I've got a system that has several power meters connected to a MODGATE Ethernet Gateway over an ICOMM network. Then the gateway is connected to a NOE module on a Quantum rack. We are having some communication problems. I am looking at the PLC end while other are looking at the networking side. I would like to try to use a MSTR (MBP_MSTER?) block to grab the data I need, however I don't see how I can assign a unit id to the MSTR block. It seems that it just wants the IP address.

Alternatively I've looked at the READ_REQ block in conjuction with the TCP_IP_ADDR block. This looks promising, but I wonder if what they are callling "Map_Idx" is what I am calling unit ID. (For example on address 10.11.12.13 there are four power meters with unit IDs 1, 2, 3, and 4.)

I suppose you are programming a Quantum with Unity Pro.....
I don't know the MODGATE Gateway neither the ICOMM network, but I'm imaging you need to talk with devices having a serial port connected to the gateway connected to the ethernet network of the NOE. The MODGATE converts the protocol from MODBUS TCP to ICOMM protocol.

If you need to ciclically read or write (or both) tables of registers you could easily use the I/O Scanning service (Modbus Code 03-16-23)

Otherwise for an ethernet communication you have to use MBP_MSTR function block (better than others)

Because you are using a gateway the ID number will be :

for I/O Scanning the Unit ID column
for MBP_MSTR the CONTROL[5] = the most significant byte is the slot number of the NOE; the least significant byte is the address of the device


You could use also the READ_REG (or WRITE_REG or CREAD_REG, etc.) for reading once a table of registers and same as before the device address is

WordArr5[1] = the most significant byte is the slot number of the NOE; the least significant byte is the address of the device (or MAP index by using the TCP_IP_ADDR function block )




the address word

CONTROL[5]
or
WordArr5[1]

in binary code will be

00000111 00000001 (I suppose the NOE in slot 7) PM address 1
00000111 00000010 (I suppose the NOE in slot 7) PM address 2
00000111 00000011 (I suppose the NOE in slot 7) PM address 3
00000111 00000100 (I suppose the NOE in slot 7) PM address 4

I hope you could understand me... sorry for my english too