4. COMMUNICATION PROTOCOL
IMCD06-E2
21
Identifier [Number of digits: 2] (See P. 28.)
This is for identifying data (measured value, status and set value) sent to the host computer.
Data [Number of digits: 6]
Data indicated by the identifier belonging to the controller. It is expressed in decimal ASCII code
including a minus sing (-) and a decimal point. No zero suppression is made.
[ETX]
A transmission control character used to indicate text end.
[BCC]
BCC (Block Check Character) for error detection using horizontal parity. BCC is calculated by
horizontal parity (even number).
<Algorithm>
Take off EX-OR (exclusive "or") of all character from next [STX] through [ETX].
Not including [STX].
Example:
In the case of the data are :
BCC = 4DH ⊕ 31H ⊕ 30H ⊕ 30H ⊕ 30H ⊕ 35H ⊕ 30H ⊕ 30H ⊕ 03H = 7AH
Value of BCC becomes 7AH.
(4) Controller data send end (EOT send)
If the following cases, the controller sends [EOT] to terminate the data link.
When there is no specified identifier.
When there is an error in the data type.
After all the data has been sent.
When a identifier not added to the controller is specified.
(5) Controller no response
The controller is set to no response when the polling sequence is not received correctly. If necessary,
take time out recovery etc. for the host computer.
BCC ETX 0 0 0 1 M 0 0 5 STX
30H 30H 35H 30H 30H 30H 31H 4DH
In the parenthesis are indicated with
hexadecimal number.
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