Read Input Registers (Fc: 04H) - Mitsubishi Electric MELSEC iQ-R Series Reference Manual

3.4

Read Input Registers (FC: 04H)

Operation description
Reads one or multiple input register values.
Request message format (from master to slave)
Function code
Start input register number
specification
04H (0000H to FFFFH)
(H)
Response message format (from slave to master)
■ When completed successfully
Function code
Number of read
bytes n×2
04H
• For example, when n = 4, the number of read bytes is 4  2 = 8.
■ When completed with an error
Function code Data
Exception code
84H
Data
Number of read points
(0001H to 007DH)
(L) (H)
Data
Device data 1
(H) (L)
Number of read bytes n×2
(L)
Device data n
(H) (L)
3 MODBUS STANDARD FUNCTION DETAILS
3.4 Read Input Registers (FC: 04H)
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