Mitsubishi Electric MELSEC iQ-R04ENCPU - Read File Record (FC: 14 H) (SC: 06 H)

3 MODBUS STANDARD FUNCTION DETAILS
3.14 Read File Record (FC: 14H) (SC: 06H)
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3.14 Read File Record (FC: 14H) (SC: 06H)
Operation description
Reads the values of multiple extended file register areas.
Request message format (from master to slave)
• Specify the number of sub requests, m, so that the size of the protocol data unit of the request message
does not exceed 253 bytes. The request message will be discarded if the following condition is not met.
[Conditional formula] 253  2 + (m  7)
• Specify the total number of read points of each sub request, N (n1 + ... + nm), so that the size of the protocol
data unit of the response message does not exceed 253 bytes. The slave will return an abnormal response
if the following condition is not met.
[Conditional formula] 253  2 + (m  2) + (N  2)
• File number specification: The upper limit of the file numbers that can be received by an Ethernet-equipped module is the file register size of the mounted
CPU module.
(H) (L)
14H
(H) (L) (H) ( L)
(H) (L) (H) (L) (H) (L)
(06H)
(06H)
Number of
bytes m×7
Data
File number specification
Function code
Read start device number
Sub-request 1
Reference
number
Number of read points n1
Data
File number specification
Read start device number
Sub-request m
Reference
number
Number of read points nm
Number of bytes m×7
Number of bytes m×7
(0000H to FFFFH) (0000H to 270FH) (0001H to 007CH)
(0000H to FFFFH) (0000H to 270FH) (0001H to 007CH)