Chapter 9 Modbus/Tcp Client; The Communications Request - GE RX3i User Manual

Chapter 9 Modbus/TCP Client

This chapter explains how to program communications over the Ethernet network using Modbus/TCP Channel
commands. This chapter applies only to PLCs being used as client PLCs to initiate Modbus/TCP
communications.
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The Communications Request

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The COMMREQ Function Block and Command Block
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Modbus/TCP Channel Commands
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Status Data
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Controlling Communications in the Ladder Program
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Differences between Series 90 and PACSystems Modbus/TCP Channels
The Communications Request
9.1
"Communications Request" is a term used to describe all the user elements required for correctly initiating
Channel commands in the client. No programming of Communications Requests is required for devices acting
as servers
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