What does it take to build a minimal modbus compatible system?
What I would to do is create a few virtual systems that each have their own IP address and emulate a modbus system like a PLC with some data that is fluctuating.
Then get the data to the central system.
My main focus is to test firewall on what impact they have on SCADA networks without having an actual SCADA plan available.
(I am more Linux and CLI oriented guy then a Windows and clicking type of guy.)