Custom GUI models

I have been having some problems with the pid.0.maxoutput, pwmgen.0.scale and pwmgen.0.offset. I have a manual finetune adjustment on my spindle VFD controller that states that I should set it to be 100%RPM at maximum duty cycle.

Should .maxoutput and .scale be my 100% spindle rpm?
Would my manual speed adjust pot take the place of the offset value?

I am going to add some more magnets to the spindle to ballance everything out. I have not done it up to now because it will fubar my indicator, but having it on the controller screen is more valuable anyway. I just wanted to have it installed to verify the rpm vs the measured rpm.

Here are my Config files.

From here there are several things that I am trying to figure out. I now have 4 pulses per revolution of the spindle. This has been verified by the stand alone tachometer that I have on my machine. But with this configuration, the input needs to be 2.5 in order for the Display RPM to be kinda right. I have verified the physical RPM with a hand-held tach.

The first thing I need to fix is this error, does anyone see where it could be coming from?

Edit: Almost forgot. Debian Wheezy linuxcnc 2.6.5 G540 controller

andypugh wrote:

I am concerned that you get "roughly" three pulses per rev. This is a computer and digital signalling, there shouldn't be anything rough anywhere.

This is 99% of my problem, I am sure. I just do not see where the encoder input signal is being modified, other than the scaling factor for the number of pulses per revolution. Also the error appears to be non-linear, and the error changes with command rpm. The the 2.5 factor that I said earlier will put it spot on at 1200 RPM, but I am off by ~150 RPM at 400 and 2500.

I probably just need to sit down and really simplify the main and custom_postgui hal files, and slowly build it back up line by line. I was just hoping that there would be a more simple plug and play solution because closed loop spindle control is not exactly a rare thing for CNC machines.