Set up using AMC AB15A100 drives, brushed DC motor Prototrak Plus with Encoders

I think you may have adjusted FF1 in the wrong direction. (A negative error on a negative direction move is the same as a positive error with a positive move.)

As to starting with the Y, I don't think I'd start with the X settings, but something a little more conservative. Maybe half the P and D. FF1 and FF2 will be question marks. I don't think they will be the same as X.

I'd set set the deadband = 0.00005 instead of 0.000001.

Todd, This pics are of DeadBand only. The error looks lower with DeadBand=.00001, that was the reason.

I set .ini MAX_Acceleration to 1.2 from 2.5 for "Y" axes.

Many thanks.
 

Setting it to less than one encoder count also doesn't quiet the at rest dither either. Notice the little bumps in the output and error before you begin your move. Usually the small loss of precision (one encoder count) is more than made up for by the resulting smoother operation.

Todd, thanks! I have tried several trace settings, I see the bumps you talk of, the DeadBand .00005 is the minimum setting, any less does nothing for trace. The attached pic has slightly more error, (total around .0007", add the top & bottom maximums), if this is correct I am ok with that.
I worked some on the "y", nothing to show.
Many thanks!

What does setting FF1=2.11 look like?

Todd, thanks. This is the trace you asked about. It does look nice.

Many thanks.

Didn't change enough, try FF1=2.12.

Todd, thanks! Attached are a pic of before & after, I have not studied them.

Many thanks.

Todd, This is the 1st pics of the "Y" axes, I'm looking for suggestions. The .hal Max_Acceleration is at 2.5 (same as x axes).

Many thanks.

Are you sure the acceleration is set to to.2.5? It doesn't look like it is. (Don't forget you have to shutdown Linuxcnc, edit and save, then restart Linuxcnc before edits to the ini file take effect.

Are you sure you changed all of the correct lines to change the acceleration of the Y-axis?

(Otherwise it looks like the Y could use more FF1.)