GE 1601-0149-A2

Modbus Functions 489

Communications Guide

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GE Multilin

Function Code 05:

Execute Operation

Modbus Implementation: Force Single Coil

489 Implementation: Execute Operation

This function code allows the master to request specific 489 command operations.

The command numbers listed in the Commands area of the memory map

correspond to operation code for function code 05. The operation commands can

also be initiated by writing to the Commands area of the memory map using

function code 16. Refer to Section Function Code 16: Store Multiple Setpoints on

page –7 for complete details.

Supported Operations:Reset 489 (operation code 1); Generator Start (operation

code 2);

Generator Stop (operation code 3); Waveform Trigger (operation code 4)

Message Format and Example:

Reset 489 (operation code 1).

Function Code 06: Store

Single Setpoint

Modbus Implementation: Preset Single Register

489 Implementation: Store Single Setpoint

This command allows the master to store a single setpoint into the 489 memory.

The slave response to this function code is to echo the entire master transmission.

Message Format and Example:

Request slave 11 to store the value 01F4 in Setpoint address 1180. After the

transmission in this example is complete, Setpoints address 1180 will contain the

value 01F4.

Master Transmission Bytes Example Description

Slave Address 1 0B message for slave 11

Function Code 1 05 execute operation

Operation Code 2 00 01 reset command (op code 1)

Code Value 2 FF 00 perform function

CRC (low, high) 2 DD 50 computed CRC error code

Slave Response Bytes Example Description

Slave Address 1 0B message from slave 11