Hello all,

I'm trying to use the serial port provided on both Eurotherm 6100A recorder and Scheiner Quantum PLC to use RTU modbus to "put" info available in the recorder in the modbus memory of the PLC. The main constraint (if it is really a constraint,... so far and as long as I now, it is...) is that the recorder plays slave role.

I have checked that PLC correctly performs its master query, but (don't know why), the recorder is not answering properly. After talking to Eurotherm technical support, they said "nothing must be bear in mind to make the recorder work as a modbus slave", but if I change the recorder by a program simulating a modbus slave, there is no problem.

Is there anything particular in the slave configuration of the Eurotherm 6100A that must be known in this communication? I guess it is a typical topology, so maybe someone of you guys can help me in any way.

Thanks a lot in advance.