monitoring of the final state of the solenoid valve, the present application provides a solenoid valve state monitoring circuit; no change is made to the structure of the solenoid valve, the method is simple, easy to implement, and is suitable for electromagnetic emergency shut-off valves; the following technical solutions are adopted:

[0005] A solenoid valve state monitoring circuit includes a drive circuit and a detection circuit:

[0006] The driving circuit comprises:

[0007] Charging resistor R2, one end of which is connected to an external power supply;

[0008] A charging unit, an input end of which is connected to the other end of the charging resistor R2;

[0009] A first NPN type switch tube N1, the emitter of which is grounded and connected to the second output terminal of the charging unit, based on an external controller;

[0010] The solenoid valve interface is connected in parallel with a diode D1, one end of which is connected to the first output end of the charging unit, and the other end of which is connected to the collector of the first NPN type switch tube N1;

[0011] A first voltage dividing unit, wherein the input end is connected to the first output end of the charging unit, the first output end is connected to one end of the solenoid valve interface, and the second output end is grounded;

[0012] The detection circuit comprises:

[0013] The comparator U1A has a non-inverting input terminal connected to the first voltage divider unit, a reverse input terminal connected to a reference voltage, and an output terminal connected to the controller.

[0014] By adopting the above technical solution, when the combustible gas detector detects that the concentration of combustible gas is greater than the concentration threshold, the base of the first NPN switch tube N1 applies a high level, the charging unit releases energy, the drive circuit loop is turned on, and the solenoid valve is closed; the comparator U1A compares the voltage of the same-direction input terminal and the reverse input terminal to output high and low levels, and the duration of the high and low levels is convenient for determining the final state of the solenoid valve. Due to the different positions of the solenoid valves, the inductance presented to the outside is also different, and the solenoid valve is transiently given a charging process, and the duration of the charging transition process is different.

[0015] Optionally, the driving circuit further includes:

[0016] A second voltage dividing unit, wherein the input end is connected to the collector of the first NPN type switch tube N1 and the output end is grounded;

[0017] The inverting input terminal of the comparator U1A is connected to the second voltage dividing unit.

[0018] Optionally, the detection circuit further includes:

[0019] A second NPN switch tube N2, with a base connected to the output end of the comparator U1A, an emitter connected to the ground, and a collector connected to the controller;

[0020] The pull-up resistor R1 has one end connected to the collector of the second NPN switch tube N2 and the other end connected to the power supply VCC.

[0021] By adopting the above technical solution, when the comparator U1A outputs a high level, the second NPN type switch tube N2 is turned on, and the controller detects that the collector of the second NPN type switch tube N2 is a low level; when the comparator U1A outputs a low level, the second NPN type switch tube N2 is turned off, and the controller detects that the collector of the second NPN type switch tube N2 is a high level; the controller determines whether the final state of the solenoid valve is in the open state or the closed state by detecting the pulse width length of the collector pin of the second NPN type switch tube N2, and the pulse width length when the solenoid valve is open is longer than the pulse width length when the solenoid valve is closed; thereby, it is convenient to monitor the state of the solenoid valve without making any changes to the solenoid valve, and the method is simple and easy to implement.

[0022] Optionally, the charging unit includes:

[0023] A first electrolytic capacitor C1;

[0024] The second electrolytic capacitor C2 is connected in parallel with the first electrolytic capacitor C1; the positive electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected to the other end of the charging resistor R2 and to the input end of the first voltage divider unit; the negative electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected to the output end of the first voltage divider unit.

[0025] By adopting the above technical solution, under normal conditions, the first NPN switch tube N1 is in the cut-off state, and the power supply charges the first electrolytic capacitor C1 and the second electrolytic capacitor C2 through the charging resistor R2 to store energy; when the first NPN switch tube N1 is turned on, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 release energy.

[0026] Optionally, the first voltage dividing unit includes:

[0027] A first voltage-dividing resistor R3, one end of which is connected to the positive electrode of the second electrolytic capacitor C2 and to one end of the solenoid valve interface;

[0028] The second voltage-dividing resistor R4 has one end connected in series with the other end of the first voltage-dividing resistor R3 and the other end grounded; the non-inverting input end of the comparator U1A is connected to the other end of the first voltage-dividing resistor R3 and one end of the second voltage-dividing resistor R4.

[0029] Optionally, the second voltage dividing unit includes:

[0030] A third NPN type switch tube N3, the base of which is connected to the controller, the emitter of which is grounded, and the collector of which is connected to the other end of the solenoid valve interface;

[0031] A third voltage-dividing resistor R5, one end of which is connected to the collector of the third NPN-type switch tube N3;

[0032] The fourth voltage-dividing resistor R6 has one end connected in series with the other end of the third voltage-dividing resistor R5 and the other end connected to ground. The inverting input end of the comparator is connected to the other end of the third voltage-dividing resistor R5 and one end of the fourth voltage-dividing resistor R6.

[0033] By adopting the above technical solution, when the state of the solenoid valve is detected, the third NPN switch tube N3 is driven to be turned on, and the charging unit charges the solenoid valve to store energy.

[0034] Optionally, the second voltage dividing unit further includes:

[0035] The current limiting and sampling resistor R7 has one end connected to the collector of the third NPN type switch tube N3 , and the other end connected to one end of the third voltage dividing resistor R5 .

[0036] By adopting the above technical solution, the current flowing through the solenoid valve coil is limited to prevent the solenoid valve from malfunctioning, and the voltage change trend of the negative terminal of the solenoid valve is collected.

[0037] In summary, the present application has at least the following beneficial effects:

[0038] Due to the different positions of the solenoid valves, the inductance presented to the outside is also different, and a charging process is transiently given to the solenoid valve. Since the duration of the charging transition process is different, the comparator U1A, the second NPN type switch tube N2 and the pull-up resistor R1 are set to shape a pulse, so that the controller can detect the pulse width length of the collector pin of the second NPN type switch tube N2, and then directly determine whether the final state of the solenoid valve is open or closed through the pulse width length, thereby eliminating the need to make any changes to the solenoid valve. The method is simple and easy to implement, and is convenient for monitoring the state of the solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a circuit structure diagram of a monitoring circuit according to a first embodiment of the present application;

[0040] Figure 2 It is the waveform diagram when the solenoid valve is opened;

[0041] Figure 3 It is the waveform diagram when the solenoid valve is closed.

[0042] Description of the accompanying drawings: 100, driving circuit; 110, charging unit; 120, first voltage dividing unit; 130, second voltage dividing unit; 200, detection circuit. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the following will be combined with the appended Figure 1 -Attached Figure 3 , the technical solutions in the embodiments of the utility model are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0044] The present application embodiment discloses a solenoid valve state monitoring circuit. Figure 1 As an implementation of the monitoring circuit, the monitoring circuit may include a driving circuit 100 and a detection circuit 200 .

[0045] The driving circuit 100 may include a charging resistor R2 , a charging unit 110 , a first voltage dividing unit 120 , a first NPN type switch tube N1 , a solenoid valve interface and a second voltage dividing unit 130 .

[0046] One end of the charging resistor R2 is connected to an external power supply, and the power supply voltage is within the power supply voltage range of the combustible gas detector, which is usually 9V-12V, and can be 12V in this application; the other end of the charging resistor R2 is connected to the input end of the charging unit 110.

[0047] The first output end of the charging unit 110 is connected to the input end of the first voltage dividing unit 120 , and the second output end of the charging unit 110 is connected to the second output end of the first voltage dividing unit 120 and is grounded.

[0048] The solenoid valve interface is connected to the solenoid valve, one end of the solenoid valve interface is connected to the first output end of the first voltage divider unit 120, and the other end is connected to the collector of the first NPN type switch tube N1. The solenoid valve interface is connected in parallel with a diode D1, the positive electrode of the diode D1 is connected to the other end of the solenoid valve interface, and the negative electrode of the diode D1 is connected to one end of the solenoid valve interface.

[0049] The base of the first NPN type switch tube N1 is externally connected to a controller, and the emitter is connected to the output end of the first voltage dividing unit 120 and is grounded. The controller may be a single chip microcomputer.

[0050] The input end of the second voltage dividing unit 130 is connected to the collector of the first NPN type switch tube N1 , and the output end is grounded and connected to the emitter of the first NPN type switch tube N1 .

[0051] When the controller gives a high level to the base of the first NPN switch tube N1, the first NPN switch tube N1 is turned on, the loop of the solenoid valve driving circuit 100 is turned on, and the solenoid valve is closed.

[0052] The charging unit 110 may include a first electrolytic capacitor C1 and a second electrolytic capacitor C2.

[0053] The first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected in parallel; the positive electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected to the other end of the charging resistor R2 and to the input end of the first voltage divider unit 120. The negative electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected to the second output end of the first voltage divider unit 120.

[0054] The first voltage dividing unit 120 may include a first voltage dividing resistor R3 and a second voltage dividing resistor R4 .

[0055] One end of the first voltage-dividing resistor R3 is connected to the positive electrode of the second electrolytic capacitor C2 and to one end of the solenoid valve interface. One end of the second voltage-dividing resistor R4 is connected in series with the other end of the first voltage-dividing resistor R3, and the other end of the second voltage-dividing resistor R4 is grounded. The first input end of the detection circuit 200 is connected to the other end of the first voltage-dividing resistor R3 and one end of the second voltage-dividing resistor R4.

[0056] The second voltage dividing unit 130 may include a current limiting and sampling resistor R7 , a third NPN switch tube N3 , a third voltage dividing resistor R5 , and a fourth voltage dividing resistor R6 .

[0057] Among them, one end of the current limiting and sampling resistor R7 is connected to the collector of the third NPN type switch tube N3, and the other end is connected to one end of the third voltage-dividing resistor R5; the base of the third NPN type switch tube N3 is connected to the controller, the emitter is grounded, and the collector is connected to the other end of the solenoid valve interface; the other end of the third voltage-dividing resistor R5 is connected in series with one end of the fourth voltage-dividing resistor R6; the other end of the fourth voltage-dividing resistor R6 is grounded. The second input end of the detection circuit 200 is connected to the other end of the third voltage-dividing resistor R5 and one end of the fourth voltage-dividing resistor R6.

[0058] As an implementation of the detection circuit 200 , the detection circuit 200 may include a comparator U1A, a second NPN switch tube N2 , and a pull-up resistor R1 .

[0059] The comparator U1A has a non-inverting input terminal connected to the other end of the first voltage-dividing resistor R3 and one end of the second voltage-dividing resistor R4, and a reverse input terminal connected to the other end of the third voltage-dividing resistor R5 and one end of the fourth voltage-dividing resistor R6.

[0060] The base of the second NPN switch tube N2 is connected to the output end of the comparator U1A, the emitter is grounded, and the collector is connected to the controller; when the comparator U1A outputs a high level, the second NPN switch tube N2 is turned on.

[0061] One end of the pull-up resistor R1 is connected to the collector of the second NPN switch tube N2, and the other end is connected to the power supply VCC.

[0062] The controller generates a pulse width waveform according to the collected level signal of the collector of the second NPN switch tube N2; Figure 2 and Figure 3 shown.

[0063] The implementation principle of this embodiment is:

[0064] When the combustible gas detector detects that the combustible gas concentration is greater than the concentration threshold, the controller applies a high level to the base of the first NPN switch tube N1, the first NPN switch tube N1 is turned on, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 release energy, the electromagnetic drive circuit loop is turned on, and the electromagnetic valve is closed;

[0065] The comparator U1A compares the voltage of the non-inverting input terminal and the reverse input terminal; when the comparator U1A outputs a high level, the second NPN type switch tube N2 is turned on, and the controller detects that the collector is at a low level; when the comparator U1A outputs a low level, the second NPN type switch tube N2 is turned off, and the controller detects that the collector of the second NPN type switch tube N2 is at a high level; the controller determines whether the solenoid valve is in an open or closed state by detecting the pulse width length of the collector pin of the second NPN type switch tube N2, and the pulse width length when the solenoid valve is open is longer than the pulse width length when the solenoid valve is closed; thereby, it is convenient to monitor the final state of the solenoid valve without making any changes to the solenoid valve, and the method is simple and easy to implement.

[0066] It should be noted that when the solenoid valve is abnormal, for example, when the solenoid valve is in an open circuit state, the collector pin of the second NPN switch tube N2 is always at a low level; when the solenoid valve is in a short circuit state, the collector pin of the second NPN switch tube N2 is always at a high level.

[0067] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application in sequence. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A solenoid valve state monitoring circuit, characterized in that: It includes a driving circuit (100) and a detection circuit (200): The driving circuit (100) comprises: Charging resistor R2, one end of which is connected to an external power supply; A charging unit (110), the input end of which is connected to the other end of the charging resistor R2; A first NPN type switch tube N1, the emitter of which is grounded and connected to the second output end of the charging unit (110), based on an external controller; A solenoid valve interface, connected in parallel with a diode D1, one end of which is connected to the first output end of the charging unit (110), and the other end of which is connected to the collector of the first NPN type switch tube N1; A first voltage dividing unit (120), the input end of which is connected to the first output end of the charging unit (110), the first output end of which is connected to one end of the solenoid valve interface, and the second output end of which is grounded; The detection circuit (200) comprises: The comparator U1A has a non-inverting input terminal connected to the first voltage dividing unit (120), a reverse input terminal connected to a reference voltage, and an output terminal connected to a controller.

2. A solenoid valve state monitoring circuit according to claim 1, characterized in that: The driving circuit (100) further includes: A second voltage dividing unit (130), the input end of which is connected to the collector of the first NPN type switch tube N1, and the output end of which is grounded; The inverting input terminal of the comparator U1A is connected to the second voltage dividing unit (130).

3. The solenoid valve state monitoring circuit according to claim 2, characterized in that: The detection circuit (200) further includes: A second NPN switch tube N2, with a base connected to the output end of the comparator U1A, an emitter connected to the ground, and a collector connected to the controller; The pull-up resistor R1 has one end connected to the collector of the second NPN switch tube N2 and the other end connected to the power supply VCC.

4. The solenoid valve state monitoring circuit according to claim 1, characterized in that: The charging unit (110) comprises: A first electrolytic capacitor C1; A second electrolytic capacitor C2 is connected in parallel with the first electrolytic capacitor C1; the positive electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are both connected to the other end of the charging resistor R2 and to the input end of the first voltage divider unit (120); and the negative electrodes of the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are both connected to the output end of the first voltage divider unit (120).

5. The solenoid valve state monitoring circuit according to claim 4, characterized in that: The first voltage dividing unit (120) comprises: A first voltage-dividing resistor R3, one end of which is connected to the positive electrode of the second electrolytic capacitor C2 and to one end of the solenoid valve interface; The second voltage-dividing resistor R4 has one end connected in series with the other end of the first voltage-dividing resistor R3 and the other end grounded; the non-inverting input end of the comparator U1A is connected to the other end of the first voltage-dividing resistor R3 and one end of the second voltage-dividing resistor R4.

6. The solenoid valve state monitoring circuit according to claim 2, characterized in that: The second voltage dividing unit (130) comprises: A third NPN type switch tube N3, the base of which is connected to the controller, the emitter of which is grounded, and the collector of which is connected to the other end of the solenoid valve interface; A third voltage-dividing resistor R5, one end of which is connected to the collector of the third NPN-type switch tube N3; The fourth voltage-dividing resistor R6 has one end connected in series with the other end of the third voltage-dividing resistor R5 and the other end connected to ground. The inverting input end of the comparator is connected to the other end of the third voltage-dividing resistor R5 and one end of the fourth voltage-dividing resistor R6.

7. The solenoid valve state monitoring circuit according to claim 6, characterized in that: The second voltage dividing unit (130) further includes: The current limiting and sampling resistor R7 has one end connected to the collector of the third NPN type switch tube N3 , and the other end connected to one end of the third voltage dividing resistor R5 .

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