Troubleshooting Glass Scale Issue

So I am settled on the problem being the spring in the read head. Here is what I got from trouble shooting using the mentioned info:

When two scales are moved simultaneously they both do not lose signal at the same time or in the same places. This along with using different power supplies ruled out voltage drops as being the common problem.

The micro controller and voltage shift circuit are good. Each scale would react the same way (stop sending signals) pretty consistently in the same spots and directions. With each scale doing it in different locations then the others regardless of which axis on the controller/dro I plugged it into. So to me that narrows it down to the scales.

I tested continuity 10 ways to Sunday. Pulled the heads all apart and surprisingly could not get a short to appear in any wires. I did notice that this brand uses actual wired inside the read head verus other brands that use the ribbon conduit. I believe the head relies some what on these wires to apply some pressure to the front of the head and keep it on the glass. When I reassembled the heads and tweeked the spring the scale worked almost flawlessly. The only time I could get it fail was pulling the read head to its maximum distance from the scale and then sliding it. Which isn't an issue for my setup as all the scales have a close tolerance. I could not however find a happy place on the spring that would allow the scale to work no matter what orientation I had it in.

So in conclusion, adjusting the springs has made the scale work so long as you the scale and head are moved parallel to each other. I think an additional light spring on the opposite side as the original spring would benefit the design. Or a Teflon spacer that rode in the scale conduit keeping the reader up against the glass may be another option. For now they are going back on until the issue surfaces again. (Think the springs relax overtime). Just hate having the question of reliability in the back of my head.

Thank you for the help and suggestions.
 
I am having the same issue with a couple of my ditron scales. Your spring tweak, was it just adding some more tension to the head that corrected your issues?
 
Yes that seemed to fix it for me. Is your scale doing this while installed or while you move it free hand?
 
Both freehand as well as installed. It has really thrown me for a loop as it has worked perfectly fine for almost a year on my Lathe. Then suddenly my cross slide scale started to glitch, while trying to troubleshoot it, my carriage scale started to do the same thing. I have pulled them apart and cleaned them with Alcohol, tried swapping things around, checked power supply etc. I am using them with a Shumatech DRO and am fortunate to have a friend locally that I could borrow his and it is doing the same thing with that DRO, so I know its not the DRO.
 
From what I saw the wires leading to the read head also acted as a spring to keep the head aligned. Trying manipulating those as well to force the head to the glass. My last ditch effort was going to be to epoxy some Teflon to the head to force it to stay in place.

You probably did this but also make sure the glass is clean and free of debris. If it happens in the same location it could be debris.

To me the issue revolved around the head leaving the glass being what caused the miss counts. I also tried to see if the wires had a short but could not find one.
 
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