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How to configure Write_Var block to send Modbus requests to an RTU device on a TCP Gateway the with BMXNOC0401 communication module?

Issue:
How do I configure a Write_Var block to send Modbus requests to an RTU device on a TCP Gateway the with BMXNOC0401 or BMENOC03X1 communication modules?

Product Line:
M580
M340

Environment:
EcoStruxure Control Expert
Unity Pro

Resolution:
See below an example of Write_Var block for writing Modbus slave data through ETG100 gateway.

In ADDM block '0.3.0{192.168.1.21}1.TCP.MBS' where
Rack = 0
NOC module slot address = 3
Channel = 0
Gateway IP address = 192.168.1.21
Modbus slave id = 1
Message type = TCP
Protocol = Modbus(MBS)

In Write_Var block
OBJ: String declaring the type of object to write (%MW or %M)
Num: Index of the first object to write
NB: Number of objects to write
EMIS: Data to write
For more details check attached unity help documents.