| 摘要 |
The electric press is provided with a main CPU 1 and a sub CPU 3, the main CPU 1 being responsive to a signal from a servo driver 10 to give an detecting signal to a relay 2 when a ram 51 is located in a predetermined position, thereby to give a mute signal to an area sensor 30 and the sub CPU 3 being responsive to a signal from an encoder 9 to give a detecting signal to a relay 4 when the ram is located in a predetermined position, thereby to give a mute signal to the area sensor 30. The main CPU 1 and sub CPU 3 watch each other, that is, the main CPU 1 checks the output of a relay 4 and turns the relay 2 off when the mute signal is not produced from the relay 4. The conditions of sub CPU and main CPU are compared with each other. In case the two conditions are in accord with each other, it is decided that the relay 4 is out of order. The sub CPU 3 makes the same check operation in connection with the relay 2.
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