GE GFK-1541B manual Programming Modbus/TCP Channel Commands

Chapter

4

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.

ƒThe Communications Request

ƒThe COMMREQ Function Block and Command Block

ƒModbus/TCP Channel Commands

ƒStatus Data

ƒControlling 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.

GFK-1541B 4-1