grounding stepper driver & power supply

Hi

I’m running a motion control rig with an Arduino and 6 Big Easy Drivers and steppers. It is powered with a Mean Well 24V 14.6A power-supply. its all working fine. Now I wanted to do some configurations and change 4 of the BED’s with Vexta-drivers (and motors).

Now I’m not sure how to connect all the grounds (PE, Frame, PC). Do they need to be connected all to one point on the enclosure (I’m using an aluminium pc-case). Or do they need to be separated? I read different things about it and just wanted to be sure to prevent any EMI or even shock hazard.

Attached are the schematics of the driver and power supply installation.

Thanks!

Screen Shot 2014-03-24 at 15.29.58.png

All share common ground. but !!! Do not connect MCUs usb if the PC is connected to a grounded wallsocket. (use a laptop running off battery) Such a connection can result in a destructive current through the USB-port