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5. RKC COMMUNICATION PROTOCOL
IMR01J08-E1
15
1.
STX
STX is the transmission control character which indicates the start of the text transmission
(identifier and data).
2.
Identifier (2 digits)
The identifier indicates the type of data (measured value, status and set value) sent to the host
computer.
For details, see
5.3 Communication Identifier List (P. 22)
.
3.
Data (6 digits [Expect model code and ROM version number.] )
Data is the information being sent from the controller. It is expressed in decimal ASCII code
including a minus sign (-) and a decimal point. No zero suppression is made.
4.
ETX
ETX is a transmission control character used to indicate the end of text transmission.
5.
BCC
BCC (Block Check Character) detects error using horizontal parity and is calculated by
horizontal parity (even number).
Calculation method of BCC:
Exclusive OR
all data and characters from STX through ETX, not
including STX.
Example:
BCC = 4DH
⊕
31H
⊕
30H
⊕
30H
⊕
30H
⊕
35H
⊕
30H
⊕
30H
⊕
03H = 7AH
Value of BCC becomes 7AH.
(4) EOT sent from the controller (Ending data transmission from the controller)
In the following cases, the controller sends EOT to terminate the data link:
•
When the specified identifier is invalid
•
When there is an error in the data type
•
When all the data has been sent
(5) No response from the controller
The controller will not respond if the polling address is not received correctly. It may be necessary for
the host computer to take corrective action such as a time-out.
BCC
ETX
0
0
0
1
M
0
0
5
STX
30H 03H
30H
35H
30H
30H
30H
31H
4DH
Hexadecimal numbers