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GE <I> manual for MODBUS part explains only single-to-single connection, and GE Industrial Service told us their system doesn't support multi-drop link.
We're working on Cogen plant with GE Mark V and HMI (GE brand name) monitoring system. We planned to hook up one HMI and 3 or 4 other Modbus slave devices in a multi-drop Modbus link. But as mentioned in Summary, GE is saying that it's not supported, and I could not find any hard evidence that we can use RS-232/RS-485 converter and just put HMI in the multi-drop link.
As my understanding if you have any device can talk to Modbus protocol you can hook it up in the multidrop RS-485 communication link.
But I could not find any solid evidence in Modicon Modbus Protocol Reference Guide, PI-MBUS-300, Rev. J that my field proven experience is right.
If there is anybody who has experience with GE <I> station or HMI station with Modbus multidrop interface to DCS system, please let me have some advice and idea.
Regards,
Won Chul Shin, P. Eng.
Senior Controls Engineer
Fluor Canada Ltd.
(403) 298-4988
We're working on Cogen plant with GE Mark V and HMI (GE brand name) monitoring system. We planned to hook up one HMI and 3 or 4 other Modbus slave devices in a multi-drop Modbus link. But as mentioned in Summary, GE is saying that it's not supported, and I could not find any hard evidence that we can use RS-232/RS-485 converter and just put HMI in the multi-drop link.
As my understanding if you have any device can talk to Modbus protocol you can hook it up in the multidrop RS-485 communication link.
But I could not find any solid evidence in Modicon Modbus Protocol Reference Guide, PI-MBUS-300, Rev. J that my field proven experience is right.
If there is anybody who has experience with GE <I> station or HMI station with Modbus multidrop interface to DCS system, please let me have some advice and idea.
Regards,
Won Chul Shin, P. Eng.
Senior Controls Engineer
Fluor Canada Ltd.
(403) 298-4988