haha, yeah, i'm like 99% sure i can have configuration issues:) There are so many variables to account for in setting up mach 3 that it's almost a guarantee that some issue will come up. I'm going to work on trying to resolve the issue this weekend, test out the output PWM from SS, compare it to the scaling out of G540, check noise on the control lines to the KBMM, etc.

The tach sensor is on the spindle itself, motor is connected to the spindle via a toothed belt via a 0.4 reduction. I also verified the index rpm was correct with a laser tach, it was within a few %.

I'm going to go through my configuration this weekend too, to make sure i didn't miss anything, and i can try to post some screenshots of the config screens.

Just as a side note, the closed loop spindle control does or doesn't work with SS? In your setup, if it does work, if you put a load on the motor, how long does it take Mach 3 to respond and bring the speed back up?

If you have the sensor on the spindle make sure you do not have anything but a '1' in for any of the pulley ratio boxes.

Just as a side note, the closed loop spindle control does or doesn't work with SS? In your setup, if it does work, if you put a load on the motor, how long does it take Mach 3 to respond and bring the speed back up?

This is the question and I'll be following this thread closely.

maddios, your curve is WAY worse than mine, but a solution to yours would seemingly help me. I don't know what to change or where, to change the linearity of this PWM spindle with SS. I also don't know if I can fix this somehow in my VFD settings or in the PMDX-125/107 combo.

I've never sat down and tried to figure it out. I know my index sensor is feeding Mach the absolute right RPM, but the commanded RPM is not what the index sensor is reporting except at one spot in the curve.

If you have the sensor on the spindle make sure you do not have anything but a '1' in for any of the pulley ratio boxes.

Hmm, a 1? I put a .4, what does this number mean? I'll try that tomorrow night.

In your case you have the tach sensor mounted on the spindle, so there is a 1:1 correspondence between the tach signal and the spindle speed. If you have a machine where you mount the tach sensor to the motor instead then Mach needs to know the reduction ratio between the motor pulley and spindle pulley. Let's say you had a 2" pulley on the motor and a 4" pulley on the spindle; that gives you a 1:0.5 ratio. So, for every one turn of the motor the spindle rotates 1/2 turn. You would then put in 0.5 in the ratio box for that pulley set.

Make sense?

Hm, yes it does, thanks, I will try that and maybe it'll help with some of my issues. Mach manual is very vague when it describes what to put in those fields, took me forever to realize that the spindle max is the 100% side of the pwm requested.

Alright so seems like my G540 was bad. I just tested my SS with a scope and the pwm output is perfect, however looks like the g540 has degraded further and now no-longer outputs anything. I'm feeding it a known good voltage with a 9v battery and seeing zero output from pin 8.

I'd still like to get my Mach3 to operate closed loop though, as regardless of whether or not I have a linear setup, the motor still needs to have higher PWM when load is applied to increase power. When I'm back up and running I'll try again

I fiddled with the settings in my VFD, Hitachi SJ200. I got the curve better. Now it's right on at the high end and off more and more as it goes lower. I see another setting in my VFD I may play with, a setting that seems to adjust the bottom. My guess is once you get your PWM coming out of your BOB correct then tuning in the VFD may get it pretty close.

I, too, would like the closed loop thing to work, that would add icing to the cake!! I'll be watching this for sure.

I'm actually using a DC motor controller KBMM-125, it's a 16A 90VDC controller. There's really no adjustment on this thing other than max current output, accel/decel time and min/max speeds.