Energy Meter Manual

<Toc> <Ind> <5. Modbus/RTU and ASCII Communication Protocols>
5-13
IM 77C01E01-10E
08 Performs loop back test
● Function
This function code is used to check connection for communication.
• For the format of response in the event of failure, see subsection 5.1.4.
• The “00” shown below (marked with an asterisk *) are fixed.
• Any value can be selected for transmit data.
● Message (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Start of
Message
Mark (:)
None
1
Error
Check
2
2
Station
Number
(ST-NO)
1
2
None
End of Message Mark
(CR + LF)
2
Function Code
(08)
1
2
00
0000
2
44
2
Transmit Data
(Arbitrary)
Message (continued)
● Response (for normal operation)
Element
Number of bytes
in RTU mode
Number of bytes
in ASCII mode
Start of
Message
Mark (:)
None
1
Error
Check
2
2
Station
Number
(ST-NO)
1
2
None
End of Message Mark
(CR + LF)
2
Function Code
(08)
1
2
00
0000
2
44
2
Same as
Transmit Data
Response (continued)
● Diagnostic Codes
Meaning
Command message return
Diagnostic Code
0000
Data
Arbitrary
● Example (ASCII mode)
Send data 0000 (fixed) and transmit data 04D2 (arbitrary) to the station number 11 to check
the connection for communication.
[Message] [:]0B08000004D217[CR][LF]
When the connection is normal, the following response same as the command will be
returned.
[Response] [:]0B08000004D217[CR][LF]