6-14
469 Motor Management Relay
GE Power Management
6.2 SUPPORTED MODBUS FUNCTIONS
6 COMMUNICATIONS
6
6.2.9 FUNCTION CODE 16: PERFORMING COMMANDS
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:
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 0080
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 0080
COMMAND OPERATION
2
00 01
data for address 0081
CRC
2
0B D6
CRC calculated by the master
SLAVE RESPONSE:
BYTES
EXAMPLE / DESCRIPTION
SLAVE ADDRESS
1
0B
response message from slave 11
FUNCTION CODE
1
10
store setpoints
DATA STARTING ADDRESS
2
00 80
setpoint address 0080
NUMBER OF SETPOINTS
2
00 02
2 setpoints (4 bytes total)
CRC
2
40 8A
CRC calculated by the slave
