24
3 MODBUS STANDARD FUNCTION DETAILS
3.8 Diagnostics (FC: 08H)
Return diagnostic register (sub-function code: 02H)
Operation description
Reads out the detailed LED status of C24 to the master.
Request message format (from master to slave)
Response message format (from slave to master)
■ When completed successfully
In the C24, the detailed LED status of 'CH1/2 side LED lighting status and communication error status' of the buffer memory
(Un\G513/Un\G514) is stored as the diagnostic register.
■ When completed with an error
(H) (L)
08H (0002H) (0000H)
(H) (L)
DataFunction code Sub-function code
(H) (L)
08H (0002H)
(H) (L)
b0b1b2b3b4b5b6b7b8b9b10b11b12b13b14b15
0 0 0 1/0 1/0 1/0 1/0 1/0 0 0 0 1/0 1/0 1/0 1/0 1/0
CH1 C/N
CH1 P/S
CH1 PRO.
CH1 SIO
CH1 ERR.
CH2 C/N
CH2 P/S
CH2 PRO.
CH2 SIO
CH2 ERR.
DataFunction code Sub-function code
Diagnostic register value
CH1 side Detailed
LED status
(0: OFF, 1: ON)
CH2 side Detailed
LED status
(0: OFF, 1: ON)
Unused (Fixed to 0)
Unused (Fixed to 0)
88H
Data
Exception code
Function code