Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 130)

Binary Command Language
Appendix A
A-2
Channel Timeout (Scanner waiting for command)
A channel timeout occurs when the scanner is waiting for a command and
does not receive one within the specified time.
You can select the channel timeout through the LIST function. The front
panel timeout value defaults to 10 seconds. Selecting a value of zero
disables the channel timeout.
When a channel timeout occurs, the scanner stops communicating through
channel 0. The master must then re-initialize the communication.
Character Timeout (Master or scanner waiting for next character
in block)
A character timeout occurs when the time between characters (bytes) in a
command block, response block, CCR, or CCR response is greater than the
character timeout value.
The master can set the scanner’s character timeout value by sending the
desired value within the CCR. If the master sends a zero value, the scanner
defaults to the character timeout value appropriate for the current
communication rate configuration as shown in Table A.A.
Table A.A
Communication Rate Configuration
Communication Rate (bps) Character Timeout Default Value
110 1 second
150 600 ms
300 300 ms
600 150 ms
1200 to 19.2 80 ms
If the master or a scanner records a character timeout, it must be treated as
if a NAK were received. They stop transmitting for one character timeout
value and then reissue the command or response.
The scanner sends a NAK when it detects this timeout.