1 interfaces, 1 com a and com b pin configuration, Interfaces – Beijer Electronics RBC EN User Manual
Page 5: Com a and com b pin configuration, Com a and com b pin configuration, Rs232 mode, Rs485 mode
Hardware
1.1 Interfaces
Related information
1.1.1
COM A and COM B Pin Configuration
The COM A and COM B ports are 9 pin D-SUB female ports.
5 4 3 2 1
9 8 7 6
RS232 Mode
Pin
Designation
Function
Pin
Designation
Function
1
+5 V
+5 V
6
–
Not connected
2
TxD
Transmit data
7
–
Not connected
3
RxD
Receive data
8
–
Do not connect
4
–
Not connected
9
GND
Ground
5
GND
Ground
RS485 Mode
Pin
Designation
Function
Pin
Designation
Function
1
+5 V
+5 V
6
–
Not connected
2
485+
Differential signal
7
–
Not connected
3
–
Do not connect
8
485–
Differential signal
4
–
Do not connect
9
GND
Ground
5
GND
Ground
Note:
The different pins of COM A and COM B are hard–wired to each other. This means that
using both interfaces at the same time is only allowed in RS485 mode. In RS232 mode
only one interface can be used.
Note:
In RS485 mode the switching from receiving to transmitting and back must be
performed very fast (typical 20 µs). Not all COM ports or adapters support such a speed.
Make sure that the hardware used is fast enough.
Related information
Serial Mode DIP Switch Settings
Beijer Electronics, MAEN986C
5