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5.6.2 RTU Mode
Numerals written below the command represent the number of characters.
(1) Read (Slave address 1, PV)
• A request message from the master
Slave
3.5 idle
address
characters
(01H)
• Response message from the slave in normal status [When PV is 600
Slave
3.5 idle
address
characters
(01H)
(2) Write (Slave address 1, SV1)
• A request message from the master [When SV1 is set to 600 (0258H)]
Slave
3.5 idle
address
characters
(01H)
• Response message from the slave in normal status
Slave
3.5 idle
address
characters
(01H)
• Response message from the slave in exception (error) status (When a value out of the setting range is set)
The function code MSB is set to 1 for the response message in exception (error) status, and 86H is
returned.
Exception code 03H (Value out of the setting range) is returned (error).
Slave
3.5 idle
address
characters
(01H)
(3) Read [Slave address 1, SV1)
• A request message from the master
Slave
3.5 idle
address
characters
(01H)
• Response message from the slave in normal status [When SV1 is 600
Slave
3.5 idle
address
characters
(01H)
• Response message from the slave in exception (error) status (When a data item is misread)
The function code MSB is set to 1 for the response message in exception (error) status, and 83H
is returned. Exception code 02H (Non-existent data address) is returned (error).
Slave
3.5 idle
address
characters
(01H)
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Function
code
(03H)
1
1
Function
Number of
code
response bytes
(03H)
1
1
Function
code
(06H)
1
1
Function
code
(06H)
1
1
Function
Exception code
code
(86H)
1
1
Function
code
(03H)
1
1
Function
Number of
code
response bytes
(03H)
1
1
Function
Exception code
code
(83H)
1
1
Data item
Amount of data
(0100H)
(0001H)
2
2
Data
(02H)
(0258H)
1
2
Data item
Data
(0001H)
(0258H)
2
2
Data item
Data
(0001H)
(0258H)
2
2
Error check
CRC-16
(03H)
(0261H)
1
2
Data item
Data
(0001H)
(0001H)
2
2
Data
(02H)
(0258H)
1
2
Error check
CRC-16
(02H)
(C0F1H)
1
2
Error check
3.5 idle
CRC-16
characters
(85F6H)
2
(0258H)]
Error check
3.5 idle
CRC-16
characters
(B8DEH)
2
Error check
3.5 idle
CRC-16
characters
(D890H)
2
Error check
3.5 idle
CRC-16
characters
(D890H)
2
3.5 idle
characters
Error check
3.5 idle
CRC-16
characters
(D5CAH)
2
(0258H)]
Error check
3.5 idle
CRC-16
characters
(B8DEH)
2
3.5 idle
characters
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