Problem with the repeatability of position reading (capacitive scale)

[ChazzC]

Left side, aluminum scales. I think the aluminum scales develop contact problems and that's the main issue. Despite adding additional capacitance between Vcc and Gnd, the readout was unstable until I made a hard connection between the scale and sensor GND.

I have two stainless-steel igaging DROs attached to my mini lathe and they also exhibited some problems....until I added the bypass capacitors. After that they settled right down, no need for that external ground connection. I don't use flood or mist lubrication so I expect the contact surfaces to stay pretty clean.

Odd, but then I looked back at my email exchanges with Yuriy in 2021 concerning grounding or isolating the scales from my mill and he advised waiting to see if there was an issue:

"This is a perfect application for "if it ain't broke, don't fix it". In my experience, more than 90% of iGaging setups just work. I've sold hundreds of the old boards and have heard from a few dozen people about any problems. Most often it's the flickering last digit, which you can't really fix anyway (although the new firmware does some shenanigans to reduce the flickering)."​

Maybe I'm just lucky; even Yuriy can't believe I don't have issues on my lathe install due to the way I "routed" the iGaging cables:

Yuriy's reaction earlier this year:

You know, some people jump through all sorts of hoops to get these scales to behave. This includes careful cable routing, grounding, shielding, etc. The gods of electronics must REALLY love you if your scales work fine with that box of spaghetti (or, the cables are so tangled that noise can't figure out how to get into them...)​

Charlie "Blessed by the Gods of Electronics"