Okay i fount the error, i was not patient enough. The auto tune function needed a lot of time. Now it has finished but there is stil a problem. Its like the motor is always correcting the position. I uploaded the video on my drop box if you would take a look. Is there a setting for this? When the auto tuning is finished , does it give any messages that it has finished ? I also attached the seetings.
The actual eror goes from 0 to -1 and 0 to 1 when the motor is correcting the position

details:https://www.dropbox.com/sh/5zyu75x5e756ku1/AADZO8KOkRyX_a6qm7OCSv-pa?dl=0

That looks like you have a lot of backlash. For that amount of rotation of the screw I would be expecting a much larger count in the plugin, it is only moving 1 or 2 counts., so it would seem the screw is rotating but the axis is not moving and thus the scale if not registering movement.

I presume you have the correct value in Motor Tuning  in Mach for STEPS PER UNIT?

If it is indeed backlash you will have to eliminate it as you will not get things tuned very well, that is the downside of linear scales rather than encoders, any backlash and it is extremely hard to get a decent tune.
Hood

Yes the steps per unit is 800 like we said before in the previous steps. If im understanding, you would say that i have a bad ball screw ?  Yes the ball screw is constantly moving and the axis is still.
Oh man what a week everything goes wrong :/

 Thanks Hood i would not know what to do without your help!
You are a HERO!


Best regards

That amount of rotation of the screw without movement would be much worse than I could imagine from a bad ballscrew.
I would think it much more likely that the fixing of the ball nut or the bearings on the screw are loose or damaged, check to see where the looseness is before contemplating replacing the screw. Bearings will be a lot cheaper than a screw and loose adjusting nuts will be free to fix

Hood

okay i have connected the Z axis and it has also movement (you can see it n the link of drop box). I was looking at the movements and i can not say if one is moving mor then the other.
If i fit the measurement gauge to the axis i donˇt get any movement. But when i give in to the axis calibration to move for 0.01 mm the axis moves for this amount.
Is it possible to tighten the ball nut ? I have no experience. Do you have any suggestions how can i  check the bearings?
I have checked all the screws that hold the nut in place and they are all ok.
There is a strange thing when i click apply there is no movement for a couple of seconds, than it starts again to move.
My motivation is at the bottom wright now,  because i have spend a lot of money on this machine and as far as i shows she does not like me! If it shows that i have to replace the screws and motor the machine will be  new. Playing the lottery looks like my only hope.


Best regards


Dropbox z movement :https://www.dropbox.com/s/1lvwdd7wee6k7c1/20160428_114613.mp4?dl=0

Ok what to do to be sure is,
Move the axis one way, by maybe 1mm,  with the gauge against it then move it the opposite way by the same amount and see if it returns to zero. If it does then there is no backlash.

You have relatively course pulses per rev due to the linear scales only being 0.005mm resolution and it could just be the way things will be.
A servo does not sit stationary like a stepper motor would, it moves back and forth a small amount to keep to the position. With good tuning and a highish resolution encoder you would see no movement as it would be so small but it will be moving.

I think your tuning is still not great, I think you will need to do the auto tuning at a much higher speed, I did mine at 100%. I aso had to fine tune the servo tuning after I did the AutoTune as it was fairly close but not as good as I liked. It was a long time ago I did the tuning so maybe the Auto Tuning has improved since the early days.



Hood

When i finish pid tuning and the try the axis calibration, then i get different steps per unit. I accept the steps per unit and i start again the pid tuning with the new value of steps per unit. Is this right ? Or im doing it wrong ?

Thanks for the previous answer will try to do this today.


Regards

I have never used the axis calibration as I prefer to work out the steps per unit from the mechanical data. The calibration will only ever be as good as you can measure, working iot out from known values will be as accurate as your hardware.
Hood

I had a loot to do these past couples of mots and yesterday i got back to retro lifting the machine. And here i have a new problem, i have connected a few buttons and  now i have a button for go to zero. And when i joog the y axis to a point lets say 200+ and i push the button go to zero and before it reaches the zero i push the stop button. The y axis starts to move back and forth like in calibration and it does not stop. Also the y coordinates stay put . The don t move at all. If i don t push stop on the machine it moves normaly to zero.

How have you set up the button, is it OEM Trigger or Brain or Macropump ?

Sounds like you may have the input duplicated in other scripts or brains or i/o.

Hood