Instruction manual

5. RKC COMMUNICATION PROTOCOL
IMR01H02-E3
19
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 data is not sent from the host computer even if the data link is initialized
• 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.
(6) ACK (Acknowledgment)
An acknowledgment ACK is sent by the host computer when data received is correct. When the
controller receives ACK from the host computer, the controller will send any remaining data of the
next identifier without additional action from the host computer.
For the identifier, see #
##
# Communication identifier list (P. 35).
When host computer determines to terminate the data link, EOT is sent from the host computer.
(7) NAK (Negative acknowledge)
If the host computer does not receive correct data from the controller, it sends a negative
acknowledgment NAK to the controller. The controller will re-send the same data when NAK is
received. This cycle will go on continuously until either recovery is achieved or the data link is
corrected at the host computer.
BCCETX0001M005STX
03H30H30H35H30H30H30H31H4DH
Hexadecimal numbers