B&R BRCOMP1-0 Anwenderhandbuch Seite 208

B&R COMPACT PLC
RS232 Interface - Point to Point:
The RT bit is normally set for RS232 communication. If the user wants to set a busy signal, the RT bit
can be set to "0".
NOTE: If the RT bit is "0", this sender is also inactive!
The following diagram shows signals in an RS232 communication.
Data register
written to
+12 V
TXD
-12 V
+12 V
RXD
-12 V
+12 V
RTS
Line
-12 V
- 208 -
Data register
written to
Data register This byte will be
read read completely
Busy signal set
(RT = "0")
RTS line only goes to -12 V after
the character is sent completely
NOTE: The originating sender is also inactive.
Data register
written to
Send/recieve is possible again
(RT = "1")
Data register
read