Instruction manual

11
(3) Message example of RTU mode
1
Reading (Address 1, PV)
• Request message from the master
The number of data indicates the data item to be read, and it is fixed as (0001H).
(Fig. 6.3-2)
• Response message from the slave in normal status [When PV=25
(0019H)]
The number of response bytes indicates number of bytes of the data which has been read, and
it is fixed as (02H).
(Fig. 6.3-3)
2
Reading (Address 1, Pattern 1, Step 1 step SV)
• Request message from the master
The number of data indicates the data item to be read, and it is fixed as (0001H).
(Fig. 6.3-4)
• Response message from the slave in normal status [SV=600
(0258H)]
The number of response bytes indicates number of bytes of the data which has been read, and it
is fixed as (02H).
(Fig. 6.3-5)
• Response message from the slave in abnormal status (When data item is mistaken)
The function code MSB is set to 1 for the response message in abnormal status (83H).
If an abnormal code (02H: Non-existent data address) is returned, the error can be determined
by reading this code.
(Fig. 6.3-6)
3
Setting (Address 1, Pattern 1, Step 1 step SV)
When setting the step SV to 600
(0258H)
• Request message from the master
(Fig. 6.3-7)
• Response message from the slave in normal status
(Fig. 6.3-8)
3.5 idle
characters
Slave
address
Function
code
Data item
Error check
CRC
3.5 idle
characters
(01H) (03H) (0080H)
Number of
data
(0001H) (85E2H)
11 2 2 2
Number of
characters
3.5 idle
characters
Slave
address
Function
code
Number of
response bytes
Error check
CRC
3.5 idle
characters
(01H) (03H) (02H)
Data
(0019H) (798EH)
11 1 2 2
Number of
characters
3.5 idle
characters
Slave
address
Function
code
Data
item
3.5 idle
characters
(01H) (06H) (1110H)
11 2
2
Number of
characters
Data
2
Error check
CRC
8DA9H
(0258H)
3.5 idle
characters
Slave
address
Function
code
Data item
Error check
CRC
3.5 idle
characters
(01H) (03H) (1110H)
Number of
data
(0001H) (80F3H)
11 2 2 2
Number of
characters
3.5 idle
characters
Slave
address
Function
code
Number of
response bytes
Error check
CRC
3.5 idle
characters
(01H) (03H) (02H)
Data
(0258H) (B8DEH)
11 1 2 2
Number of
characters
3.5 idle
characters
Slave
address
Function
code
Abnormal
code
Error check
CRC
3.5 idle
characters
(01H) (83H) (02H) (C0F1H)
11 1 2
Number of
characters
3.5 idle
characters
Slave
address
Function
code
Data
item
3.5 idle
characters
(01H) (06H) (1110H)
11 2
2
Number of
characters
Data
2
Error check
CRC
8DA9H
(0258H)