HURCO KMB-1 Control Update

Hello, This is likely the wrong spot to ask this question, but as its one of the first things I've machined using linuxcnc on the machine...

The profile I've machined is essentially circular and should be symmetrical, and the bore clocks in at X0,Y0.
issuing a G0 X0, Y0 gets me back over the bore and it repeatably clocks in.
The finished machined part has a Y offset of 0.2mm.
This may be a programming issue, but I have noticed a random Y -28.11 offset in the tool table for the tool used.
If that entry was doing what I thought it should, then the mis-machining would have been 28.11 and not 0.2. However, could this entry have caused the issue?
On a three axis mill, is there a purpose for the X and Y offsets in the table?
Thanks

By experimentation, the Y and X offsets can be entered pressing tool touch off with the wrong axis selected. On a 3 axis mill, as far as I can tell numbers in these columns are ignored.

Spindle Speed Control.
Now I have the spindle encoder in place, I set up a PYVCP read out for actual spindle speed, which agrees precisely with a handheld rev counter. Even registers  negative in reverse. so I believe the encoder is working ok in quadrature.
Problem is that I now see that the commanded speed and actual speed are way out, at s2000 I am seeing almost 3000rpm.
(The spindle speed override is at 100% in the GUI)

My motor has max speed of 3600 and the VFD outputs max spindle rpm of 3600 at 8 volts. Increased volts are ignored.
I've checked the relationship between rpm and volts between 0.24V(350rpm) and max speed, and it is linear.
I have tried changing the ini file [Spindle_0] OUTPUT_SCALE and this helps, but then the slower speeds are shifted.

So I think its clear the controller feedback isn't functioning, and I'm failing to see why.
I don't think I need super dooper speed accuracy, but I do want to be able to rigid tap.

Would an expert please cast their eyes over my attached config files and point out where I am being stupid 
Thank you.


 

I would make a couple changes in the ini file

OUTPUT_SCALE = 4500

(4500 is 10V/8V * 3600)

And initially I would try open loop
which means P,I,D = 0 and FF0=1

(FF0 should always be 1 regardless
of other PID parameters in a velocity-in/velocity-out
PID control loop like this spindle control )

Thanks Peter.
At high speed 3500 gets me 3400, but 300rpm ends up with 500
Also I have an 'oddness'
If I call for too big a jump in speed reduction, say from 3500 to 1000, an internal part of the vfd drops out the enable relay that is set by M3. If I drop the speed in smaller steps, this doesn't happen. (Probably one to sort out with a max rate of deceleration later. ) Acceleration from 0 to 3500 is ok.
I think for now I'd like to concentrate on getting the low speed more precise.

I have now looked at the pid.s values and see that there is no pid.s.feedback
in the hal this is fed from:-
net spindle-vel-cmd-rpm-abs which also has no value when the spindle runs.

So I have changed this to
net spindle-vel-cmd-rpm which is an active value of the current speed.

Nothing changes, so I guess have to set some of the PID values now?