GE GFK-1541B - Manual (Page 116)

GFK-1541B 4-1
Programming Modbus/TCP Channel Commands
This chapter describes how to program communications over the Ethernet network using
Modbus/TCP
® Channel commands. Details of the Communications Request (COMMREQ)
function and the Modbus/TCP Channel commands are presented here. To program SRTP
Channel commands, see chapter 3. To use the Modbus/TCP Server capability within the Ethernet
Interfact, consult Appendix E about translating PLC reference memory addresses to Modbus
Register addresses.
ƒ The Communications Request
ƒ The COMMREQ Function Block and Command Block
ƒ Modbus/TCP Channel Commands
ƒ Status Data
ƒ Controlling Communications in the Ladder Program, which includes an example
Note
This chapter applies only to Series 90-30 Ethernet Interface IC693CMM321-FH
or later.
This chapter applies only to PLCs being used as client PLCs to initiate
Modbus/TCP communications. No programming is required for Modbus/TCP
server operations, however it is necessary to use the “Modbus Register to
IC693CMM321 Reference Table Translation” provided in Appendix E to
correctly address PLC reference memory using Modbus/TCP to a
IC693CMM321.
4
Chapter