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Title:
MOTOR MULTIRELAY AND PLANT MONITOR AND CONTROL SYSTEM
Document Type and Number:
Japanese Patent JP3619068
Kind Code:
B2
Abstract:

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.


Inventors:
Suzuki Osamu
Hideo Onishi
Hiroyuki Suzuki
Hiroki Tatsuya
Application Number:
JP22022699A
Publication Date:
February 09, 2005
Filing Date:
August 03, 1999
Export Citation:
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Assignee:
株式会社日立製作所
International Classes:
G05B23/02; (IPC1-7): G05B23/02
Domestic Patent References:
JP11032405A
JP5128960A
JP63019727A
JP8147012A
Attorney, Agent or Firm:
Katsuo Ogawa
Kyosuke Tanaka