Grounding Stepper Motor Drivers

[Larsson55]

The attached pic indicates one of the four drivers I have in my CNC machine to drive my 4 stepper motors. I have conflicting/confusing answers on how to ground the shielded cables feeding each driver. All feeding cables are 22 AWG, 4 conductors wrapped in aluminum foil with a bare grounding wire. The maximum length of a cable is about 14 feet and the minimum length about 7 feet.
A = 4 conductors feeding the signal to the driver from the breakout board.
B = Nothing connected as per manufacturer.
C = 2 conductors (BLK/RED) feeding 48VDC power to the driver from the power supply unit.
D =  4 conductors feeding power to each stepper motor.

My question is what to do with the bare grounding wire. Do I take the bare grounding wire to my star point ground from all 3 cables or from only cable A, C, D or any other combination?

Thank you

[rstofer]

I would ground the shield on one end only.  This will be dependent on how the connectors are made but, since the metallic jacks must be earth grounded, it should be easy to ground one end of the shield to the connector body.  I would cover the other end of the shield with shrink tubing to keep it insulated.  I do not want to form ground loops between the computer and the tool itself.

[Larsson55]

Sorry but my question is not which end of a cable to ground but rather which cable(s) to ground, There are 3 cables so which one do I ground? maybe all?
Thanks

[wraper]

A and B look like optically isolated inputs. If you ground them to anywhere at all, then do so from the opposite side, not at controller. No need to use shielded cables for C - power. It's advisable to ground the shield of the motor cable - D. The best way likely would be connecting the shield on both ends, to the chassis GND point on driver side and to the motor enclosure on opposite end.

[Larsson55]

A and B look like optically isolated inputs. If you ground them to anywhere at all, then do so from the opposite side, not at controller. No need to use shielded cables for C - power. It's advisable to ground the shield of the motor cable - D. The best way likely would be connecting the shield on both ends, to the chassis GND point on driver side and to the motor enclosure on opposite end.

Thanks for your time, all is clear now