JP2582460B2 - Solenoid operation status detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the operating state of a solenoid, and more particularly, for operating, for example, an on-off valve or a switching valve and maintaining the state. The present invention relates to a solenoid operation state detection device that detects the operation state of a solenoid such as a latching solenoid used.

[Conventional technology]

Generally, when an on-off valve or a switching valve is operated, a solenoid driving circuit drives a latching solenoid by passing a driving current to a latching solenoid in response to an input of an on-off control signal or a switching control signal, and the driving of the latching solenoid The valve operates.

In such a case, since the valve may not be operated even when the control signal is input, it is necessary to confirm whether the valve has been operated reliably after the input of the control signal.

Conventionally, in order to confirm the operation of this valve, a reed switch is installed in the leakage magnetic flux generated by the latching solenoid, and the reed switch is turned on / off by utilizing the fact that the leakage magnetic flux differs depending on the operating state of the latching solenoid.
2. Description of the Related Art A solenoid operating state detecting device that generates an answerback signal indicating an operating state of a latching solenoid by performing off control is used.

However, in the configuration of the conventional operating state detecting device for the solenoid described above, the reed switch is turned on and off according to the magnitude of the leakage magnetic flux to generate an answer back signal. If the level varies, the operation state of the solenoid cannot be reliably answered back, so that it is necessary to finely adjust the installation position of the reed switch. In particular, in the case of a solenoid for which the efficiency, that is, the performance is improved, the leakage magnetic flux is extremely reduced, so that the inaccuracy of the on / off operation of the reed switch described above becomes more remarkable. In addition, since the reed switch has a mechanical contact piece, there is also a problem that reliability is inferior, such as a high possibility of failure due to wear of the contact piece.

Accordingly, the present applicant has proposed a new solenoid operation state detection device that can reliably detect the operation state of the solenoid without requiring troublesome adjustment and improve reliability.

The proposed device detects an operating state of a solenoid by flowing an AC signal (for example, a sine wave signal) to a solenoid coil and detecting a phase difference between the AC signal flowing through the coil and the original AC signal. Is what you do.

[Problems to be solved by the invention]

However, in the solenoid operating state detection device proposed above, an AC signal (for example, a sine wave signal) is passed through a coil of the solenoid, and a phase difference between the AC signal flowing through the coil and the original AC signal is detected. However, since the operation state of the solenoid is detected, there is a problem that the time until the operation state of the solenoid is detected becomes longer and the configuration is complicated.

Accordingly, an object of the present invention is to provide a solenoid operation state detection device that can detect the operation state of a solenoid in a short time and has a simple configuration.

[Means for solving the problem]

The operating state detection device of the solenoid was made by the present invention for solving the above problems, in the second state the movable piece 1 ₁ solenoid 1 from the first state or the second state the first
In the solenoid operating state detecting device for flowing the first or second driving current for driving the solenoid 1 to the coil L of the solenoid 1 and detecting the operating state of the solenoid 1 thereafter, After the drive current is passed through the coil L of the solenoid 1, the coil L of the solenoid 1
A detection signal output means 5a for outputting a detection signal to be supplied to the solenoid, and a detection means A for detecting an operation state of the solenoid 1 based on a duration of a voltage generated across the coil L of the solenoid 1 when the detection signal is supplied. It is characterized by having.

The detecting means A compares a voltage generated at both ends of the coil L of the solenoid 1 when the detection signal flows with a reference voltage, and a comparing means 4 for detecting a period in which the voltage at both ends exceeds the reference voltage. the a delay unit 6 for detecting signal for a predetermined time delay and output, the movable piece 1 ₁ of the suction state by the output of the comparison means 4 and the detection signal delayed by said delay means 6 are simultaneously present, It is characterized by having a latch means 7 for outputting the latched corresponding signal to the non-suction state of the movable piece 1 ₁ by not simultaneously present.

[Action]

In the above configuration, after the first or second drive current is applied to the coil L of the solenoid 1, a detection signal is applied to the coil L from the detection signal output means 5a, and the duration of the voltage generated at both ends of the coil L is determined. The detection means A monitors. At this time, the inductance of the coil L becomes different depending on the first or second operation state of the solenoid 1, and the voltage waveform generated at both ends of the coil L, particularly the duration, changes depending on the operation state. Detects the operating state of the solenoid 1 based on the duration of the voltage generated across the coil L.

In particular, in order to detect this operation state, the comparison means 4 compares the voltage generated at both ends of the coil L of the solenoid 1 when the detection signal is supplied with the reference voltage, and determines whether the voltage at both ends exceeds the reference voltage. And the delay means 6 delays the detection signal by a predetermined time and outputs it. Then, corresponding to the non-suction state of the movable piece 1 ₁ by the absence of the movable piece 1 ₁ of the suction state, at the same time by the output of the comparison means 4 and the detection signal delayed by the delay unit 6 is present at the same time The latch signal is latched and output by the latch means 7.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a circuit block diagram showing an embodiment of a solenoid operating state detecting device according to the present invention. Before describing this embodiment, the operating principle of the present invention will be described with reference to FIG.

FIG. 3 shows an example of the gas shut-off valve A. In FIG.
The gas shutoff valve A includes a latching solenoid 1, a valve body 10 operated by the latching solenoid 1,
It is constituted by a valve seat 11 having a valve hole 11 ₁ is opened and closed by. Also, latching solenoid 1 is a coil L, is constituted by the movable piece 1 ₁ and the magnet Mg, movable piece 1 ₁
Is provided integrally with the valve element 10. Gas shut-off valve A
The valve hole 11 ₁ is closed valve closed state (Fig. 3 right), and the valve hole 11 ₁ is opened valve open state (first when not in contact when the valve element 10 is in contact with the valve seat 11 3 left).

In the above configuration, when the DC valve opening current flows through the coil L of the latching solenoid 1 when the valve element 10 is in the valve closed state in contact with the valve seat 11, the movable piece ₁₁ is excited. When the excited magnetic pole of the movable piece 1 ₁ to set the direction of the valve opening current to match the poles of the magnet Mg, movable piece
1 ₁ is attracted to the magnet Mg against the spring, thereby the valve body 10 is a valve open state away from the valve seat 11.

Further, when a DC valve closing current in the opposite direction to the valve opening current is applied to the coil L from the valve open state, the movable piece ₁₁ is excited to be a magnetic pole in a direction to decrease the magnetic force of the magnet Mg. until at work spring force between the movable piece 1 ₁ and the magnet Mg that has been attracted to the magnet Mg moves the movable piece 1 _1, the valve body 10 is a valve-closed state abuts the valve seat 11.

When the latching solenoid 1 shifts from the valve opening state to the valve closing state or from the valve closing state to the valve opening state, a valve closing driving current or a valve opening driving current is respectively supplied to the coil L for a predetermined period, and thereafter the driving current stops flowing. Even so, the valve element 10 is configured to be maintained (latched) in that state.

Here, consider the inductance of the coil L of the latching solenoid 1, movable in the valve closing piece 1 ₁
The magnetic coupling between the coil and the coil L is greater than the magnetic coupling when the valve is opened. Therefore, since the former magnetic flux is larger than the latter magnetic flux, the inductance of the coil L when the valve is closed is larger than the inductance when the valve is open.

Referring back to FIG. 2, an embodiment of the solenoid operating state detecting device according to the present invention will be described.

A valve driving circuit 2 is connected to both ends of the coil L of the latching solenoid 1, and a resistor R ₁ and transistors Q ₁ and Q ₂ are connected in series to the power supply Vcc to the coil L.
Capacitor C ₁ is connected in parallel to the Q _2. Coil L
Is input to the amplifier 3 via a limiter including diodes D ₁ and D ₂ , and the output voltage is input to the comparator 4. The other input of the comparator 4 has a power supply Vc
The c and the resistor R ₂ divided reference voltage by a semi-fixed resistor R ₃ is applied.

Reference numeral 5 denotes a microcomputer (CPU) that operates according to a predetermined program, outputs a valve opening control signal or a valve closing control signal to the valve driving circuit 2 in response to an external signal, and outputs transistors Q ₁ and Q Outputs a detection request signal to ₂ . The detection request signal is also input to the delay circuit 6, and the delay output is supplied to the D input of the latch circuit 7 composed of a D flip-flop. Further, the output of the comparator 4 is supplied to the CK (clock) input of the latch circuit 7. Then, the Q output of the latch circuit 7 is input to the CPU 5 as an answerback signal, whereby the CPU 5 determines whether the valve is open or closed.

In the above configuration, the operation will be described with reference to the flowchart showing the work executed by the CPU 5 shown in FIG. 4 and the waveform diagrams of each part in FIGS. 5 (a) to 5 (j).

The CPU 5 outputs a valve opening control signal (FIG. 5A) or a valve closing control signal (FIG. 5B) to the valve drive circuit 2 in the first step S1. Which control signal is output is determined by the CPU 5 based on a signal input from the outside. Now, it is assumed that the gas cutoff valve A is in the valve open state, and the CPU 5 outputs a valve closing control signal (FIG. 5A). CPU5
Is output to the valve drive circuit 2, and in response to this, the valve drive circuit 2 sets the output terminal c to the H level and the output terminal d to the L level, and outputs the signal to the coil L of the latching solenoid 1. On the other hand, a DC valve closing drive current (FIG. 5 (c)) flows in the direction from the output terminal c to the output terminal d for a predetermined time. The movable piece 1 ₁ as described above by is driven gas cutoff valve A is the valve closed state (FIG. 5 (e)).

Next, proceeding to step S2, the CPU 5 outputs a detection request signal for a predetermined time (FIG. 5 (f)), and turns on the transistors Q ₁ and Q ₂ . As a result, a detection voltage is applied to the coil L from the power supply Vcc, the output voltage of the coil L is amplified by the amplifier 3, and the amplified output (FIG. 5 (g)) is input to the comparator 4. The output of the amplifier 3 falls by the time constant of the inductance and resistance R ₁ of the coil L. Therefore comparator 4 compares the voltage with a reference voltage of the coil L, the output of the coil L comparators in greater period t ₁ the voltage is the reference voltage of 4 is inverted to H level (FIG. 5 (h)). On the other hand, the detection request signal is delayed by a predetermined time t ₀ by the delay circuit 6 (FIG. 5 (i)) and supplied to the D input of the latch circuit 7. The latch circuit 7 uses the delay output and the comparator output supplied to the D input and the CK input, respectively.
The polarity of the output is determined.

That is, as described above, the inductance of the coil L when the shut-off valve A is closed becomes larger than the inductance when the valve is opened. Therefore, the falling time constant when the detection request signal is supplied is larger when the valve is closed than when the valve is open, and the output current of the coil L is greater when the valve is closed as shown in FIG. 5 (g). by flow over a long period of time from when the valve is open, a period t ₁ of the H level becomes longer toward the valve closing as the output of the comparator 4 is also FIG. 5 (h).

On the other hand, the output from the delay circuit 6 takes a predetermined time from the detection request signal as shown in FIG. 5 (i) regardless of whether the valve is open or closed.
Since t _{0 is} delayed, the Q output of the latch circuit 7 becomes H level when t ₁ > t ₀ (when the valve is changed from the valve open state to the valve closed state) as shown in FIG. the L level when the ₁ <t ₀ (when it is the valve open state from a valve closed).

In the above configuration, without providing the delay circuit 6 separately, after outputting the detection request signal, a predetermined time is measured by a timer or the like provided in the CPU, and the signal after the measurement is directly supplied from the CPU 5 to the latch circuit 7 as a delay signal. May be.

Further, the function of the latch circuit 7 (D flip-flop) is changed to CP
U5 may do so, in which case the latch circuit 7
Can be omitted.

As is clear from the above description of the operation, the transistors Q ₁ and Q ₂ , the comparator 4 as a comparing means,
A delay circuit 6 as a delay means, a latch circuit 7 as a latch means, and the like, change the operation state of the solenoid 1 depending on the duration of a voltage generated across the coil L of the solenoid 1 when a detection signal is supplied to the coil L. It constitutes a detecting means X for detecting.

〔effect〕

As described above, according to the present invention, the inductance of the coil differs depending on the first or second operation state of the solenoid 1, and the duration of the voltage generated at both ends of the coil changes depending on the operation state. A detection signal is sent to the coil, and the operating state of the solenoid is detected based on the duration of the voltage generated at both ends of the voltage coil. Each state of opening and closing of the valve can be detected in a short time, and can be realized with a simple configuration.

In particular, in order to perform state detection according to the length of the duration,
The voltage generated at both ends of the solenoid coil when the detection signal is passed is compared with the reference voltage, and the voltage detected at both ends exceeds the reference voltage. Since signals corresponding to suction and non-suction of the movable piece are latched and output, these can be used as answer signals as they are.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a solenoid operating state detecting device according to the present invention, FIG. 2 is a circuit block diagram showing one embodiment of a solenoid operating state detecting device according to the present invention, and FIG. FIG. 4 is an explanatory diagram for explaining the principle of operation of the solenoid, FIG. 4 is a flowchart showing work performed by the CPU in FIG. 2, and FIG. 5 is a diagram showing waveforms of various parts in FIG. 1 ... (latching) solenoid, 1 '... movable piece, 2
…… Valve drive circuit, 5a …… CPU (detection signal output means), 4
... Comparator (comparison means), 6... Delay circuit (delay means), 7... Latch circuit (detection means), L... Coil, A.

Claims (2)

(57) [Claims] The movable piece of the solenoid is moved from a first state to a second state.
Or a second driving current for driving from the second state to the first state through the coil of the solenoid, and detecting the operating state of the solenoid thereafter. In the above, after the first or second drive current is passed through the coil of the solenoid, detection signal output means for outputting a detection signal to be passed through the coil of the solenoid, and both ends of the coil of the solenoid when the detection signal is passed Detecting means for detecting the operating state of the solenoid according to the duration of the voltage generated in the solenoid. 2. A comparison means for comparing a voltage generated at both ends of a solenoid coil when the detection signal flows with a reference voltage, and detecting a period in which the voltage at both ends exceeds the reference voltage. A delay means for delaying the detection signal by a predetermined time and outputting the detection signal; and the detection signal delayed by the delay means and the output of the comparison means being present at the same time. The operating state detecting device for a solenoid according to claim 1, further comprising: latch means for latching and outputting signals corresponding to the non-sucking state of the movable piece.