Hi there. I am currently wrapping up my first CNC lathe conversion from the trusty WM280V. I have the everything mounted, and all that is left is to set up the spindle control, the axis motors work perfectly. I have had little luck controlling the spindle speed with M03 & M04 codes, however they can change direction. As it appears, by either having the spindle PWM on either active low or high, I can have the spindle run flat out or dead slow, but with no change using gcode at all. For example I would use M03 S500, depending on the settings it will either be 2300rpm (Max) or 50rpm (Min). I have tried playing with the ports and pins settings on both Mach4 and the ESS with no luck. The test function on the PMDX107 does control the spindle, but the '30%' threshold runs a lot less than it should.

Does anyone have any ideas?

Thanks in advance

Joe

I have a 126+107+ESS+VFD (different motor though). Have you tested the spindle using the PMDX107 by itself? It should start the spindle then ramp up to speed for 30 seconds or so. If that doesn't work then you have a problem with your VFD programming or your wiring. If not then.. Mach4 should ONLY be setup for "Spindle Fwd" in the output signals. In your ESS setup you should have the "SPINDLE FWD" and "SPINDLE PWM" configured properly. Once I had it setup, I bought a cheap tachometer off Fleebay for around $15 that uses reflective tape to calculate the spindle speed for precise calibration adjustment on the PMDX107.

Hope this helps.

Hi, firstly thank you for replying so promptly it is much appreciated!

I do believe I had tried them before (I think it was mentioned on another post?). However, I thought I would try it again as it worked for you. Unfortunately I still am only able to run at max speed or min depending on whether the pwm is active high or low. I did try to change the pwm frequency in the .INI file as another forum suggested this, it didnt work (I have tried 1000, 900, 400, 100, 50 and 25 Hz). If I run the test function, as stated in the 107 manual, pushing the black button, the spindle fires up to max speed, then at the second click slows down, third it stops, just as the manual suggests. For this reason I do believe the VFD and wiring is correct. I have run a series of gcode lines ( M03 S200, M03 S500, M03 S2000) one at a time and the spindle doesn't change speed, and putting a multimeter on the 107 the pwm voltage is constant low or high depending on the pwm active high low setting.

Have you any ideas?

When you are running your test on the PMDX107, have your VFD set to display output frequency on the led terminal. Verify it is in fact starting from your lowest freq. setting to your highest. It does sound like VFD programming and wiring is correct. In Mach do you have your spindle speeds setup? In the config there is an option for Spindle. You must enter in your minimum and maximum spindle speed. If thats okay, then I would try uninstalling M4 completely and starting over from scratch. Just curious, is this a liquid cooled spindle?

don't set your active high or low in mach set it in ESS config

I have attached some photographs below showing the VFD frequency when the test button cycle is run on the 107. The last (5.6) is always on. Yes, I have the speeds setup in the first, so just 30 min 2300 max. So I guess try a fresh install?

So you mean in the mach outputs just have the cross no tick for the active high low?

A quick thought. Should the spindle be shown under the motors and mapping tabs with the axis motors?

More photos attached.

Hello Joe,

Your WM280V lathe uses a DC permanent magnet motor. This type
of motor along with the typical speed controller provided has very
poor linearity in the low speed range. The response that you see to
the test function built into the PMDX-107 reflects that. The best way
to cope with that is to adjust for the expected speed at 100% in
test mode and then use the Linearity.dat table in Mach3 to make
corrections for the lower speed ranges. While Mach3 can collect
this data automatically, I usually recommend measuring the motor
response and entering the data manually. At speeds above about
30% of rated speed you should achieve reasonable success.

Verification of maximum speed and data collection at other speeds
must be done without a Linearity.DAT file present in your Mach3 folder
in order to get unadulterated data.

To confirm proper operation of the PMDX-107 you can measure the
output voltage of the PMDX-107 between the Aout and Agnd terminals.
The voltage there will be a percentage of the voltage applied to the
Aref and Agnd terminals. At full speed the voltage on Aout should
be close to the same a the voltage on Aref. At 50% of full speed
the voltage on Aout should be close to half of the voltage on Aref.
These measurements should be taken using the built in test mode
or from Mach3 WITHOUT a Linearity.DAT table present in Mach3 as
the linearity correction will change them.

There are two other concerns in your configuration that you did not
mention.

First, you must have your Pulleys configured in Mach3 in order for
the S word settings to be meaningful. Mach3 uses this information
to compute the percentages for PWM by determining the ratio of
requested speed to the maximum possible for the pulley in use.

Second, the SmoothStepper has an unusual requirement in that it
needs an acceleration setting even though the spindle is not an axis.

Please see our application notes about using the PMDX-107 with a
SmoothStepper here:

http://www.pmdx.com/Doc/AN002_PWMSpindleSmoothStepper_02.pdf

Steve Stallings
www.PMDX.com

Steve M4

Oops, my bad.

The comments about the DC motor controller and it linearity problems are
still valid, but not my suggested solution.

To my knowledge there is no off the shelf solution in Mach4, nor do I know
how well the SmoothStepper works with PWM in the Mach4 environment.

Steve Stallings
www.PMDX.com