| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a motor multirelay which can detect a trip due to equipment abnormality without using a straight forward cable, and a plant monitor and control system which is applied with this motor multirelay. SOLUTION: An MMR 1 is provided with a Stop 17 switch and a CPU 16 broadcasts to a serial transmission line 4 a transmit signal including operation bits with an inverse contact signal which is turned ON when the Stop switch is opened and clock bits obtained by integrating the number of clocks of a transmitter 15 by monitor cycles. The CPU 16 of the MMR 1 and an SQC 5 checks received data of MMRs received from a transmission line in order, checks the operation bit when the clock still has a last value and there is MMR with communication abnormality, and decides that the MMR is in a trip state when the operation bit is OFF. When the operation bit is ON, it is decided that a breaker is artificially opened.</p> |
