RKC INSTRUMENT Z-TIO-G, Instruction Manual, Page: 57 / 246

6. RKC COMMUNICATION
IMS01T28-E4
6-5
5. ETX
Transmission control character indicating the end of the text.
6. BCC
BCC (Block Check Character) detects error by using horizontal parity (even number).
Calculation method of BCC:
Exclusive OR
all data and characters from STX through ETB or
ETX, not including STX.
Example:
STX M 1 0 1 1 5 0 . 0 ETX BCC
4DH 31H 30H 31H 20H 20H 31H 35H 30H 2EH 30H 03H
BCC = 4DH

31H

30H

31H

20H

20H

31H

35H

30H

2EH

30H

03H = 54H
(

:
Exclusive OR
)
Value of BCC becomes 54H
(4) EOT send (Ending data transmission from the SRZ)
In the following cases, the SRZ sends EOT to terminate the data link:

When the specified identifier is invalid

When there is an error in the data format

When all the data has been sent
(5) No response from the SRZ
The SRZ 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 SRZ
receives ACK from the host computer, the SRZ will send any remaining data of the next identifier without
additional action from the host computer.

When ACK was sent in succession for Z-TIO module, identifier data item down to “Communication
switch for logic” in the communication identifier list are sent.
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 SRZ, it sends a negative acknowledgment NAK
to the SRZ. The SRZ 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.
Hexadecimal numbers