Panasonic KT4H - Modbus RTU Mode Message Examples and Error Handling; Modbus RTU Read SV Message Example (Address 1); Modbus RTU Set SV Message Example (Address 1)

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2
Reading (Address 1, SV)
• A request message from the master
The number of data means the data item to be read, and it is fixed as 1 (30H 30H 30H 31H).
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(30H 33H)
Data item
[0001H]
(30H 30H 30H 31H)
Number of data
[0001H]
(30H 30H 30H 31H)
Error check
LRC
(46H 41H)
Delimiter
CR+LF
(0DH 0AH)
• Response message from the slave in normal status (When SV=600 [0258H])
The number of response byte means the number of bytes of the data which has been read, and it is fixed
as 2 (30H 32H).
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(30H 33H)
Number of
response byte
[02H]
(30H 32H)
Data
[0258H]
(30H 32H 35H 38H)
Error check
LRC
(41H 30H)
Delimiter
CR+LF
(0DH 0AH)
• Response message from the slave in exception (error) status (When a data item has been mistaken)
The function code MSB is set to 1 for the response message in exception (error) status [83H (38H 33H)].
The exception code 02H (30H 32H: Non-existent data address) is returned.
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(38H 33H)
Exception code
[02H]
(30H 32H)
Error check
LRC
(37H 41H)
Delimiter
CR+LF
(0DH 0AH)
3
Setting (Address 1, SV) (When setting SV to 600 [0258H])
• A request message from the master
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(30H 36H)
Data item
[0001H]
(30H 30H 30H 31H)
Number of data
[0258H]
(30H 32H 35H 38H)
Error check
LRC
(39H 45H)
Delimiter
CR+LF
(0DH 0AH)
• Response message from the slave in normal status
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(30H 36H)
Data item
[0001H]
(30H 30H 30H 31H)
Data
[0258H]
(30H 32H 35H 38H)
Error check
LRC
(39H 45H)
Delimiter
CR+LF
(0DH 0AH)
• Response message from the slave in exception (error) status (When a value out of the setting range has
been set)
The function code MSB is set to 1 for the response message in exception (error) status [86H (38H 36H)].
The exception code 03H (30H 33H: Value out of the setting range) is returned.
Header
(3AH)
Slave
address
(30H 31H)
Function
code
(38H 36H)
Exception code
[03H]
(30H 33H)
Error check
LRC
(37H 36H)
Delimiter
CR+LF
(0DH 0AH)