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We are using modbus protocol in Ge multilin relays for all the drives above 75 Kw and for HT drives 1500 Kw we use alstom relay 241 series. We control, start and stop through modbus communication. Our PLC is AC450 of ABB system. After commissioning the system ABB now says the responce time is for start and stop will be 5 seconds. The five seconds also varies up to 12 sec in alstom relays to stop the coresponding drives. We already taken care by intoduced hardware tripping for the most critical drives. We like to know whether the response time will be 5 to 10 sec as claimed by ABB? We hardly exchage three to four register per slave. And we connected to maxmimum of 12 slaves in critical bus cables. Can any one give us sugest us how to increase the responce time in modbus communication
2nd question is: the communication always trips in the bus which have repeaters. this is hapening ones in two days? we solve by disconnecting the connector in the repeater and give start from PLC and reconnect the connector in the repeater.
2nd question is: the communication always trips in the bus which have repeaters. this is hapening ones in two days? we solve by disconnecting the connector in the repeater and give start from PLC and reconnect the connector in the repeater.