CHAPTER 3: MODBUS FUNCTIONS
FUNCTION CODE 06H: STORE SINGLE SETPOINT
750/760 FEEDER MANAGEMENT RELAY – COMMUNICATIONS GUIDE
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Function Code 06H: Store Single Setpoint
This function code allows the master to modify the contents of a single setpoint register in
a 750/760. Setpoint registers are always 16 bit (two byte) values transmitted high-order
byte first (see the section
Modbus Memory Map
on page 4-1 for details). The following table
shows the format of the master and slave packets. It shows a master device storing the
value 200 at memory map address 1100h to slave device 11.
Function Code 10H: Store Multiple Setpoints
This function code allows the master to modify the contents of a one or more consecutive
setpoint registers in a 750/760. Setpoint registers are 16 bit (two byte) values transmitted
high-order byte first. The maximum number of setpoint registers that can be stored in a
single packet is 60. The table below shows the format of the master and slave packets. It
shows a master device storing the value 200 at memory map address 1100h, and the
value 1 at memory map address 1101h to slave device 11.
Master Transmission
Bytes
Example
Description
Slave Address
1
11
message for slave 11
Function Code
1
06
store single setpoint
Data Starting Address
2
11 00
data starting at 1100h
Data
2
00 C8
data for address 1100h
CRC (low, high)
2
8F F0
computed CRC error code
Slave Response
Bytes
Example
Description
Slave Address
1
11
message from slave 11
Function Code
1
06
store single setpoint value
Data Starting Address
2
11 00
data starting at 1100h
Data
2
00 C8
data for address 1100h
CRC (low, high)
2
8F F0
computed CRC error code
Master Transmission
Bytes
Example
Description
Slave Address
1
11
message for slave 11
Function Code
1
10
store multiple setpoint value
Data Starting Address
2
11 00
data starting at 1100h
Number of Setpoints
2
00 02
2 setpoints = 4 bytes total
Byte Count
1
04
4 bytes of data
Data #1
2
00 C8
data for address 1100h
Data #2
2
00 01
data for address 1101h
CRC (low, high)
2
27 01
computed CRC error code
Slave Response
Bytes
Example
Description
Slave Address
1
11
message from slave 11
Function Code
1
10
store multiple setpoint value