I just wanted to post about my experience with one type of device that simulates a COM Port over Ethernet to extend the distance for monitoring TRi-PLC (specifically the T100MD888+). I used a DigiOne SP device and a crossover lan cable to connect to the T100 and monitored it on-line using the TRi-Logi Server on COM4.
I am going to use this to connect to an existing computer that is located ~300 feet away which is now monitoring an Allen-Bradley SLC500 through iFix Intellution.
Note that the DigiOne SP only simulates a standard RS-232 ports and does not implement Modbus or any other protocols. I mention this because I considered using the more expensive DigiOne IA which does implement Modbus protocol. Obviously, this requirement is not necessary for the TRi-Logi devices and server.
