08-19-2013 10:23 AM
Hello,
I am trying to use modbus tcp/ip to send data (start stop signals) over to a Schneider Electric Quantum Plc running Unity Pro Software. I am new to this area of communcation, and have both downloaded and tried to use modbus TCP/IP with the DSC module. however, I didnt get any communcation and I was thinking maybe using OPC Servers might work. Has anyone done something similar or have any suggestions? and if OPC will work, can you provide some steps or details on how to implement this communication.
Thanks,
Joaquin
08-19-2013 11:21 PM
One thing to check is whether you are using the correct version of the modbus protocol. There is an ascii version that transfers data as human-readable strings and an RTU version that sends the data as binary.
Mike...
08-20-2013 09:56 AM
Hi,
Thanks for your reply. I am not using serial communication. I actually need it to connect through TCP/IP. Both ASCII and RTU communication are for Modbus Serial communication.
Joaquin
08-20-2013 01:01 PM
Yes, but if its expecting one and gets the other it won't communicate.
Mike...
08-20-2013 01:01 PM
Yes, but if its expecting one and gets the other it won't communicate.
Mike...
08-20-2013 03:58 PM
If I understood correctly from this paper
http://www.ni.com/white-paper/7675/en/
Serial communication will be the one that will use RTU or ASCII
TCP/IP communication is different all on its own.
Regards,
Joaquin
08-20-2013 10:43 PM
the way modbus over TCP/IP works is that it uses the same protocol but with the TCP/IP connection carrying the data rather than rs232 or rs485.
Mike...
PS: ethernet is serial communications too...