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from the Automation List department...
Modbus connection problem
HMI topic
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Posted by Tuan on 16 January, 2008 - 12:49 am

Hi,

I'm having a big headache with a communication problem with Modbus network.
I have 2 (RS232) PLCs connected to an (RS485) Exter K70 HMI in a multidrop network with the K70 as Master. 2 PLCs use RS232/485 Electro Industries converters. Well, everything works fine when the RS232 cable is unplugged from Station 2 and then plugged back. But when Station 1 is disconnected and replugged, the communication does not get restored unless the HMI is restarted. Any help would be much appreciated.


PLC 1 ---[Unicom 2500] == [Unicom 2500] --- PLC 2
||
||
[exter k70]

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