CANopen (x510)
The CAN bus line is connected via a 9-pin D-sub connector with the following pin assignment:
Pin  | Connection  | 
|---|---|
1  | not used  | 
2  | CAN low (CAN-)  | 
3  | CAN Ground (internally connected to pin 6)  | 
4  | not used  | 
5  | Shield  | 
6  | CAN Ground (internally connected to pin 3)  | 
7  | CAN high (CAN+)  | 
8  | not used  | 
9  | not used  | 
For the CANopen optional interface (x510), documentation with further information is available:
https://infosys.beckhoff.com/content/1033/m510_b510_canopen_optioninterface/index.html?id=1404127979601372947
Document name  | 
|---|
CXxxxx-M510/B510 | CANopen Optional Interface  |