Tuning Steperonline A6 Servos

Hi,

I have a general question about tuning the Stepperonline A6 servos. 
I set up the servos using the auto-tuning feature.
I’m quite happy with the results.
However, I’ve noticed—especially when probing in the range of 0.01 mm and 0.001 mm—that the servos respond very imprecisely. I’d like to make them more precise.

How did you handle this?

I’d also use Stepperonline, but I can’t get a connection to the servos with it. 
 

Define very imprecisely +- 1mm?

No, not that.

So, if I tap just once, for example 0.1 mm, the axis moves 0.09 mm and it takes about 1-2 seconds for it to adjust.
It's exactly the same at 0.01 mm.
At 0.001 mm, I have to tap several times before anything moves, and it takes quite a while for the axis to adjust.
I did some calculations:
17Bit encoder and 10mm spindle:
1mm = 13107,2 inc = 35,38°
0,1mm = 1310,7 inc = 3,5°
0,01mm = 131,0 inc = 0,35°
0,001mm = 13,1 inc = 0,035°

The A6 should easily manage that.I don't think autotuning alone will be enough.
You'll probably have to adjust some settings in the driver.
 

Some booster parameter for micro increments?

That's exactly what I'm looking for. Perhaps someone has already made such adjustments to the driver and can say which parameters need to be adjusted.

Verify Pr0.04 with inertia identification.
Zero Pr2.22 and Pr2.23.
Raise Pr1.10 to ~500, see if small moves land correctly.
Bring Pr1.12 up in 10-point steps with Pr1.13 ≈ 50.
Measure breakaway torque per direction (d04 monitor) and set Pr6.08/Pr6.09.
Only then, if still imperfect, enable Pr2.50 (ZTC).

Thanks for the help,
I'll go through this step by step and get back to you 

If all you did was autotune, you aren't done.
You need to set the feed forward. Also set the in position error allowance.

What could be happening is that 2 or 3 microns is still within the drives set error, so it just doesn't move.

I'm at this step to. But I feel like it's been worse after the autotune than it was before.
That software is such a mess that I regret not going the Leadshine way.
I also have a slightly noisy Z axis servo but I can't find the gain parameter... Any clue ?

Oh, I almost forgot – I wanted to let you know if I succeed.I’ve been gradually increasing the C00.05 stiffness parameter.