So, are you saying that what you were observing and reporting as backlash may have been uncoordinated motion by the DSP controller?
Stuff like that is why I was recommending a static measurement of backlash rather than inferring backlash from print quality or some other indirect method. True backlash should be relatively easy to measure. If something can be measured directly, that is by far my preference. No point introducing complexity and uncertainty about what you're measuring or observing. That can lead to replacing belts with ball screws when the belts were actually OK.
This is a slim possibility, but I have no real way of proving it - unless I can get my hands on a pulse counter - I've attached a screendump of my system settings. I'm not entirely sure it's actually the case. I have also cut a 500mm L shape where the line is cut contiguously - effectively nulling any backlash as that would have been taken up in it's initial positioning (I purposely set the directions then nailed the datum) and there have been no reverse directional changes made - the lines were orthogonal and of equal length.
Doing a quick calculation, over 500mm, the step count difference between the two axes is 22328 steps. At the X step size, that equates to just over 1.9mm - which seems quite a lot over 500mm. I did some further testing last night, and my machine cuts dead square and size accurate to within 0.05mm 'ish - over the 150mm my vernier works. Over 150 to 500, it's difficult to gauge accurately - flat ended steel rules aren't really that accurate (dimensionally), but are fine for consistency - my sizes are consistently the same in X & Y. Different materials give differing results of course as expected. I do see an amount of backlash on wee circles (3mm or less) - it's visible, hardly measureable accurately - but I now cheat and set those circles to be cut at a much slower rate which improves matters.
I use an offset of 0.1mm which is fine for any work that I need an accurate fit on (mainly balsa/liteply/acrylic) - this is with a 63.5mm lens.
To be honest, it can all get a bit anal can't it
At the end of the day, I'm only cutting bits of wood and what I get from the system is perfectly OK. My real feeling is that this is all mechanical imperfection, but I'd like to just count the pulses to give me a nice psychological warm feeling anyway
I apologise if this is hijacking Gav's thread, I'm not intending to - I just don't want to see his ballscrews go to waste LOL
It may all be a factor.
I'm not sure I understand what a 'static backlash' measurement is 'though ? By inference, 'backlash' has to include movement?