JP2695691B2 - How to check solenoid operation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for checking the operation of solenoids such as various electromagnetic valves and electromagnetic plungers.

[Conventional technology]

For example, in an electromagnetic valve as shown in FIG. 17, a spool 3 is slidably provided in a slide hole 2 formed in a body 1 and springs 6 and 7 provided in spring chambers 4 and 5 on both sides thereof. The spool 3 is held at a valve-closed position (position for shutting off the gap between the inlet port 8 and the outlet port 9) as shown in the figure, and a solenoid 10 fixed at one end of the body 1 is energized by energizing the coil 11. Then, according to the magnitude of the exciting current, the movable iron core 12 moves leftward due to the attraction force between the movable iron core 12 and a fixed iron core (not shown), and the push rod 13 moves the spool 3 to the left. The valve is opened to open the space between the outlet ports 9.

FIG. 18 shows the reaction force of the spring 6 in this case (solid line a).
And the relationship between the force obtained by adding the fluid force thereto (dot-dash line b) and the output of the solenoid 10 (solid line c).

However, when the spool 3 causes a sticking phenomenon due to foreign matter clogging or the like, or the movable iron core 12 of the solenoid 10 comes into close contact with the sliding sleeve, the exciting current for obtaining the solenoid output indicated by the solid line c at the fully closed position is generated. Even if it is supplied to the coil 11, even if the movable core 12 stops moving to the left or the exciting current is reduced so as to reduce the solenoid output by ΔF (= spring force + fluid force) at the fully closed position, the movable core
12 may not be able to leave the adsorption position.

Conventionally, as a method of checking the operating state of such a solenoid, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-265504, an ON operation is detected from a difference in a current response waveform due to a moving state of a movable iron core in the solenoid. Methods are known.

Briefly describing this method, as shown in FIG. 19, a current detection resistor 15 is connected in series to a solenoid coil 11, and a switch 17 is turned on from a power supply 16 to the series circuit, and a current flows. The magnitude of the exciting current flowing through the coil 11 is the resistance
The detected voltage e is detected by converting the voltage into a voltage by the method 15. The response waveform of the detected voltage e is different depending on whether the movable core moves or not.

That is, when the movable iron core moves and the solenoid operates normally, as shown by a solid line in FIG.
When the movable iron core does not move and is not normal, a response waveform without a drop is obtained as indicated by a dashed line.

Therefore, the detected voltage e is amplified by the amplifier 18, the peak value is held by the peak hold circuit 19, and the new detected value is compared with the new detected value. 20 output is inverted to “H”.

When the switch 17 is turned ON, the output of the comparator 21 which becomes "H" as shown in FIG. 20 (A) is ANDed by the AND circuit 22, and a pulse-like output as shown in FIG. Out is obtained. This output is not obtained during abnormal operation.

The operating state of the solenoid can be determined from the output Out.

As described above, many other devices that determine whether the movable iron core of the solenoid moves or not based on a difference in response waveform of current or voltage are disclosed.

As other solenoid operation checking methods, many methods have been proposed in which a mechanical limit switch is incorporated in the solenoid, or a non-contact type proximity switch or a potentiometer is incorporated, and a check is performed based on a detection signal. I have.

[Problems to be solved by the invention]

However, in the conventional method of checking the operation of the solenoid, in the former method, it is possible to judge only at the moment of switching, and to confirm whether or not the noise has occurred, it is necessary to re-operate. It was not possible because the actuator was moved.

Also, the reliability of the check results was low. Especially,
In the case of a so-called shockless solenoid valve in which the movable iron core is hardly moved by oil immersion, the movement of the movable iron core is slow, so that a large difference in response waveforms does not appear, so that there is a problem in the reliability of discrimination.

Although the latter has certainty, the mechanical structure is generally complicated, and extra space is required to store the switches and the like, and the mechanical type has a problem in durability.

The present invention has been made in view of such a conventional problem. After the solenoid is operated, the operating state can be checked at any time as needed, the reliability of the check result is high, and the mechanical It is another object of the present invention to eliminate the necessity of incorporating a suitable switch or the like in the solenoid.

[Means for solving the problem]

According to the present invention, in order to achieve the above object, a current detecting resistor is connected in series to a solenoid coil, and a diode is connected in parallel with the series circuit. Movable by detecting the amount of change in the response waveform of the current flowing through the coil detected by the current detection resistor and demagnetizing by cutting off the power supply to the coil for a short time width that does not move. An operation check method of a solenoid for detecting a position of an iron core is provided.

The amount of change in the response waveform of the current flowing through the coil may be detected based on the waveform change rate, that is, the amount of change per unit time.

Further, the change amount of the response waveform may be detected when the response waveform falls due to demagnetization or when the response waveform after demagnetization rises again.

(Operation)

If the method of checking the operation of the solenoid according to the present invention is applied, after the solenoid is turned on, demagnetization is performed for a time width during which the movable iron core of the pulsed solenoid hardly moves,
From the difference in response current waveform due to the difference in solenoid inductance depending on the position of the movable core, determine whether the movable core is at a predetermined position (ON adsorption position, OFF release position, or intermediate position due to some trouble). Can be.

Then, after the solenoid is turned on (the operation is generally completed within 0.1 seconds), the operation check can be performed at any time, so that the reliability is high and the monitoring from the controller side is easy.

In addition, since there is no need to incorporate a mechanical switch or the like in the solenoid, there is no space problem or durability problem.

〔Example〕

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

FIG. 1 is a block diagram of a solenoid operated check device according to a first embodiment of the present invention, and portions corresponding to FIG. 19 are denoted by the same reference numerals.

First, the configuration will be described.
A current detection resistor 15 is connected in series to the power supply, and a diode 25 is connected in parallel to the series circuit.
A current can be supplied to the series circuit of the coil 11 and the resistor 15 through the capacitor 27 (at this time, the diode 25 is reverse-biased and non-conducting). Energy by diode
The current is kept flowing through the coil 11 and the resistor 15 through 25.

The switch 27 is a controlled switch such as a relay switch or an electronic switch, and is turned on / off by a switch control unit 26 in accordance with the presence / absence of an ON command and an OFF signal.

Further, a timer 28 started by an ON command, and a gate circuit 2 for receiving a check command after the set time of the timer.
9 and a pulse generator 30 for generating a pulse of an OFF signal in accordance with a check command passed through the gate circuit 29.

Further, an amplifier 18 for amplifying the terminal voltage e of the resistor 15 that occurs in accordance with the magnitude of the exciting current flowing through the coil 11, the two hold for holding respectively the output voltage e ₁ during the rise time and the fall of the OFF signal Circuits 31, 32 and inverter 3
4, a differential amplifier 35 that outputs a voltage signal ec according to the difference between the hold outputs eu and ed of the hold circuits 31, 32, and compares the level of the voltage signal ec with a reference value es to detect the movable core of the solenoid. A determination unit 36 for determining a position is provided.

This embodiment is an example of a solenoid on-action check device, and the solenoid 10 is excited as shown in FIG.
This is a device for determining whether or not the movable iron core 12 has reached a suction position where the movable iron core 12 is sucked to the fixed iron core.

The operation of this embodiment will be described with reference to the time chart of FIG.

First, when the ON command for operating the solenoid is set to "H" as shown in FIG. 2A at the time point a in FIG. 2, the switch control unit 26 to which the command is inputted turns on the switch 27 and thereby the DC power supply. An exciting current starts flowing from the coil 16 to the coil 11, and a voltage e corresponding to the current value is generated across the resistor 15.

The output voltage e _{1 obtained} by amplifying the voltage e by the amplifier 18 is
It changes as shown in FIG.

On the other hand, it is activated Yotsute timer 28 is turned ON command, after the timer set time TM1 (to set longer than the time required for the voltage e ₁ is saturated), the output as shown in FIG. (C) is It becomes “H”.

As a result, the gate circuit 29 opens the gate, receives and outputs a check command of a predetermined time width TM2, and starts the pulse generator 30 at the rising point b of the check command,
An OFF signal having a pulse width TM3 is generated as shown in FIG.

The pulse width TM3 of the OFF signal is set to such a short time width that the movable iron core hardly moves even if the power supply to the coil 11 is cut off and the solenoid is demagnetized.

Further, the excisional hold circuits 31 and 32 simultaneously rise time b of a checking instruction to initiate data capture, to hold voltage e ₁ of the time the hold circuit 31 at the rise of the OFF signal pulse. Was but connexion, hold output eu of the hold circuit 31 becomes the saturation level eu ₀ as shown in FIG. 2 (f).

When the OFF signal is output from the pulse generator 30 (becomes “H”), the switch control circuit 2 is turned on for the duration of the pulse width TM3.
Since 6 turns OFF the switch 27, so the current flowing through the coil 11 decreases rapidly to become only the holding current by its own stored energy, the detected voltage e ₁ corresponding to the current value shown in FIG. 2 (b) To decline.

When the time OFF signal at the time c after TM3 is set to "L", will again switch 27 is ON, the current flowing through the coil 11 is returned to the increases and eventually the original state again, the detected voltage e ₁ is also increased Return to saturation level.

The output of the inverter 34 at the falling edge of the OFF signal becomes "1", in order to hold the detected voltage e ₁ at that time to hold circuit 32, hold output ed of the hold circuit 32
Is the minimum level ed ₀ at the time of demagnetization as shown in FIG.
become.

Therefore, the output ec of the differential amplifier 35 thereafter becomes ec =
eu−ed = eu ₀ −ed ₀ and the result is as shown in FIG.

Then, the determination unit 36 compares the difference voltage ec with the reference value es to determine the position of the movable iron core of the solenoid.

At this time, as shown on the normal side in FIG. 2 (nu), if the movable iron core operates normally and is in the suction position, the level of the differential voltage ec is the reference as shown on the normal side in FIG. The value becomes lower than the value es (ec <es), and the determination unit 36 does not output the abnormality detection signal as shown on the normal side in FIG. Note that T1 and T2 in FIG. 3 (n) are time lags of the operation of the movable core.

If the movable iron core does not operate normally and remains at the initial position, as shown on the abnormal side in FIG. The level of ec becomes higher than the reference value es (ec ≧ es), and the judging section 36 outputs a pulse-like abnormality detection signal as shown on the abnormal side in FIG.

Thereafter, when the check command is turned off at the time point d, the hold circuits 31, 32 are reset, and eu, ed, and ec are all 0.
And wait for the next check command.

Then, when the check command is input again at time point e,
The demagnetization is performed between the time points ef and the determination is performed between the time points fg.

In this way, the operating state can be checked any number of times during operation of the solenoid.

In the above embodiment, the timer 28 is immediately turned on by the ON command.
The start has been to open the gate circuit 29 after the setting time TM1, the timer when monitoring the detected voltage e ₁ of the current flowing through the ON command after the coil 11, it reaches a preset value 28 may be activated.

When the inductance L of the coil 11 is large,
It is more reliable to start the timer based on the actual current as described above than to set the time TM1 from the start of energization. In that case, the timer setting time TM1 may be zero.

By the way, when the solenoid is excited, its movable iron core is attracted to the fixed iron core (pole face), and FIG. 17 and FIG.
As described with reference to Fig. 18, it moves while pushing the spool etc. against the spring force + fluid force, and is attracted to the fixed iron core. In the attracted state, to maintain that state, the normal solenoid output Is much larger than the spring force plus the fluid force.

Therefore, even if the current flowing through the coil 11 decreases due to the short-time demagnetization, the movable core maintains the attracted position as long as the solenoid output does not fall below the spring force + fluid force. Alternatively, if there is no problem in the whole system even if the adsorption is momentarily released, the pulse width TM3 of the OFF signal needs to be set to fall within this range.

FIGS. 3 (a) and 3 (b) are waveform diagrams showing the response of the current flowing through the coil 11 due to the demagnetization of the pulse width TM3, that is, the voltage response waveform detected by the resistance, depending on the position of the movable iron core.

The inductance of the coil 11 is smallest when the movable core is at the initial position (the position farthest from the fixed core), and is largest when the movable core is at the adsorption position (the position in close contact with the fixed core). As shown in the figure, it changes depending on the position of the movable iron core.

The amount of change in the voltage waveform during demagnetization (the amount of dip) differs depending on the inductance. When the movable core is at the initial position, the inductance is small, and as shown in FIG. , The amount of drop is small because the inductance is large.

Therefore, the difference voltage ec = eu−ed corresponding to this change amount
Is detected and compared with the reference value es, it is possible to determine where the movable iron core is.

Although the example of the binary determination has been described, if the difference voltage ec is compared with a plurality of reference values having different levels, the position of the movable iron core in a plurality of stages can be detected, and the resolution of the position detection is improved. And the accuracy is improved, and the degree of abnormality or normality can be detected.

Further, if the difference voltage ec is detected steplessly, the position of the movable core can be continuously measured.

FIG. 4 is a block diagram similar to FIG. 1 showing a second embodiment of the present invention.

In this embodiment, a hold circuit 33 for correcting the reference value es and a correction circuit 37 are additionally provided to the solenoid operation check device shown in FIG.

This is due to coil temperature rise and fluctuations in power supply voltage.
This is to correct the reference value es in accordance with the change in the 0% current value and obtain a correct detection point.

The hold circuit 33 is connected to the DC power supply 16 when the switch 27 is ON.
Enter the supply voltage E ₀ of starts data capture is excisional at the rising edge of a checking command, the pulse generator
And hold the input data that is, the voltage E ₀ at the rising edge of the OFF signal from 30, and outputs to the correcting circuit 37.

At the same time, the hold value eu by the hold circuit 31
(A voltage corresponding to a current value flowing through the coil 11 in a steady state after the solenoid is operated) is also input to the correction circuit 37.

Correction circuit 37, the reference value according to the value of these E ₀ and eu
es is corrected and sent to the determination unit 36.

The response of the current flowing through the coil 11 when the switch 27 is turned on is represented by the following equation.

R: the internal resistance of the coil 11 + the resistance value of the resistor 15 L: the inductance of the coil 11 Therefore, the power supply voltage E ₀ immediately before the interruption of the coil current
And the voltage eu corresponding to the steady-state current I at that time is held, so that the value of R is known by R = E ₀ / I, and the reference value es can be corrected in accordance with their fluctuation. .

With this correction, the accuracy of the position determination of the movable iron core based on the difference voltage ec by the determination unit 36 can be improved.

FIG. 5 is a block diagram of a third embodiment using a one-chip microcomputer (hereinafter abbreviated as "microcomputer"), and portions corresponding to those in FIG. 1 are denoted by the same reference numerals. Is omitted. FIG. 6 is a flowchart of the processing by the microcomputer 40.

The microcomputer 40 inputs an ON command and a check command to control ON / OFF of a switch (SW) 27, and outputs an output voltage e ₁ of the amplifier 18 (a voltage corresponding to a current value flowing through the coil 11) to the content A. It is converted to a digital value by the / D converter and checked.
When a malfunction of the solenoid is detected, an abnormality detection signal is output.

In this example, since the external sequencer manages the timing of the ON command and the check command, no interlock means is required between them.

The process by the microcomputer 40 will be described with reference to FIG. 6. When this routine starts, the switch 27 is turned on after waiting for the input of an ON command, and the exciting current flows through the coil 11. After that, 100μ corresponding to the time required to operate the solenoid
After S elapses, it waits for a check command input.

If there is no ON command before the check command is input, the switch 27 is turned OFF to cut off the power supply to the coil 11, and waits for the next ON command.

When a check command is input after the elapse of 100 μS, an OFF pulse having a predetermined short pulse width is generated, and the switch 27 is turned OFF only during that time.

Then, hold the A / D conversion value of the output voltage e ₁ from rising by the amplifier 18 of the OFF pulse, the held value as the eu, the voltage e ₁ at the fall of the OFF pulse A / D
The converted value is held, and the held value is set as ed.

Next, ec = eu-ed is calculated, and ec is compared with a reference value es. If ec> es, it is determined that the movable iron core has not moved, and an abnormality detection signal is output. Nothing is output if ec ≦ es.

After that, wait for the check command to disappear, reset the hold value eu, ed, check again for the ON command, wait for the next check command if it exists, and turn off the switch 27 when the ON command disappears. Wait for the next ON command.

Of course, instead of the microcomputer 40, it is also possible to configure a wired logic circuit using digital elements.

FIG. 7 is a block diagram similar to FIG. 1 showing a fourth embodiment of the present invention, and portions corresponding to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

In this embodiment, after the solenoid is turned on, an operation check is automatically and periodically performed with a predetermined time width, and the result is output in an analog amount.

In FIG. 7, the difference from the first embodiment of FIG.
A pulse generator (PG) 41 for generating a check command pulse is provided in place of the gate circuit 29 to eliminate the need for inputting a check command from outside, and a movable core position calculating section 42 is provided in place of the determination section 36. The only difference is that the movable core position information is output by analog signals.

The operation of the fourth embodiment will be described with reference to the time chart of FIG.

When an ON command is input from the outside as shown in FIG. 8 (A), the switch control unit 26 turns on the switch 27, and
At the same time as energizing the coil 11 of the solenoid from 16 is started, the timer 28 is started.

The timer 28 activates the pulse generator 41 when the set time TM1 has elapsed. As shown in FIG. 8 (c), the pulse generator 41 generates a check command pulse having a pulse width of TM2 and a cycle of TM20.

At the rise of this check command pulse, each hold circuit
The pulse generator 30 is started at the same time that the data fetching is started by setting 31 and 32.

As a result, the pulse generator 30 generates an OFF signal pulse having a pulse width of TM3 and a period of TM20, and the switch control circuit 2
6 turns off the switch 27 only during the period TM3 to demagnetize the solenoid.

At this time, although detecting a response waveform of the current flowing through the coil 11 as a resistor 15 and by connexion voltage e ₁ to the amplifier 18, the waveform is as shown in Figure 8 (b). Switch 27 off
The voltage e ₁ immediately before turning on is held by a hold circuit 31 (the value is eu), and the voltage e ₁ immediately before turning on again is held by a hold circuit 32 (the hold value is ed). Do).

The difference ec between each of the hold values eu and ed is calculated by the differential amplifier 35, and the difference ec is calculated by the movable core position calculation unit 42,
The movable iron core position information ea as shown in FIG. 8 (e) is calculated and output.

At the falling edge of the check command pulse from the pulse generator 41, the hold circuits 31, 32 are reset and one check is completed, but since the pulse generator 41 periodically generates the check command pulse in the period TM20, Immediately, the next check is performed, and the movable core position information ea is periodically output.

FIG. 9 is a block diagram similar to FIG. 7 showing a fifth embodiment of the present invention. Parts corresponding to those in FIGS. 1 and 7 are denoted by the same reference numerals, and their description. Is omitted.

In this embodiment, a main switch 43 for turning on / off the solenoid and a demagnetizing switch (normally closed switch) 27 'for operating check are separately provided so that they can be used in a conventional simple system.

The difference between the fifth embodiment and the fourth embodiment of FIG.
In addition to the points described above, only the point that the switch control unit 26 is not required and the point that the determination unit 36 is provided in place of the movable core position calculation unit 42 as in the first embodiment.

According to the fifth embodiment, an external ON command is unnecessary, and when the main switch 43 is turned ON, the coil 11 is energized to operate the solenoid, and after a predetermined time TM1, a predetermined period (fourth embodiment) When the operation check is performed periodically in the same manner as in the example TM20) and it is determined that there is an abnormality (non-operation) in the position of the movable iron core, an abnormality detection signal is output.

FIG. 10 is a block diagram showing a sixth embodiment of the present invention, in which parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and their description is omitted.

The difference between the sixth embodiment and the first embodiment shown in FIG.
The timer 28 and the gate circuit 29 are removed, and a pulse generator (PG) 44 for generating a pulse for detection of the pulse width TM4 is provided. The OFF signal generated by the pulse generator 30 is inverted and the hold signal of the hold circuit 31 is inverted. And an inverter 45 that inverts the detection pulse generated by the pulse generator 44 and generates a hold signal for the hold circuit 32.

In this embodiment, a coil current waveform at the time of re-input after demagnetization of the solenoid is used, and a rising waveform after demagnetization within a predetermined time width (TM3) is checked.

The operation will be described with reference to the time chart of FIG. 11.After the switch 27 is turned on by the ON command to operate the solenoid, when the check command is input, the pulse generator 30 turns off the pulse width TM3. A signal is generated, and the switch control circuit 26 turns off the switch 27 for that period to demagnetize the solenoid, and after a period TM3, turns on the switch 27 again.

Was but connexion, the output voltage e ₁ of the waveform of the amplifier 18 corresponding to the waveform of the current flowing through the coil 11 is as shown in FIG. 11 (b).

Then, the lowermost value of the hold circuit 31 at the fall of the voltage e ₁ OFF signal to the hold as shown in FIG. (B)
eu.

Also, the pulse generator 44 generates a pulse for detection of the pulse width TM4 from that time, and the hold circuit
32 and ed to hold the voltage e ₁ of the rising as shown in FIG. (C).

Then, the differential amplifier 35 outputs a signal ec shown in FIG. 4D at a level corresponding to the difference between the voltages eu and ed, and the determination unit compares it with the reference value es, and ec> es. And outputs a high-level abnormality detection signal as shown in FIG.

This embodiment is suitable for a case where the fluctuation of the coil resistance and the power supply voltage is small. In this case, similarly to the second embodiment of FIG. 4, by correcting the reference value es,
Accuracy can be increased.

FIG. 12 is a block diagram showing a seventh embodiment of the present invention, in which parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and their description is omitted.

In this embodiment, the OFF signal through the normally closed switch 51 a checking instruction, after the solenoid is turned OFF as shown in FIG. 13 (b), the output voltage e ₁ of the amplifier 18 is the figure (b)
When lowered to the reference value es ₁ as shown in the I connexion normally closed switch 51 to the output of the comparator 50 and to OFF, and at the same time cycled solenoid, the input voltage e ₁ = es ₁ at that time to a hold circuit 31 Hold.

At the same time, the timer 52 starts, generates a pulse after the set time TM5, and supplies the hold circuit 32 with the rising voltage.
Let e _{1 be held} and be ed.

Signal e differential amplifier 35 according to the difference between the voltage es ₁ and ed
c is output, and the determination unit 36 compares it with the reference value es to determine the position of the movable iron core. If the result is ec> es, an abnormality detection signal is output.

According to this embodiment, the checking accuracy is improved as compared with the sixth embodiment shown in FIG. If you add the reference value es ₁ and es in the correction, it is possible to further improve the accuracy.

I do.

Although the description of each of the above embodiments is based on the detection of a change in the magnitude of the current value within a unit time, the measurement is performed by measuring the inclination as in the eighth embodiment shown in FIG. Is also good.

The operation of the eighth embodiment will be described with reference to the waveform diagram of FIG.

After the switch 27 is turned OFF by a checking command, the output voltage e ₁ of the amplifier 18 is decreased to the reference value es _1, the point of reintroduction of the switch 27 by connexion normally closed switch 51 to the output of the comparator 50 in the OFF state The seventh embodiment (the twelfth embodiment)
FIG.

In the eighth embodiment, the output voltage e ₁ and by connexion constantly differentiated in the differentiation circuit 53 of the amplifier 18, to hold as shown in by connexion FIG. 15 to the peak hold circuit 54 the peak value of the differential signal ey .

The hold value ez compared to determining unit 55 by connexion reference value es _2, and outputs an abnormal detection signal if ez> es _2.

In this example, the current response waveform has the same relationship because it is a first-order lag type.

In this example, the detection is performed when the switch 27 is turned on again. However, the slope of the current response waveform may be checked immediately after demagnetization as in the seventh embodiment.

FIG. 16 is a circuit diagram showing only the vicinity of a portion where a coil 11 is energized according to a ninth embodiment of the present invention.

This embodiment is an example in which the solenoid 27 is normally de-energized when the switch 27 is switched from ON to OFF, and the switching switch 57 is always switched to the varistor 56 side as shown in FIG. During normal ON / OFF by the varistor
The switching switch 57 is switched to the diode 25 side only when the switch 27 is turned off by a check command immediately after demagnetization via the switch 56.

Other configurations and operations may be the same as those in the above-described embodiments, and a description thereof will not be repeated.

〔The invention's effect〕

As described above, according to the present invention, the following effects can be obtained.

(1) The position information of the movable core can be obtained at any time by giving a check command after the solenoid is excited.

(2) It can be constituted by an electronic circuit, and no new parts are required to be attached to the valve.

(3) If the check command is periodically performed based on the ON signal of the solenoid, the position information of the movable iron core can always be obtained.

(4) If the current waveform at the time of solenoid demagnetization is to be checked, the current waveform is checked during the period of disconnection from the power supply.
Not affected by power ripple.

Therefore, a simple power supply for full-wave rectification can be used as it is, and a filter or the like becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a block diagram of a solenoid operated check device showing a first embodiment of the present invention, FIG. 2 is a time chart for explaining the operation thereof, and FIGS. FIG. 4 is a waveform diagram showing a difference between response waveforms, (c) is a diagram showing a relationship between a movable iron core position and an inductance of a solenoid coil, and FIG. 4 is a diagram similar to FIG. 1 showing a second embodiment of the present invention. FIG. 5 is a block diagram of an apparatus using a micro computer according to a third embodiment of the present invention, FIG. 6 is a flowchart of processing by the micro computer, and FIG. 7 is a fourth embodiment of the present invention. FIG. 8 is a block diagram similar to FIG. 1 showing an example, FIG. 8 is a time chart for explaining the operation thereof, FIG. 9 is a block diagram similar to FIG. 7 showing a fifth embodiment of the present invention, FIG. The figure shows this FIG. 11 is a block diagram similar to FIG. 1 showing a sixth embodiment of the present invention, FIG. 11 is a time chart for explaining the operation thereof, and FIG. 12 is a block diagram similar to FIG. 1 showing a seventh embodiment of the present invention. FIG. 13, FIG. 13 is a waveform diagram for explaining the operation thereof, FIG. 14 is a block diagram showing an eighth embodiment of the present invention, FIG. 15 is a waveform diagram for explaining the operation thereof, and FIG. FIG. 17 is a circuit diagram showing only the vicinity of a portion where a coil is energized according to the ninth embodiment; FIG. 17 is a longitudinal sectional view showing an example of a solenoid valve using a solenoid; FIG. 18 is a diagram for explaining its operation; FIG. 19 is a block diagram showing an example of a conventional device for checking the operation of a solenoid, and FIG. 20 is a time chart for explaining its operation. 10: Solenoid, 11: Coil 12: Movable iron core, 13: Push rod 15: Resistor for current detection, 16: DC power supply 18: Amplifier, 25: Diode 26: Switch control unit, 27 ... … Switch 27 ′… Demagnetizing switch, 28,52… Timer 29… Gate circuit 30,41,44… Pulse generator 31,32,33… Hold circuit 35… Differential amplifier, 36… Judgment Unit 37 Correction circuit 40 One-chip microcomputer 42 Moving core position calculator 43 Main switch 50 Comparator 51 Normally closed switch 53 Differentiator circuit 54 Peak hold circuit 56 …… varistor, 57 …… Switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuyuki Kihara 2-16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Inc. (72) Inventor Kosuke Hatanaka 2--16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Co., Ltd. (72) Inventor Akio Mito 2-16-46 Minami Kamata, Ota-ku, Tokyo Inside Tokimec Co., Ltd. (56) References JP-A-1-265504 (JP, A)

Claims (4)

(57) [Claims] 1. A current detecting resistor is connected in series to a coil of a solenoid, and a diode is connected in parallel with the series circuit. A short enough that the movable iron core hardly moves after the solenoid is turned on. The position of the movable iron core is determined by cutting off the power supply to the coil for a long time width, demagnetizing the coil, and detecting the amount of change in the response waveform of the current flowing through the coil detected by the current detection resistor. A method for checking the operation of a solenoid, characterized by detecting. 2. The solenoid operating check method according to claim 1, wherein a change amount of a response waveform of a current flowing through said coil is detected by a waveform change rate, that is, a change amount per unit time. Operating check method. 3. The method according to claim 1, wherein the detection of the change in the response waveform of the current flowing through the coil is performed when the response waveform falls due to the demagnetization. 4. The method according to claim 1, wherein the detection of the change in the response waveform of the current flowing through the coil is performed when the response waveform re-rises after the degaussing.