(N) Operation via communication and its settings
44
Diagnostics (diagnosis of functions) (H08 or 08)
• A communication check can be made since the query message is sent and the query message is returned as it is as the
return message (subfunction code H00 function).
Subfunction code H00 (Return query data)
• Query message
• Normal response (Response message)
• Query message setting
• Content of normal response
With a normal response, the contents in the response are the same as those in (a) to (g) of the query message.
a. Transaction
identifier
b. Protocol
identifier
c. Length field
d. Unit
identifier
e. Function
f. Subfunction
g. Data
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
(8 bits)
H08
(8 bits)
H00
(8 bits)
H00
(8 bits)
H
(8 bits)
L
(8 bits)
a. Transaction
identifier
b. Protocol
identifier
c. Length field
d. Unit
identifier
e. Function
f. Subfunction
g. Data
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
(8 bits)
H08
(8 bits)
H00
(8 bits)
H00
(8 bits)
H
(8 bits)
L
(8 bits)
Message
Description
a
Transaction identifier
The master adds the data for the purpose of transaction control.
The same data is returned in the response from the slave.
b
Protocol identifier
Fixed to 0. (When the slave receives data other than 0, it does not send the response
message.)
0 is returned in the response from the slave.
c
Length field
The data length from the unit identifier to the data is stored in byte.
d
Unit identifier
Fixed to 255
e
Function
Set H08.
f
Subfunction
Set H0000.
g
Data
Any data 2 bytes long can be set. The setting range is H0000 to HFFFF.
