C Ommands - GE 489 Communications Manual

CG.2.8 Function Code 16: Performing Commands
489 GENERATOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE
Master Transmission
Slave Address
Function Code
Data Starting Address
Number of Setpoints
Byte Count
Data 1
Data 2
CRC (low, high)
Slave Response
Slave Address
Function Code
Data Starting Address
Number of Setpoints
CRC (low, high)
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
Slave Address
Function Code
Data Starting Address
Number of Setpoints
Byte Count
Command Function
Command Function
CRC (low, high)
Slave Response
Slave Address
Function Code
Data Starting Address
Bytes Example
1 0B message for slave 11
1 10 store setpoints
2 11 80 data starting at 1180h
2 00 02 2 setpoints = 4 bytes total
1 04 2 registers = 4 bytes
2 01 F4 data for address 1180h
2 00 01 data for address 1181h
2 9B 89 computed CRC error code
Bytes Example
1 0B message from slave 11
1 10 store multiple setpoints
2 11 80 data starting at 1180h
2 00 02 2 setpoints (4 bytes total)
2 45 B6 computed CRC error code
Bytes Example
1 0B message for slave 11
1 10 store setpoints
2 00 80 setpoint address 0080h
2 00 02 2 setpoints = 4 bytes total
1 04 2 registers = 4 bytes
2 00 05 data for address 0080h
2 00 01 data for address 0081h
2 0B D6 computed CRC error code
Bytes Example
1 0B message from slave 11
1 10 store multiple setpoints
2 00 80 setpoint address 0080h
Description
Description
Description
Description
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