Centroid Community CNC Support Forum

For my encoders I have only solderd the shielding from the original cable to the DB9 metal part. Works fine.

Uwe

tblough wrote: ↑Sun Jul 03, 2022 11:16 am Connecting one end or both of the shield borders on religion for some. Crusades and jihads have been waged on this topic and a gathering of 10 experts will get three different majority decisions.

Personally, I connect the shield at the end where the signal originates for control signals (I.e. currents that are affected by noise) and both ends of power leads (I.e. noise generators). Your mileage may vary.

However, as previously mentioned an ounce of prevention is worth a pound of cure. Find the cause of the interference and fix that.

Having worked for a building automation company for almost 20 years we tried the ground issue both ways! If both ends of the wire hook to a until with the same ground potential, then grounding both ends is OK. However, we found that anything that had separate power circuits never had 0 ground potential between the two points.

So the proven way, and I'm talking systems with over 30,000 control points, was to ground the drain wire at the "source" end only thus eliminating any differential in ground potential. Plus we made sure that all wires from any one panel were grounded at the same end!

There are some exceptions to this rule but none that apply to a CNC control panel mounted close by a machine!

Side bar: I've wired three sound recording studios and one digital television production suite! All mic and line cables are only grounded at one end!

Dave C.

I connect my shields on one end to the ground plane I mount the components on. This is also is the earth ground and a common ground point for any DC power supplies. Is there any reason not to? So far no issues doing it this way on 4 different machines.

Upnorth wrote: ↑Sun Jul 03, 2022 5:38 pm I connect my shields on one end to the ground plane I mount the components on. This is also is the earth ground and a common ground point for any DC power supplies. Is there any reason not to? So far no issues doing it this way on 4 different machines.

Single point ground is the best way! (All ground wires to one grounding point or buss bar) Just make sure the backplane has a post with no paint, or use a bare spot, because the paint itself presents itself as a capacitor and changes the ground potential.