JPH0673760B2 - Switch input device for press - Google Patents

Description

The present invention relates to a switch input device of a press.

[Prior Art] A large number of operation switches, limit switches, and the like are used in presses for automation and perfection of safety.
The number of presses equipped with a transfer mechanism, and the presses exceeding 1,000 Spm, is increasing more and more.

The switch input device of each such switch generally has the structure shown in FIG.

That is, each switch SW (one switch is shown in FIG. 4) is arranged in series with the full-wave rectifying element 13 and the AC power supply 1, and the photoelectric conversion element 14 forming the photocoupler 12 is connected.
It is configured to be input to the control device 8 via.

Therefore, for example, when the switch SW for press operation is turned on, the output signal S (here, a high level signal) based on the rectified signal from the photocoupler 12 is input to the control device 8 as a switch signal as shown in FIG. To be done. In addition, 11 is a filter.

[Problems to be Solved by the Invention] However, according to the above-described conventional structure, when the photocoupler 12 is short-circuited due to noise, element quality, etc., the switch SW is not operated as shown in FIG. 5B. The lifting control device 8 may act in the same manner as when the switch signal is input.

Further, when the input port of the control device 8 is formed to include the inverter 9 etc. as shown by the two-dot chain line in FIG.
Even if the inverter 9 breaks down, there is a possibility that it may malfunction due to the presence of a switch input as in the case where the photocoupler 12 is short-circuited.

As described above, the phenomenon that the switch input is performed electronically and electrically even though the operation switch and the limit switch do not operate is a high load and complicated mechanism, and a person approaches the movable body due to the blank supply and the like. Such a press is not allowed in terms of ensuring safety and preventing equipment damage.

An object of the present invention is to provide a switch input device for a press, which can recognize that a switch input has been made promptly and accurately only when the switch is operated and operated reliably, and which can ensure safe and reliable operation by eliminating conventional malfunctions. To provide.

[Means for Solving the Problem] According to the present invention, each switch and the rectifying element are arranged in series with an AC power supply, and a zero cross point of the AC voltage is detected and an interrupt signal is output to the AC power supply. When the interrupt signal generating means is connected and the output signal from the rectifying element and the interrupt signal from the interrupt signal generating means are input and it is determined that the output signal from the rectifying element is an alternating signal which is inverted by the interrupt signal. Further, an alternating signal identifying means for identifying the operation / operation input of the switch is provided.

[Operation] According to the present invention, when the switch is operated or actuated, the output signal is output from the rectifying elements connected in series.

On the other hand, the interrupt signal generation means detects the zero cross point of the AC power supply and generates an interrupt signal.

Then, in the alternating signal identifying means to which the output signal and the interrupt signal are input, it is determined whether or not the output signal is an inverted signal every time the interrupt signal is input, and it is identified as the alternating signal. Sometimes it is accepted as an operation / operation signal for the switch.

Therefore, even if there is a failure in a component such as a rectifying element and the terminal level of the rectifying element or the like is permanently at a high level or a low level, it is no longer necessary to handle the switch operation / operation input. Only when all the components are sound and the switch is operated / actuated, the switch input can be identified.

[Embodiment] An embodiment of the present invention will be described below with reference to FIG.

This switch input device comprises a rectifying circuit 10 and an interrupt signal generating means 20 connected to the AC power supply 1, and an alternating signal identifying means 30 connected to both of them 10. In addition,
In FIG. 1, for the switch SW and the rectifier circuit 10, only one switch SW is shown. Further, the alternating signal identifying means 30 is formed by utilizing a CPU or the like (not shown) forming the conventional control device (8) and its function.

First, the rectifier circuit 10 includes a switch SW, a filter 11 including a resistor and a capacitor, and a photocoupler 12. The photocoupler 12 is a light emitting type rectifying element 13 for half-wave rectification and a photoelectric conversion element.
It is an integrated type with 14. Switch SW and rectifier 13
It can be seen that and are arranged in series with the AC power supply 1. Therefore, when the switch SW is turned on, the switch signal (output signal S) corresponding to the rectification signal of the rectification element 13 is output from the photocoupler 12.

On the other hand, the interrupt signal generating means 20 includes a pair of photocouplers 21A and 21A.
B and flip-flop circuit 22, a pair of one-shot circuits
It is composed of 23A, 23B and NAND gate 24. In this embodiment, as shown in FIG. 2, the interrupt signal Sp is output at the zero cross point of the AC voltage of the AC power supply 1.

Next, the alternating signal identifying means 30 receives the output signal S from the rectifying element 13 and the interrupt signal Sp from the interrupt signal generating means 20 as an input, and outputs the output signal S from the rectifying element 13 (switch signal from the photocoupler 12). ) Is a means for distinguishing from an operation input or an operation input of the switch SW when it is judged that the alternating signal is inverted by the interrupt signal.

Specifically, it is identified by a CPU (not shown) or the like. In this embodiment, the timer interrupt signal St is generated from the interrupt signal Sp as shown in FIG. 2 and indirectly determined. This is to further increase the certainty. In detail, the time of each rising when the 50Hz AC power supply is full-wave rectified is divided into 5 and 2m
The timer interrupt signal St is generated for each s.

Here, the output signal S from the photocoupler 12 is the output signal S from the photocoupler 21A of the interrupt signal generating means 20 as shown in FIG.
Since the output signal Sb is equal to a (the output signal Sb is 180 degrees out of phase), the alternating signal identification means 30 outputs "0,
0,0,0,0 ”,“ 1,1,1,1,1 ”, and“ 0,0,0,0,0 ”are alternately generated and the alternating signal is inverted by the interrupt signal. It is formed to identify and confirm the switch input.

Next, the operation will be described.

In FIG. 1, when the switch SW is turned on, the output signal S shown in FIG. 2 is emitted from the rectifying element 13, that is, the photocoupler 12, and is input to the alternating signal identifying means 30. On the other hand, the interrupt signal generation means 20 outputs an interrupt signal Sp every 10 ms when the power supply frequency is 50 Hz, and inputs the alternating signal identification means 30.

Here, in the alternating signal identification means 30, 2ms from the interrupt signal Sp
Each timer interrupt signal St is generated, and it is determined whether the output signal S is an alternating signal which is inverted by the interrupt signal. If the output signal S is "0,0,0,0,0"-"1,1,1,1,1"-"0,0,0,0,
If "0" is repeated, it is judged as a switch input by distinguishing it from an alternating signal which is inverted by an interrupt signal. This switch input is used, for example, for press operation by a control device (8) similar to the conventional one [in this embodiment, integrated with the alternating signal identifying means 30].

If the output signal S is "0,0,0,0,0"-"0,0,0,0,0" or "1,1,1,1,1"-"1,1,1,1 If the signal is not an alternating signal such as "1,1" or has a level arrangement that is not inverted by an interrupt signal (see FIG. 2), it is not recognized as a switch input because of some failure.

Therefore, according to this embodiment, the rectifying circuit 10 including the switch SW, the rectifying element 13 (photocoupler 12) and the like, which are arranged in series with the AC power source 1, and the interrupt signal generating means 20 are connected to each other, and the rectifying element is connected. When the output signal S from the 13 and the interrupt signal Sp from the interrupt signal generating means 20 are input, the switch SW is operated when the output signal S from the rectifying element 13 is judged to be an alternating signal which is inverted by the interrupt signal. .Alternative signal identifying means 30 for identifying the operation input
Since it is provided with a switch, it is handled as a switch input only when it is identified as an alternating signal which is inverted by an interrupt signal. Therefore, if any of the components has an abnormality / failure, the switch input is not issued, so that the malfunction is eliminated, and safe and reliable press operation can be guaranteed.

Further, the alternating signal identifying means 30 generates a timer interrupt signal St which is further subdivided based on the interrupt signal Sp from the interrupt signal generating means 20, whereby the output signal S from the rectifying element 13 is an alternating signal. Since it is determined whether or not there is any, the reliability of the switch input that has worked more reliably increases.

Further, the alternating signal identifying means 30 is a conventional controller (8).
Since it is integrally configured by effectively utilizing the CPU and its functions, it is possible to make high-speed judgments at low cost without increasing the installation space.

In the above embodiments, the rectifying element 13 arranged in series with the switch SW is of the half-wave rectification type, but can be implemented by the full-wave rectification type. In this case, the identification mode of the alternating signal identification means 30 is set to "0, as shown in FIG.
It may be configured as "0"-"1,1,1"-"0,0".

Further, the timer interrupt signal St is generated from the interrupt signal Sp and the determination is made indirectly, but it is also possible to make the determination directly by the interrupt signal Sp.

Further, the rectified signal of the rectifying element 13 without the photocoupler 12 may be subjected to waveform shaping processing, if necessary, to be used as the output signal S.

[Effect of the Invention] According to the present invention, each switch and the rectifying element are arranged in series with an AC power source, and an interrupt signal generating means for detecting a zero cross point of the AC voltage and outputting an interrupt signal is connected to the AC power source. However, when the output signal from the rectifying element and the interrupt signal from the interrupt signal generating means are input, and the output signal from the rectifying element is determined to be an alternating signal which is inverted by the interrupt signal, the switch operation / operation input Since there is an alternating signal identification means for identifying, the switch input is not handled as a switch input when any of the components has an abnormality or a failure, and the switch input and quick It is possible to provide a switch input device for a press that can be surely identified and can ensure a safe and reliable press operation.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation, and FIG. 3 is a timing for explaining the operation of a modified example in which the rectifying element is a full-wave rectification system. FIG. 4 is a circuit diagram showing a conventional switch input device, and FIG. 5 is a diagram for explaining an output signal in a normal state and an output signal in a short circuit of a photocoupler. 1 ... AC power supply, 10 ... Rectifier circuit, 12 ... Photocoupler, 13 ... Rectifier element, 20 ... Interrupt signal generating means, 30 ... Alternate signal identifying means. SW ... switch,

Claims (1)

[Claims] 1. Each switch and the rectifying element are arranged in series with an AC power source, and an interrupt signal generating means for detecting a zero cross point of the AC voltage and outputting an interrupt signal is connected to the AC power source. When the output signal from the rectifying element and the interrupt signal from the interrupt signal generating means are input, and the output signal from the rectifying element is determined to be an alternating signal which is inverted by the interrupt signal, the switch operation / operation input A switch input device for a press, characterized in that an alternating signal identifying means for identifying