Spinx1 to 7i85

Slow speed is off. Spindle is pulsating a bit at S1. In the hal configuration I can watch signals spindle-vel-cmd .0166, spindle-vel-pid .0169 and spindle-vel at .14 to .23 with a range of .3 to .5hz or so on the VFD. I set the min rpm internally on the VFD to .01hz. My open loop config gets me closer on the low end. How do I improve the low end rpm?

I think the mid range is good at S1765, the corresponding vel-cmd, vel-pid and spindle-vel numbers are now at 29.41,29.82 and fluctuating around 30. This is with FF0 set at 1.014.
The high range at S3555, 59.25, 60.07, vel fluctuating around 59. VFD at around 118Hz. Seems close enough.

Looking at the same numbers change as I ramp the spindle up/down I don't see the velocity overshoot. This is without I or P. The motor sounds unhappy with P or I introduced even at low numbers like .01. I haven't yet looked at it on the scope.

My current ramp up speed within the vfd is around 4 sec 0 to 3550rpm. The VFD internal PID parameters need more adjusting as well. Do you recommend leaving the ramp up speed as is or increase it and have linuxcnc do the soft start/ramp up? What is common practice?

I finally completed the x axis for this lathe and I'm getting back to configuring Linuxcnc. Sorry to resurrect this old thread, I need some clarification on lathe spindle rotation.
Looking at the axis gui, the CCW and CW spindle rotation buttons correspond to the spindle rotation in what view? Is the CW button rotating the spindle CW when facing the spindle or looking down the spindle from the back of the lathe? Traditional lathe with spindle on the left positive x towards operator.

Andy

Thanks. So essentially the spindle rotation on a standard lathe, forward is CCW when directly looking at the spindle/chuck, which is the same as CW when looking in the positive Z direction facing towards the tail stock. M3 is Forwrd(CW) M4 Reverse(CCW).
I made the mistake of setting things up reflecting the axis rotation buttons as in looking at the spindle. This is really rudimentary, it would be nice to have a diagram in the docs to refer back to.
If got this right, I need to reverse my spindle. What is the easiest way to reconfigure this? As is, my encoder count increases in M3 .
Will this convention be correct for c-axis work?

I corrected my rotation. I just changed the wiring to the vfd and reversed the encoder in the ini.
I'm trying to run some test programs. The machine hangs at g76. Specifically, line 102 (g76) running the lathe-g76.ngc program.
I know there is something off or missing with the spindle. What should I look at first?

OT-CNC wrote:

I The machine hangs at g76. Specifically, line 102 (g76) running the lathe-g76.ngc program.

I might be sticking my neck out a bit here But I had a similar issue and was advised that the encoder might be counting backwards so the G76 hung as it did not know that the spindle was up to speed. Also I think you need the S peram in the Gcode to be near the spindle speed you are using.
That was my problem. Thanks to cncbasher for the solution.