Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 138)

Binary Command Language
Appendix A
A-10
Table A.D
Approximate Character Times
Communication
Rate in bits/s
Approximate character transmit time
Rate in bits/s
10 bit character 8 bit character
110 91.0 ms 72.7 ms
150 66.7 ms 53.3 ms
300 33.3 ms 26.7 ms
600 16.7 ms 13.3 ms
1200 8.3 ms 6.7 ms
1800 5.6 ms 4.4 ms
2400 4.2 ms 3.3 ms
4800 2.1 ms 1.7 ms
9600 1.0 ms 0.83 ms
19200 0.52 ms 0.41 ms
The break character tells the scanner to terminate any previous
communication. Therefore, send a break character whenever you initiate
or terminate communication. Both the scanner and the master device
respond to a break at any time by stopping transmission (even in the
middle of a block).
Although not configurable on the scanner, some PLC-3 family modules
which use BCL, can also be configured for BREAK DISABLED. This
option is selected when the master is not capable of detecting a break sent
from the PLC-3. When the channel is configured with BREAK
DISABLED, the master must send break for a minimum of one second.
If the master device does not support a break character, you can initiate
communications by sending a valid command to the scanner.
Important: If you use this method, remember that the PLC-3 scanner may
not be in its initial communication state when you begin communicating
with it. This can cause the PLC-3 to respond with invalid results until a
timeout or other error causes it to terminate communication, return to its
initial state, and start over.