DRO Where it really is.
From to Actual physical position
1 +056 to -.042 .150
2 -042 to -.044 .100
3 -044 to -.046 .050
Each photo represents one press of +(4times) and then the - (4times) key
Ah! I see now. Weâre using different terminology. I read DRO as a LITERAL standalone/external digital readout attached to the motor. Lightburn and traditional stepper motors have no feedback loop. If you command movement x, Lightburn takes the step/mm value and calculates the number of pulses required to move x, then sends it and assumes the motor does so without error. Any discrepancy in the reported position would have to be mathematical, not physical.
I suspect you already know this.
Any chance this could be rounding error or incorrect setup in the steps/mm setting?
What if you run in metric, and avoid the unit conversion?
Please Please
If my lightburn screen dro is at 0.00 and I move it with a step size of .050 said dro should read .050 it does just that
If my lightburn screen dro is at the last position which is .050 and I move another .050 said dro should read .100 NOT .052
If my lightburn screen dro is at the last position which is .100 and I move another .050 said dro should read .150 NOT .054
If my lightburn screen dro is at the last position which is .150 and I move another .050 said dro should read .200 NOT .056
Agreed. My machine does exactly that.
Your machine goes from .050 to .052 to .054 to .056
You do realize that that is absolutely WRONG
No. It does what you said it should. Command +.050 x4 times and it reads .200.
Well you have the photos to see what mine is doing. And the exact setup using 2 different gcode sender read correctly at .050,. 100, .150, .200
I read another post here recently which made reference to rounding errors when converting. Iâm pretty sure Lightburn works natively in SI units, and two others on this thread have mentioned conversion as a possible problem. I realize that this sort of thing is frustrating, but please try doing as they have suggested, ie working in metric units, and then telling us the results - telling us all weâve missed the boat isnât going to help you 
I very regularly step my Z axis up and down in .5 and 1mm (.020" & .040" respectively, roughly) increments and lose track of where I am, so I check the âDROâ (get position) to confirm so I donât crash it.
Mine doesnt care if it is in inches or mm, the dro readout is still wrong.
I suspect something is wrong in your setup/config. Suggest double checking the step/mm calcs.
My setup config is listed above and works fine with other senders. Please look at it and tell me where it is wrong. Thank you.
Trying to get too complicated. My stepper motor is moving exactly .050 (translates to one revolution of my leadscrew) every time I press the key. THE DRO is what is not reading correctly. And for a 1/4 - 20tpi leadscrew that is exactly the correct distance.
A normal 1.8 degree stepper motor needs 200 full steps to make 1 revolution. You have 157.xxx
I donât know whatâs going on âunder the hoodâ in Lightburn, but I can say with confidence that both my DRO and physical measurements at full travel in three axes agree.
Well please tell me why this NEMA17 will turn my motor shaft exactly 360 degrees with this setting.
This also holds true for a NEMA23 that I have tested with and also another NEMA17.
I set my Lightburn up as you likely have have yours.
Took 5 captures. The first one is upon powering up the laser. The last one confirms Absolute positioning.
I see Lightburn acting as expected. I did not miss the boat, I am just not on your boat. I am curious why we get different results with the same apparent setup.
**** I found it !!!
My controller was reporting in mm ($10=0). When I switched it to $10=1, I got the same results as you did. Gibbâs Slap me if I am wrong, but I believe Lightburn does all math metric, and I suspect metric from the controller.
How are you measuring that 360 degrees? Youâre 100% certain itâs not 359.9 degrees or 360.1?
If I were doing this for myself, Iâd put a leadscrew and a dial indicator on the motor and be sure.
As I said, I donât know what wrong on your end. I thought it might be helpful to know the results youâre seeing arenât typical or representative of normal use cases. Being combative or defensive isnât productive. I have nothing of further value to add, so Iâm out.
Good luck and keep us posted.
I suspect that other software is ignoring the controllerâs reported position.
Now I just hope I can get my Lightburn settings back the way they were. 
Thank you. I donât understand how I get the correct readings with other gc senders. So it brings me back to the software and not GRBL having a error. If that is the case Lightburn should change their software to not recognize $13 in GRBL config. HOWEVER when I run my CO2 laser with Lightburn and use $13=1 I have not problems.
The above paragraph should set some folks to scratching their head.
I am also going to try to find the article that I read that explained in detail about the 157.xxx Step setting. I have no problems using that setting on multiiple machines.
I do thank you folks and will try the $13=0. If it solves the problem great. However the answer as to WHY has not seen the light of day yet.
The GRBL configuration of $13=1 has the machine report in inches. You want the machine to report in mm irrespective of units used. Try $13=0.
