Function Code 16: Store Multiple Setpoints - GE 489 Instruction Manual

6.2 MODBUS FUNCTIONS
Modbus Implementation:
489 Implementation:
This function code allows multiple Setpoints to be stored into the 489 memory. Modbus "registers" are 16-bit (two byte) val-
ues transmitted high order byte first. Thus all 489 setpoints are sent as two bytes. The maximum number of Setpoints that
can be stored in one transmission is dependent on the slave device. Modbus allows up to a maximum of 60 holding regis-
ters to be stored. The 489 response to this function code is to echo the slave address, function code, starting address, the
number of Setpoints stored, and the CRC.
MESSAGE FORMAT AND EXAMPLE
Request slave 11 to store the value 01F4 to Setpoint address 1180 and the value 0001 to setpoint address 1181. After the
transmission in this example is complete, 489 slave 11 will have the following setpoints information stored:
ADDRESS DATA
1180 01F4
1181 0001
MASTER TRANSMISSION:
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
BYTE COUNT
DATA 1
DATA 2
CRC
SLAVE RESPONSE:
6
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS
NUMBER OF SETPOINTS
CRC
6-6
Preset Multiple Registers
Store Multiple Setpoints
BYTES EXAMPLE (hex):
1 0B
1 10
2 11 80
2 00 02
1 04
2 01 F4
2 00 01
2 9B 89
BYTES EXAMPLE (hex):
1 0B
1 10
2 11 80
2 00 02
2 45 B6
489 Generator Management Relay

6.2.7 FUNCTION CODE 16: STORE MULTIPLE SETPOINTS

message for slave 11
store setpoints
data starting at 1180
2 setpoints (4 bytes total)
2 registers = 4 bytes
data for address 1180
data for address 1181
CRC calculated by the master
response message from slave 11
store setpoints
data starting at 1180
2 setpoints (4 bytes total)
CRC calculated by the slave
6 COMMUNICATIONS
GE Multilin