Omron CJ1W-SCU32 Operation Manual page 266

7 Using Modbus-RTU Slave Mode
Read Holding Registers
Function
Reads multiple words from the DM or EM Area of the memory used for CJ-series Unit.
Command
Function Code
Starting Address
Quantity of Regis-
ters
* The address depends on the area that is allocated.
Response
Function Code
Byte Count
Register Value
* N = Quantity of Registers
Reading 3 Words from DM 1000 to DM 1002
Request
Function Code
Starting Address (H)
Starting Address (L)
Quantity of Registers (H)
Quantity of Registers (L)
15 14 13
DM1000 A
DM1001 5
DM1002 9
7-16
Length
1 byte
2 bytes
2 bytes
Length
1 byte
1 byte
N × 2 bytes
Data
03 hex Function Code
03 hex Byte Count
E8 hex Register Value (H) DM1000
00 hex Register Value (L) DM1000
03 hex Register Value (H) DM1001
Register Value (L) DM1001
Register Value (H) DM1002
Register Value (L) DM1002
12 11 10 9 8
B
6
7
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
Data
03 hex
0000 to 7FFF hex (*)
0001 to 007D hex
Data
03 hex
N × 2 (*)
Response
Data
03 hex
06 hex
AB hex
12 hex
56 hex
78 hex
97 hex
13 hex
7 6 5 4
1
7
1
3 2 1 0
2
8
3