YouTube video showing how shielded cable works

[Richards]

Here's a YouTube video by Tim Wilborne that shows how shielded cable reduces electrical interference. His area of interest is using PLCs for process control, but OUR use of VFDs, stepper drives, and servo drives overlaps. He also has videos about building industrial control boxes.

Here's the link for the video:

[DrLocke]

My machine is close to a highway with just a large window between electronics and passing traffic. I recently installed cat-8 ethernet cables between the computer, acorn, and ether1616. This reduced the number of communication errors from maybe a few per day to less than 1-2 per week. You should consider upgrading if you are in a unshielded noisy location and have multiple comm errors. Google cat-8 to see the differences with cat-5/6.

[Richards]

In my shop, the shielded ethernet cable supplied by Centroidcnc works well, but it's good to know that CAT-8 shielded cable might be even better.

When I designed process control computers, I was constantly fighting electrical noise so that there were no false triggers. At that time, I built everything with TTL logic. A LOW signal was between 0.0 and 0.7 VDC. A HIGH signal was between 2.2 and 5.0VDC. When prototyping, I used the 'scope constantly to watch each signal to verify that there was little or no noise being generated by my design. Most of the noise was eliminated by using Solid State Relays instead of mechanical relays, but then I had to plaster warning labels everywhere. Most of my customers didn't realize that an SSR "leaks" voltage, so the LOAD side of an SSR can give a good shock even when it is (supposedly) off. Now, with VFDs, stepper drivers and servo drivers, the electrical noise comes from different sources, but it still can trigger false signals if not controlled. Shielded cables, properly used, are a great way to reduce electrical noise.