| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of an emergency stop circuit for a long-term use by simplifying a duplex emergency stop circuit employed in an automatic machine. SOLUTION: When an emergency stop signal is input, relays KA1, KA2 become (OFF, OFF), and emergency stop lines 1, 2 are both opened, and an output contact is opened. When the emergency stop signal is released, a condenser is charged. When a reset is input, electric current is supplied to coils of the relays KA1, KA2, and monitor contacts KA1-2, KA2-2 are opened. However, excitation for the coils of the relays KA1, KA2 is maintained by the discharge current from the condenser, and self-holding contacts KA1-1, KA2-1 are closed and the output contact is closed. For example, if the normally open contact KA1-1 is welded, relays KA1, KA2 become (ON, OFF) when the emergency stop signal is released, and the trouble becomes clear. Instead of the relays KA1, KA2, for example, a 24 V drive type electromagnetic contactor may be used. COPYRIGHT: (C)2004,JPO&NCIPI
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