GE 489 Communications Guide

489 GENERATOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE 9
CG.2.8 Function Code 16: Performing Commands
Some PLCs may not support execution of commands using function code 5 but do support
storing multiple setpoints using function code 16. To perform this operation using function
code 16 (10h), a certain sequence of commands must be written at the same time to the
489. The sequence consists of: Command Function register, Command operation register
and Command Data (if required). The Command Function register must be written with the
value of 5 indicating an execute operation is requested. The Command Operation register
must then be written with a valid command operation number from the list of commands
shown in the memory map. The Command Data registers must be written with valid data if
the command operation requires data. The selected command will execute immediately
upon receipt of a valid transmission.
Message Format and Example:
Perform a 489 RESET (operation code 1).
Master Transmission Bytes Example Description
Slave Address 1 0B message for slave 11
Function Code 1 10 store setpoints
Data Starting Address 2 11 80 data starting at 1180h
Number of Setpoints 2 00 02 2 setpoints = 4 bytes total
Byte Count 1 04 2 registers = 4 bytes
Data 1 2 01 F4 data for address 1180h
Data 2 2 00 01 data for address 1181h
CRC (low, high) 2 9B 89 computed CRC error code
Slave Response Bytes Example Description
Slave Address 1 0B message from slave 11
Function Code 1 10 store multiple setpoints
Data Starting Address 2 11 80 data starting at 1180h
Number of Setpoints 2 00 02 2 setpoints (4 bytes total)
CRC (low, high) 2 45 B6 computed CRC error code
Master Transmission Bytes Example Description
Slave Address 1 0B message for slave 11
Function Code 1 10 store setpoints
Data Starting Address 2 00 80 setpoint address 0080h
Number of Setpoints 2 00 02 2 setpoints = 4 bytes total
Byte Count 1 04 2 registers = 4 bytes
Command Function 2 00 05 data for address 0080h
Command Function 2 00 01 data for address 0081h
CRC (low, high) 2 0B D6 computed CRC error code
Slave Response Bytes Example Description
Slave Address 1 0B message from slave 11
Function Code 1 10 store multiple setpoints
Data Starting Address 2 00 80 setpoint address 0080h

GE 489 Specifications

General

Brand	GE
Model	489
Category	Relays
Language	English