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4. Example of TOHO Communication
4.1 Sample Communication for Reading
Example:
Request Message: Request this product, which address is set as "27," to read the measured value
(PV).
(Upper computer)
For the above request,
Response Message: Returns the data (00777) of the measured value (PV).
(This product)
Read Request Message (to be sent by the upper computer)
S
T
X
2 7 R
B
C
C
P V 1
E
T
X
① ② ③
|
④
|
⑥ ⑦
S
T
X
2 7
A
C
K
B
C
C
P V 1
E
T
X
① ② ⑧
|
④
|
⑥ ⑦
0 0 7 7 7
|
|
⑤
|
|
Code
Symbol
・
Data
ASCII Code Note 2)
① Start Code
STX
02H
② Address
27
32H 37H
③ Contents of Request
R (Read)
52H
④ Identifier Note 1
PV1
50H 56H 31H
⑤ Numerical Data
00777
30H 30H 37H 37H 37H
⑥ End Code
ETX
03H
⑦ BCC Data Request
Response
61H
02H
⑧ Acknowledgment Code
ACK
06H
Note 1: See "9. List of Identifiers (Codes)."
Note 2: See "10. List of ASCII Codes" for the details about ASCII codes.