JPS5841651B2 - Electromagnetic solenoid abnormality detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting an abnormality in an electromagnetic solenoid.

Conventionally, if one of the many electromagnetic solenoids used in automatic machines such as packaging machines is blocked by an obstacle or has a wire breakage, or if the core of the electromagnetic solenoid does not return to its original position due to an obstacle, etc. The part related to the electromagnetic solenoid was not working, causing the entire machine to malfunction.

Furthermore, if the operation of the electromagnetic solenoid is prevented by an obstacle, the electromagnetic solenoid may be burnt out due to overcurrent.

An object of the present invention is to prevent malfunctions of automatic machines such as packaging machines by detecting the abnormality when the electromagnetic solenoid is blocked by an obstacle or disconnected. An object of the present invention is to provide an electromagnetic solenoid abnormality detection device.

The present invention will be described below based on an embodiment shown in the drawings.

1 is an electromagnetic solenoid, 2 is an electromagnetic solenoid switch,
Reference numeral 3 denotes a switch having Q detection circuits, and switches 2 and 3 are operated at the same time.

Reference numeral 4 indicates a starting current detection circuit for the electromagnetic solenoid, and reference numeral 5 indicates a timer circuit, which delays the drive signal for the electromagnetic solenoid for a certain period of time.

Reference numeral 6 denotes an AND circuit (AMD circuit), which is configured to AND the signal of the electromagnetic solenoid starting current detection circuit 4 and the signal of the timer circuit 5.

7 is a storage circuit for a starting current signal, and 8 is a NOT circuit.

Reference numeral 9 denotes a logical product circuit (AND circuit), which is designed to logically multiply the signal of the timer circuit 5 and the signal of the NOT circuit 8.

10 is a logical sum circuit (OR circuit), and a logical product circuit (A
The signal from the ND circuit (ND circuit) 6 and the signal from the AND circuit (AND circuit) 9 are logically summed.

14 is an overcurrent warning light, 15 is a disconnection warning light,
18 and 19 are memory circuits.

20 is an electromagnetic operation signal input, and 21 is an electromagnetic valve abnormality signal output.

11 is a diode bridge, which performs full-wave rectification of the current flowing through the electromagnetic solenoid 1.

12 is a resistor, and a photocoupler 13 is connected in parallel.

Diode bridge 11, resistor 12 and photocoupler 13
constitutes the electromagnetic solenoid starting current detection circuit≦.

When the switch 2 is turned on, the electromagnetic solenoid 1 is energized, and since the inductance at startup is small, a large starting current 16 flows through the electromagnetic solenoid.When the electromagnetic solenoid 1 is activated, the inductance increases and the current decreases, resulting in a normal A current flows (see Figure 2).

Furthermore, if the operation of the electromagnetic solenoid 1 is prevented by an obstacle, the inductance does not become constant, so that an overcurrent 17, which is the same as the starting current, flows (see FIG. 3).

When the electromagnetic solenoid 1 operates normally, the starting current is full-wave rectified by the diode bridge 11 and passes through the resistor 12, so that the 0 potential difference between the resistors 120 and 120 becomes zero, and the photocoupler 13 operates to output a signal.

When the electromagnetic solenoid 1 operates normally, the starting current decreases, and therefore the potential difference between both ends of the resistor 12 becomes small, causing the photocoupler 13 to stop operating and stop emitting signals.

The timer circuit 5 receives the solenoid valve operating signal 20 at the same time as the electromagnetic solenoid 1 by the switch 3 which operates at the same time as the switch 2, but the signal output from the timer circuit 5 is delayed for a certain period of time, and the electromagnetic solenoid 1 is activated for a certain period of time. It takes longer than the time it takes for the starting current to decrease.

Therefore, the starting current detection signal enters the AND circuit (AND circuit) 6, and after the starting current detection signal disappears, θ signals enter from the timer circuit 5. Since these signals do not enter at the same time, the AND circuit ( No signal is generated from AND circuit) 6.

In addition, in the AND circuit (AND circuit) 9, the starting current is stored in the starting current storage circuit 7, and a signal is output from the starting current storage circuit 7, but is negated by the NOT circuit (NOT circuit) 8, and the starting current is stored in the AND circuit (AND circuit). No signal enters circuit) 9.

Therefore, a signal is input from the timer circuit 5 to the AND circuit (AND circuit) 9 after a certain period of time after starting the electromagnetic solenoid 10, but since no signal θ is input from the starting current memory circuit 7, the AND circuit (AND circuit) ) No signal is given from 9.

On the other hand, when the operation of the electromagnetic solenoid 1 is prevented by an obstacle, a large current θ similar to the starting current constantly flows through the resistor 12, and the photocoupler 13 constantly generates a signal.

Therefore, the Q9 signal is constantly input from the photocoupler 13 to the AND circuit (AND circuit) 6, and when the signal from the timer circuit 5 is input after a certain period of time, it is ANDed in the AND circuit (AND circuit) 6, and a signal is generated and stored. When stored by the circuit 18, the overcurrent warning light 14 lights up.

At the same time, an OR circuit 10 emits a signal, which turns off the power to automatic machines such as packaging machines.

Further, the AND circuit 9 receives a signal from the timer circuit 5 after a certain period of time has elapsed after starting the electromagnetic solenoid 1; No signal is output from the product circuit 9.

Therefore, the disconnection warning light 15 is turned off.

In addition, if the coil of electromagnetic solenoid 1 is disconnected, or if the core of electromagnetic solenoid 1 has not returned due to an obstacle, etc., even if switches 2 and 3 are turned on, the starting current detection circuit 44 will detect Does not generate a signal.

Therefore, there is a signal from the AND circuit (AND circuit) 6, but there is no starting current detection signal from the AND circuit (AND circuit) 9, which is the starting current memory circuit. The or signal is negated by the negation circuit 8, a signal is input, and after a certain period of time after the start switch is turned on, a signal from the timer circuit 5 is also input, and a signal is generated from the logical product circuit (AND circuit) 9 through logical product. When stored in the memory circuit 19, the disconnection warning light 15 lights up.

At the same time, an OR circuit 10 outputs a signal, which turns off the power to an automatic machine such as a packaging machine.

As described above, the present invention can easily detect an abnormality when an electromagnetic solenoid is blocked from operating by an obstacle or is disconnected, and can also be used to detect an abnormality caused by an overcurrent or an abnormality caused by a disconnection or an obstruction. Appropriate measures such as stopping the entire machine can be taken to prevent the machine from malfunctioning or parts from burning out.

[Brief explanation of the drawing]

Each of the figures shows an embodiment of the present invention. Fig. 1 is a block diagram, Fig. 2 is a current waveform in a normal case, and Fig. 3 is a current when the electromagnetic solenoid 1 is prevented from operating by an obstacle. Shows waveform. 1... Electromagnetic solenoid, 2, 3... Switch, 4...-- Starting current detection device, 5...
・Timer circuit, 6... logical product circuit (AND circuit), 7... starting current memory circuit, 8...
Negation circuit, 9... logical product circuit (AND circuit),
10...Logical sum circuit (OR circuit).

Claims (1)

[Scope of Claims] 1. A circuit for detecting the starting current of an electromagnetic solenoid, a circuit for ANDing a starting signal from the detection circuit and a driving signal for the electromagnetic solenoid delayed by a certain period of time using a timer circuit, etc.; An electromagnetic solenoid abnormality detection circuit comprising a circuit that ANDs a signal obtained by storing and negating a starting signal from a circuit for detecting the starting current of the electromagnetic solenoid and a signal obtained by delaying the driving signal of the electromagnetic solenoid by a certain period of time using a timer circuit or the like. Device. 2. An electromagnetic solenoid abnormality detection device according to claim 1, in which a photocoupler is connected in parallel with a resistor to a diode bridge as a circuit for detecting a starting current.