TCP_IP_ADDR and Momentum PLC

I am trying to read Modbus/TCP data from a switchgear protective relay into a Momentum PLC using Concept 2.6. I tried to use the I/O scanner, but the relay will only allow two reads, and I need to get registers from throughout its map. A colleague suggested using the READ_REG function. I tried to use the TCP_IP_ADDR function, but I haven't been able to get a successful read.

Can the TCP_IP_ADDR function be used in a Momentum PLC? If so, what goes into the Slot_ID input? I am assuming the slave ID goes into the Map_Idx input.

Thanks in advance,
Steve