Function Code 16: Performing Commands - GE MOTOR MANAGEMENT RELAY 469 Instruction Manual

6.2 SUPPORTED MODBUS FUNCTIONS
Some PLCs may not support execution of commands using function code 5 but do support storing multiple set-
points 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 469. 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 reset on 469 (operation code 1)
MASTER TRANSMISSION:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
BYTE COUNT
COMMAND FUNCTION
COMMAND OPERATION
CRC
SLAVE RESPONSE:
6
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
CRC
6-14

6.2.9 FUNCTION CODE 16: PERFORMING COMMANDS

BYTES EXAMPLE / DESCRIPTION
1 0B message for slave 11
1 10 store setpoints
2 00 80 setpoint address 0080
2 00 02 2 setpoints (4 bytes total)
1 04 2 registers = 4 bytes
2 00 05 data for address 0080
2 00 01 data for address 0081
2 0B D6 CRC calculated by the master
BYTES EXAMPLE / DESCRIPTION
1 0B response message from slave 11
1 10 store setpoints
2 00 80 setpoint address 0080
2 00 02 2 setpoints (4 bytes total)
2 40 8A CRC calculated by the slave
469 Motor Management Relay
6 COMMUNICATIONS
GE Power Management