Mitsubishi Electric MELSEC iQ-RJ71C24-R4 - Read Holding Registers (FC: 03 H)

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3 MODBUS STANDARD FUNCTION DETAILS
3.3 Read Holding Registers (FC: 03H)
3.3 Read Holding Registers (FC: 03H)
Operation description
Reads one or multiple holding register values.
Request message format (from master to slave)
Response message format (from slave to master)
■ When completed successfully
■ When completed with an error
• For example, when n = 4, the number of read bytes is 4  2 = 8.
(H) (L) (H) (L)
03H
Start holding register number
specification
Data
Number of read points
Function code
(0000H to FFFFH) (0001H to 007DH)
03H
(H) (L) (H) (L)
DataFunction code
Number of read
bytes n×2
Device data 1 Device data n
Number of read bytes n×2
83H
Data
Exception code
Function code