BECKHOFF CX1020 - Manual (Page 42)

Product overview
40 Embedded PC
CX1020-N031/41 connections
The CX1020-N031 system interface features two RS422 / RS 485 interfaces, COM1 and COM2 (9 pin Sub-D plug
connector). If there is need for more than two serial interfaces two further RS422 / RS485 interfaces, COM3 and
COM4 (9 pin Sub-D plug connector) can be added to the system via the system interface CX1020-N41. The
maximum baud rate on all channels is 115 kBit. The pin assignment for all interfaces is equal and described below.
The interface parameter can be set in the operating system or in the PLC program.
RS232 COM interface (connector):
Pin assignment COM interface:
PIN Signal Type Description
2 TxD+ Data-Out + Transmit 422
3 RxD+ Data-In + Receive 422
5 GND Ground Ground
6 VCC VCC +5V
7 TxD- Data-Out - Transmit 422
8 RxD- Data-In - Receive 422
For RS 485 Pin 2 and 3 ( Data +) as well as Pin7 and 8 (Data -) have to be connected..
Setting the interface parameter
If the system interface CX1020-N031/N041 resides at the end of the CX1020-system block, it is easy to access the
dip switches. The dip switches for the configuration of the RS485/422 interfaces can be found at the left side of the
module. If you remove the grey cover you can see the switch: