JPH01265504A - Device for detecting operation of solenoid - Google Patents

Abstract

PURPOSE:To electrically detect the working condition of a solenoid by a method wherein the working condition of the solenoid is detected based on the characteristic discharge waveform of the energy stored in a solenoid coil. CONSTITUTION:When the conducting current of a solenoid coil is interrupted, first, the discharge waveform of the energy stored in the coil MB is detected by a discharge waveform detector MC. The state of characteristic variation of the discharge waveform is detected by a discharge waveform variation state detector MD, and the working state of the solenoid MA is detected by a working state detector ME based on the above-mentioned state of characteristic variation. Accordingly, when there is a change in impedance generated by the working of the solenoid MA on the discharge waveform of the coil MB, first, the change based on the impedance variation is detected, and then the working state of the solenoid MA is detected from the above-mentioned variation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting the operating state of a solenoid, and more particularly to a device for detecting the operating state when the current flowing to the solenoid is cut off.

[Prior Art] Conventionally, as a device for detecting the operating state of a solenoid,
As shown below, a technique for detecting the operating state when the solenoid is energized and a technique for detecting the operating state when the solenoid is energized have been developed.

(I) Technology when energizing is turned on This technology controls the current flowing to the solenoid by detecting that the plunger, spool, etc. have actually operated when the solenoid coil is energized. . This detection of whether or not it is actually activated is disclosed in Japanese Patent Application Laid-open No. 62-167985 and Japanese Patent Publication No. 62-24921.
The means disclosed in Japanese Utility Model Publication No. 62-9682 are used. That is, the operating state of the plunger or the like is detected from a characteristic change state of the supplied current, for example, a state of decrease in the current, and it is detected that the solenoid has actually operated.

(I[) Technology when the energization is turned off: When the energization is turned off, the operation of the plunger, etc. is detected by a pressure sensor, etc., and the actual operation of the solenoid is detected.

[Problems to be Solved by the Invention] However, in the conventional technology, as shown below, the only way to detect the actual operating state when the solenoid is energized is to use a dedicated sensor, and the parts There were problems that resulted in an increase in the number of devices, a decrease in reliability, and a delay in detection.

In other words, the technique (f) above detects the actual operating state of the solenoid based on the changing state of the energizing current, so it was not possible to detect the operating state of the solenoid after the energizing current was cut off. .

Further, the technique described in (I[) requires actually installing a dedicated sensor, and includes the following problems. ■A dedicated sensor and wiring are required. ■The sensor must be installed with high precision, which increases the number of man-hours required for installation. ■
Reliability decreases as the number of parts increases. ■Since the pressure sensor outputs a signal when the solenoid actually completes operation, it may not be usable for control where delay time is an issue.

An object of the present invention is to detect the actual operating state of a solenoid with a simple configuration when the energizing current of the solenoid is interrupted by solving the above problems.

[Means for Solving the Problems] As a means for achieving the above object, the solenoid operation detection device of the present invention includes a solenoid that converts electrical energy into mechanical energy, as illustrated in FIG. A device that detects the operating state of a solenoid MA when the current flowing to the MA is cut off, and includes a solenoid coil MB.
discharge waveform detection means MC for detecting a discharge waveform of energy stored in the discharge waveform; discharge waveform change state detection means MD for detecting a characteristic change state of the discharge waveform due to a change in the impedance of the solenoid coil MB; The present invention is characterized by comprising an operating state detection means ME that detects the operating state of the solenoid MA based on the changing state.

[Operation] The solenoid operation detection device of the present invention detects the solenoid coil M when the current flowing to the solenoid coil MB is cut off.
First, the discharge waveform of the energy stored in B is detected by the discharge waveform detection means MC.

Next, the discharge waveform change state detecting means MD detects the characteristic change state of the discharge waveform, and the operating state detecting means ME detects the operating state of the solenoid MA based on this unique change state. Therefore, the solenoid coil M
If the discharge waveform of B includes an impedance change caused by the operation of the solenoid MA, a change based on this impedance change is first detected, and then the operating state of the solenoid MA is detected from this change.

As shown in FIG. 2, the characteristic change state of the discharge waveform due to the impedance change of the solenoid coil MB is indicated by, for example, the state in which the terminal voltage changes during discharge.

(I) State when solenoid is on: ■Starts energizing solenoid coil MB at time TO,
At time T1, it is detected that the solenoid MA is actually turned on from the temporary decrease in the applied current.

(2) After detecting that the Tsuremade MA is actually turned on in (2) above, the terminal voltage of the solenoid coil MB is normally controlled to a value for normal operation.

(II) State when the solenoid is off: ■If the current flowing to the solenoid coil MB is cut off at time T2 from the above-mentioned steady state terminal voltage state,
Depending on the state of solenoid MA, the following discharge waveform occurs.

When the plunger of solenoid MA is restrained and does not move: In this case, as shown in the terminal voltage (A) of solenoid coil MB in Fig. 2, the terminal voltage spikes significantly in the negative direction at time T2. Later, the discharge waveform converges smoothly towards the zero point. That is, solenoid M
When A is inactive, the discharge waveform converges smoothly in this way.

When the plunger of solenoid MA is not restrained: In this case, as shown in the terminal voltage (B) of solenoid coil MB in Fig. 2, after the terminal voltage spikes significantly in the negative direction at time T2, When converging toward the zero point, disturbances occur in the discharge waveform as shown from time T3 to time T4.

That is, if solenoid MA actually operates,
After a unique waveform occurs in the discharge waveform, it rapidly converges to the zero point.

(2) The operating state according to (2) above can be recognized by the waveforms showing other states in FIG.

In other words, the actual turning on and off of the solenoid MA is determined by the state of the human power wave in the waveform representing the operating sound of the solenoid MA in Fig. 2, or the transition of the waveform of the operating state of the solenoid MA, which measures the actual operating state. This can be confirmed depending on the condition.

From the above, it is possible to detect the operation of the solenoid MA since there is a specific change due to a change in impedance when the applied current is interrupted.

[Embodiment] Next, an embodiment of the solenoid operation detection device of the present invention will be described based on FIG. 3 showing the configuration and FIG. 4 showing the operating state thereof.

Solenoid operation detection device 1 of this embodiment shown in FIG.
is a solenoid valve 3 as a solenoid (here, only the coil 5 of the solenoid valve 3 is shown, and the plunger is omitted from illustration)
The operating state of the electromagnetic valve 3 is detected, and an operating state signal indicating whether the solenoid valve 3 is actually on or off is output to its output terminal 7.

The coil 5 of the solenoid valve 3 is connected to a power source 9, and between the coil 5 and the power source 9 is a non-contact switch 11 made of a semiconductor, which detects the current flowing through the coil 5. A current detection resistor 13 for this purpose is interposed in series. A power supply 9 that supplies power to the coil 5 and a switch 1
1 is controlled by a control device not shown here. Note that the control device controls the output voltage v1 of the power source 9 and the on/off state of the non-contact switch 11, as will be described later.

Next, the on-operation detection section 13 that detects that the solenoid valve 3 is actually turned on will be explained. This ON operation detection section 13
Turn on the non-contact switch 11 to apply voltage ■2 (=voltage Vl) to the series circuit of coil 5 and current detection resistor 13.
When energization is applied, a change in the applied current is detected by a change in the voltage V3 across the current detection resistor 13, and it is detected whether the solenoid valve 3 is actually turned on. The on-operation detection section 13 for detecting this on-state has the configuration shown below. An amplifier 15 that amplifies the voltage 3 across the current detection resistor 13, a peak-halt circuit 17 that peak-holds the output of this amplifier 15 and outputs a value slightly smaller than the peak value of the human power value, and adds this peak value. The output of the amplifier 15 is input to the input terminal 19, the output of the amplifier 15 is input to the negative input terminal 21, and the comparator 23 compares the magnitude of the input values of both input terminals 19 and 21. The output of this comparator 23 is input to the input terminal 25. , input terminal 27 of coil 5
is a positive voltage, the output of the comparator 29 which outputs an output value "1" is input to the input terminal 31, and both terminals 25.
It is composed of an AND circuit 33 that performs an AND operation of 31 human power values.

Next, the operating state of the on-operation detection section 13 will be explained based on FIG. 4, which shows the operating state over time.

■Up to time T5: Non-contact switch 11 is turned on,
When voltage V2 is applied to coil 5, the current flowing through coil 5 increases. Reflecting this state of increase, the output of the peak halt circuit 17 increases.

(2) At time T5: When the plunger of the solenoid valve 3 is actuated, the impedance of the coil 5 increases and the energizing current starts to decrease. Therefore, the peak halt value at this time point T5 is held.

■When time T5 has passed: the human power value of the positive input terminal 19 of the comparator 23 is held at the peak hold value,
The negative input terminal 21 begins to decrease in size as the applied current decreases. As a result, the output of the comparator 23 is inverted from the value "zero" to "1". Moreover, since the comparator 29 is outputting a direct "1" here, the AND circuit 330 input terminal 31 has already output a direct "1".
is done manually. Therefore, the AND circuit 33 inverts the value from "zero" to "1" here.

(2) Time T6: When the movement of the plunger of the solenoid valve 3 is completed, the impedance of the coil 5 no longer increases, and as a result, the energizing current starts to increase again. Therefore, at time T6, the conduction current exceeds the peak hold value at time T5, the output of the comparator 23 is reversed from the value "1" to "zero", and the output of the AND circuit 33 is reversed from the value "1" to "zero". do.

Next, the off-operation detection section 40 that detects that the solenoid valve 3 is actually turned off will be explained. This off operation detection section 40
The solenoid valve is activated by detecting that the voltage V2 across the series circuit of the coil 5 and the current detection resistor 13 changes in a specific manner when the non-contact switch 11 is turned on and then turned off. 3 is actually turned off or not. In order to detect this off state, the off operation detection section 40 takes the configuration shown below. The non-contact switch 11 turns from on to off, discharging the energy stored in the coil 5 via the resistor 42 and the Zener diode 44, and increasing the discharge voltage generated at the time of this discharge to a predetermined voltage (this value). (Deleting the following will be described later), the output limiter 46, the amplifier 48 that amplifies the output of the limiter 46, the differentiation circuit 50 that differentiates the output of the amplifier 48, and this differential value is input to the plus input terminal 52. Then, a reference voltage (predetermined fi) is manually input to the negative input terminal 54, and a comparator 56 is used to compare the magnitude of the input values of both input terminals 52 and 54. The output of the comparator 29 described above is manually input to the manual power terminal 62 via the inverter 60, and the AND operation of the manual power values of both terminals 58° and 62 is performed.
It is composed of a D circuit 64.

Next, the operating state of the off-operation detection section/10 will be explained based on FIG. 4.

(2) Time T7: This is the time when the non-contact switch 11 is turned off. At this point, the energy of the coil 5 becomes a spike waveform, and the voltage i=voltage is largely generated in the opposite direction.

(2) From time T7 to time T8: The reverse spike voltage is removed by the limiter 46 to a level below a predetermined voltage, and is amplified by the next amplifier 48. Therefore, until time T8, a constant negative voltage is output from the amplifier 4.

(2) After time T8: When the plunger of the solenoid valve 3 starts operating, the impedance of the coil 5 starts to change accordingly. This change slows down the convergence of the spike voltage in the opposite direction. That is, the slope of the spike waveform becomes gentler.

(2) Time T9: After the change (2) occurs and the movement of the plunger is completed, the impedance change disappears, so the spike waveform rapidly converges toward the zero level. In other words, the waveform that became gentle in ■ becomes steeper here. Thereby, this steep waveform is differentiated by the differentiating circuit 50 and converted into a positive pulse waveform.

(2) After time T9: The output pulse of the differentiating circuit 50 is compared with the reference voltage by the next comparator 56.

If the output pulse is higher than the reference voltage, the comparator 56
outputs the value "1". As a result, comparator 5
6 outputs the value "1" when the spike waveform of the coil 5 is higher than a predetermined voltage and changes rapidly.

■The output of the inverter 60 The inverter 60 has the coil 5
When no positive voltage is applied to the terminal, it outputs the value "1".

■By the above ■ or ■, the AND circuit 58 is connected to the coil 5.
When the comparator 56 outputs the value "1" in a state where no positive voltage is applied to the comparator 56, the value "1" is output. In other words, the non-contact switch 11 changes from "on" to "
When the solenoid valve 3 is turned off and the plunger of the solenoid valve 3 actually operates, the off-operation detection section 40 outputs a value of "1".

The optimum values of the predetermined voltage of the limiter 46, the constant of the differentiating circuit 50, and the reference voltage of the comparator 56 are determined through appropriate experiments depending on the specifications of the solenoid valve 3. For example, measure the spike waveform when the plunger of the solenoid valve 3 is operated freely and when it is restrained so that it does not operate, and set the voltage at which the slope of the waveform becomes gentler when the plunger is restrained to the predetermined voltage of the limiter 46. The reference voltage is set to a voltage that does not output an erroneous signal when the plunger is restrained. Further, the constants of the differentiating circuit 50 are also determined and set to optimum values through experiments.

The output of the ON operation detection section 13 described above is input to the set input terminal of the latch 70, the output of the OFF operation detection section 40 is input to the reset input terminal of the latch 70, and the latch 70 inputs the output to the amplifier. By outputting to the output terminal 7 via the solenoid valve 72, an output signal reflecting the operating state of the electromagnetic valve 3 is outputted from the output terminal 7, as shown below.

■As shown in FIG. 4, the ON operation detection unit 13 indicates the "ON" operation of the solenoid valve 3 (directly "1" is output, and at the time T5 when the set input terminal of the latch 70 is manually applied, the latch 7
An output of 0 becomes the value "1".

■In the above state ■, the value "1" indicating the "off" operation of the solenoid valve 3 is output from the off operation detection section 40, and at the time T9 when the reset input terminal of the latch 70 is manually applied, the output of the latch 70 is as follows. The value becomes "zero".

(2) According to (2) and (2) above, the output terminal 7 outputs a signal with a slope of "1" when the solenoid valve 3 actually operates "on", and outputs a signal with a value of "zero" when the solenoid valve 3 actually operates "off".

As explained above, in this embodiment, the actual "on" operation is detected by the current flowing through the coil 50, and the actual "off" operation is detected based on the characteristic change in the spike waveform when the current flowing through the coil 5 is cut off. Detect actuation. As a result, solenoid valve 3
The actual operating state of the coil 5 can be reliably detected by detecting the current flowing through the coil 5 and the terminal voltage. Therefore, the operating state of the plunger of the solenoid valve 3 can be electrically detected without using a mechanical sensor that directly detects the operation. Installation requires space,
There is no need to consider detection methods, wiring, etc. As a result, with this embodiment, it is possible to freely attach a sensor that detects the operating state without considering the type and position of the solenoid valve, and it is also resistant to noise such as operating noise and vibration, and the number of wires is reduced. It is also possible to provide a good sensor with the minimum necessary amount. In other words, it is easy to install, highly versatile,
This has an extremely excellent effect of being able to easily provide a reliable sensor.

Moreover, the excellent effect of detecting a failure of the solenoid valve and improving the reliability and maintainability of the entire apparatus is achieved. Furthermore, by feeding back the operating state of the electromagnetic valve and using it in a device that controls the operating time and timing, it is possible to achieve an excellent effect of increasing the precision and operating speed of the device.

Note that the present invention is not limited to the above embodiments,
For example, instead of a solenoid valve, it is possible to detect the operating state of any solenoid that converts electrical energy into mechanical energy without changing the gist of the present invention. Further, the circuit configuration for detection may be any circuit configuration as long as it does not change the gist of the present invention.

[Effects of the Invention] The solenoid operation detection 'JAW of the present invention detects the operating state of the solenoid based on the unique discharge waveform of the energy stored in the solenoid coil.

This allows the solenoid to know the operating status of the solenoid.
The operating state of the solenoid can be electrically detected directly by vibration or sound without installing a sensor for detection. Therefore, it is no longer necessary to consider the sensor installation location, installation man-hours, detection delay, space, detection method, sensor-specific electrical wiring, etc. for each individual SoshiMade, making it highly versatile. This has an extremely excellent effect of being able to provide a sensor.

Further, according to the present invention, an excellent effect is achieved in that highly accurate feedback control of the operating time when the applied current is interrupted can be performed extremely easily.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram illustrating the basic configuration of the solenoid operation detection device of the present invention, FIG. 2 is a detailed explanatory diagram of the present invention,
FIG. 3 is a block diagram of one embodiment, and FIG. 4 is a graph showing its operating characteristics. MA-... Solenoid, MB... Solenoid coil,
MC...discharge waveform detection means, MD...discharge waveform change state detection means, ME...operation state detection means, 1...
Solenoid operation detection device, 3... solenoid valve, 5...
Coil, vessel, 46... limiter, 60... inverter, 70... - Latch agent, patent attorney Tsutomu Sadate (and 2 others) No. 1
figure

Claims (1)

[Claims] A device for detecting the operating state of a solenoid when the current flowing to the solenoid that converts electrical energy into mechanical energy is cut off, the device detecting the discharge waveform of energy stored in the solenoid coil. discharge waveform detection means for detecting a characteristic change state of the discharge waveform due to a change in impedance of the solenoid coil; and a discharge waveform change state detection means detecting a characteristic change state of the discharge waveform due to an impedance change of the solenoid coil; 1. A solenoid operation detection device comprising: an operation state detection means for detecting an operation state of a solenoid.