Connection of Pin 6 (Ground) of VN7572
Must pin 6 of the D-SUB62 connector of VN7572 be directly connected to ground?
The shield connection pin 6 is an HF ground. It is connected to the VN7572 signal ground via 1MΩ and 1 nF.
The GND of each individual channel on DSUB9 pin 3 are isolated from it.
The female shield is directly connected to the signal ground.
If the interconnection of the devices should result in undesirable equalizing currents via the shield, pin 6 offers the possibility of only HF grounding the cable shield here.
Normally, however, it remains unused and an existing shielding is connected directly to the connector housing.