X axis not working correctly

[Yuriy]

Scale connected to one half of 339. Clock and data connected to P2.1 and P2.4. Powered up, connected. Scale and display zeroed. Scale moved, display Y axis and scale value match.
Powered down, P2.1 linked to P2.0 P2.4 linked to P2.5, powered up ,connected.
Y axis display now continually jumping about. If the scale is moved X axis value changes and a number shows without changing most of the time but then for a fraction will show a completely different number.. 
Powered down.
Just for fun P2.1 linked to P2.5 and P2.4 linked to P2.0. Powered up connected.
X axis jumps about erratically however Y axis now stable and correct and following the scale.

Is the controller trying to supply the clock? I believe you need to do that on some types of scales.

Let me know if you need more tests
ATB
Richard

Richard,
Mixed firmware provides the clock via a separate pin. 
Do you have pull up or pull up resistor on the input pins? Are those the same value?
Also, do you have another chip to try. It's unlikely that the silicone is defective but not completely implausible.

Regards
Yuriy

[edeeec]

There are pull ups of 3.9K (to the 3.3v rail) on the LM339 outputs to the Launchpad. A new LM339 was fitted with exactly the same results as previously.
Richard

[Yuriy]

There are pull ups of 3.9K (to the 3.3v rail) on the LM339 outputs to the Launchpad. A new LM339 was fitted with exactly the same results as previously.
Richard

Richard,
3.9K is a good value for a pull-up, so you're OK there. I meant a different MSP430; I'd be shocked if a comparator was partially bad. On the other hand I've seen partially damaged MSP430s.
Thank you
Yuriy

[edeeec]

OK I fully assessed what I had built and binned it!
Too many errors! I rebuilt the Shifter circuit and now have a system that is PERFECT 80% of the time. The Y axis sometimes goes Doo Lally and shows very high numbers but then reverts back to the current scale display. I cannot say exactly why this happens or exactly how it recovers back to being stable again which it does (sometimes).Since seeing the problem I changed the 10K resistor on the Y axis to 39K to hopefully set the virtual ground at 1v. This seems to have reduced the visits to La La Land but not stopped them entirely. I have 100nf caps on the Virtual Ground and all of the wiring is "solid" now, no long wires except those out to the displays.
The system is now usable but still irritating.
Comments would be appreciated.
ATB
Richard

[edeeec]

I felt I should end the thread.
Binned the project completely. Could not cure the jumping display, gave up and have moved on to other things.

[Briney Eye]

I felt I should end the thread.
Binned the project completely. Could not cure the jumping display, gave up and have moved on to other things.

I had to go into my Shars/Shahe/Accuremote scale read heads and add 100nf VDD to GND to make them behave.

They can get away with minimal decoupling when running on batteries, but not when connected to a common return.

[heavyg603]

I felt I should end the thread.
Binned the project completely. Could not cure the jumping display, gave up and have moved on to other things.

I had to go into my Shars/Shahe/Accuremote scale read heads and add 100nf VDD to GND to make them behave.

They can get away with minimal decoupling when running on batteries, but not when connected to a common return.

Any chance I could get you to post a few pics of that fix ?  Might be having the same issue......

[Briney Eye]

I posted pics on another thread. Try https://forum.yuriystoys.com/showthread.php?tid=129.

Good luck!

[keesk]

Yuriy,
we have the same problem here at my friends DRO, he has four scales that reacts exacty the same.
Is there some progress on this problem?

KeesK

[Philcobt]

Hi Yuriy

I have a similar problem to the above using scales from Machine DRO (UK) using the Do-it-yourself DRO Mixed Scale Controller Kit. I have changed the MSP430, put each scale in the various X, Y & Z inputs, all with no improvement. The Y axis seems most jittery, jumping from 0.00mm to 10403mm (0 to 409inch) and back again, but all axis jump in this way. They all revert to the same base number after jumping up to 10,000+mm.
I have checked all soldered joints and all seem OK.
Is there any thing else I can try or is it a Bin6 conversion problem that I read somewhere?
Is there an update on the code due soon please?
Regards,
Barry (UK)