I have a RUT955 with a modbus RTU RS485 device connected directly. The 955 is a OpenVPN client. I have successfully setup the RTU device to be available via a modbusTCP connection via OpenVPN by allowing connection from the OpenVPN server IP on port 502. This all works fine.
I want to also monitor the RUT955 itself using modbusTCP, if I turn on the modbus TCP service and allow remtoe connection at a port like 50023, this will work but the connection to the RS485 device will stop working.
Why does this happen? Can both work at the same time ? Any help is greatly appreciated :)
EDIT: The Modbus monitoring is being done by the same SCADA software on the OpenVPN server, at same IP.