Store Multiple Settings (Function Code 10H); Exception Responses - GE UR Series Manual

MODBUS FUNCTION CODES
Table 2-8: Master and slave device packet transmission example
Master transmission
Packet format
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS - high
2 DATA STARTING ADDRESS - low
DATA - high
DATA - low
CRC - low
CRC - high

2.2.5 Store multiple settings (function code 10h)

This function code allows the master to modify the contents of a one or more consecutive setting registers in a relay.
Setting registers are 16-bit (two byte) values transmitted high order byte first. The maximum number of setting registers
that can be stored in a single packet is 60. The following table shows the format of the master and slave packets in Modbus
RTU. Modbus TCP/IP ADUs have a MBAP instead of slave address, and CRC is in another stack layer. The example shows a
master device storing the value 200 at memory map address 4051h, and the value 1 at memory map address 4052h to
slave device 11h (17 decimal).
Table 2-9: Master and slave device packet transmission example
Master transmission
Packet format
SLAVE ADDRESS
FUNCTION CODE
DATA STARTING ADDRESS - hi
DATA STARTING ADDRESS - lo
NUMBER OF SETTINGS - hi
NUMBER OF SETTINGS - lo
BYTE COUNT
DATA #1 - high order byte
DATA #1 - low order byte
DATA #2 - high order byte
DATA #2 - low order byte
CRC - low order byte
CRC - high order byte

2.2.6 Exception responses

Programming or operation errors usually happen because of illegal data in a packet. These errors result in an exception
response from the slave. The slave detecting one of these errors sends a response packet to the master with the high order
bit of the function code set to 1.
The following table shows the format of the master and slave packets in Modbus RTU. Modbus TCP/IP ADUs have a MBAP
instead of slave address, and CRC is in another stack layer. The example shows a master device sending the unsupported
function code 39h to slave device 11h.
2-6
Slave response
Example (Hex) Packet format
11 SLAVE ADDRESS
06 FUNCTION CODE
40 DATA STARTING ADDRESS - high
51 DATA STARTING ADDRESS - low
00 DATA - high
C8 DATA - low
CE CRC - low
DD CRC - high
Slave response
Example (Hex) Packet format
11 SLAVE ADDRESS
10 FUNCTION CODE
40 DATA STARTING ADDRESS - hi
51 DATA STARTING ADDRESS - lo
00 NUMBER OF SETTINGS - hi
02 NUMBER OF SETTINGS - lo
04 CRC - lo
00 CRC - hi
C8
00
01
12
62
CHAPTER 2: MODBUS COMMUNICATION
Example (Hex)
11
06
40
51
00
C8
CE
DD
Example (Hex)
11
10
40
51
00
02
07
64
UR SERIES – COMMUNICATIONS GUIDE