I try to connect rapidscada directly to a PLC using Modbus TCP. The PLC has the libmodbus library implmented to establish the modbus connection.
The PLC can communicate with test software and also with the Modbus simulator (plcsimulator.org).
On the rapidscada side, I have been able to manage the connection from rapidscada to the Modbus Simulator as well. It works in principle.
If I add a new communication line with new object to the rapidscada configuration and set the communication to Modbus TCP Server (TcpPort = 502, behavior = slave, connmode = shared, devselmode = byipaddress) the connection can not be established.
I tried all possible combinations, but the tcpport 502 is not opening.
It seems that the TCP Server is not running correctly.
Do you have any idea/advice how to go forward to check the issue?