Panasonic KT4H - Modbus RTU Examples: Reading SV and Setting SV; Modbus RTU Read SV Example (Address 1); Modbus RTU Set SV 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 (0001H).
3.5 idle
characters
Slave
address
(01H)
Function
code
(03H)
Data item
(0001H)
Number of data
(0001H)
Error check
CRC-16
(D5CAH)
3.5 idle
characters
• Response message from the slave in normal status (When SV=600 [0258H])
The number of response byte means number of bytes of the data which has been read, and it is
fixed as 2 (02H).
3.5 idle
characters
Slave
address
(01H)
Function
code
(03H)
Number of
response byte
(02H)
Number of data
(0258H)
Error check
CRC-16
(B8DEH)
3.5 idle
characters
• 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).
The exception code 02H (Non-existent data address) is returned.
3.5 idle
characters
Slave
address
(01H)
Function
code
(83H)
Exception code
(02H)
Error check
CRC-16
(C0F1H)
3.5 idle
characters
3
Setting (Address 1, SV) (When setting SV to 600 [0258H])
• A request message from the master
3.5 idle
characters
Slave
address
(01H)
Function
code
(06H)
Data item
(0001H)
Number of data
(0258H)
Error check
CRC-16
(D890H)
3.5 idle
characters
• Response message from the slave in normal status
3.5 idle
characters
Slave
address
(01H)
Function
code
(06H)
Data item
(0001H)
Number of data
(0258H)
Error check
CRC-16
(D890H)
3.5 idle
characters
• 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).
The exception code 03H (Value out of the setting range) is returned.
3.5 idle
characters
Slave
address
(01H)
Function
code
(86H)
Exception code
(03H)
Error check
CRC-16
(0261H)
3.5 idle
characters