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Author Topic: Mach3 only sending one PWM Value HELP PLEASE!  (Read 1927 times)

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Mach3 only sending one PWM Value HELP PLEASE!
« on: March 05, 2017, 10:09:29 AM »

I have searched everywhere and can't find an answer.
when I set a S18000 The Spindle Speed DRO indicates 18000 but the RPM DRO indicates 14000.  The spindle spins up to 14000 RPM on the VFD display.  The problem is Mach3 will not spin the spindle above or below 14000 RPM no matter what S value I enter. It i like it will only send one PWM value

The Spindle Pulley is set to Min 1500 Max 18000

Ports and Pins / Spindle Setup:  Motor Control Use Spindle Motor Output PWM is Checked.  PWM Base Freq = 50  Minimum PWM% = 0

Ports and Pins / Motor Outputs: Spindle - Step Pin# = 14 Dir Pin# = 0 Dir Low Active = X   Step Low Active = X ( I have checked the Step Low active and that had to effect)

Motor Tuning Steps Per = 300 Velocity = 60 Acceleration = 1  ( I have tried multiple settings here per various threads and forums.  Changes had no effect)

Plugin Controll Main Config: ESS-M#-160630-U4F1b  PWM Checked Base Hz = 50 (I was advised the G540 expects the Base Hz to be 50) 

Smooth Stepper ESS:
Gecko Drive G540:
Huanyang HY03D023B:
3Kw 18,000 RPM Air Cooled spindle

(All Wirsing has been confirmed to be correct.  Oscilloscope shows good square PWM signal output)

Everything else works great.  Mach3 Turns Motor on and off but will only get one speed.
Attached is my Profile



Re: Mach3 only sending one PWM Value HELP PLEASE!
« Reply #1 on: March 05, 2017, 02:28:50 PM »

As I am eagerly awaiting some thoughts on my post, I was tinkering and decided to see what voltage is coming out of my G540 for the analog VFD.  It reads 0 Volts DC until I hit restart in Mach.  Then it reads a constant 7.35 Volts DC even before I have started my Spindle or even entered a S Value. 

FYI Reading Pins 7 and 8 from G540.


Re: Mach3 only sending one PWM Value HELP PLEASE!
« Reply #2 on: March 05, 2017, 03:12:48 PM »
One more thing I just realized.  When I enter a S18000 the Speed DRO reads 18000 but the RPM DRO reads 14000 as I said before.  But when I hit the Reset button a few times the RPM DRO will finally get close to 18000.  Also if I do a S9000 the RPM reads 7000.  I did the math.  Every S value I enter the RPM DRO gives me about 33% lower RPM readout. The DC voltage is still at 7.35.  Dint know if this helps troubleshoot.  
« Last Edit: March 05, 2017, 03:14:23 PM by RobWazam »

Offline Jeff_Birt

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Re: Mach3 only sending one PWM Value HELP PLEASE!
« Reply #3 on: March 05, 2017, 07:42:24 PM »
On motor tuning for spindle:

Steps per = 1000
Velocity = 60
Acceleration = 1000

These are the correct settings for the SmoothStepper, changing these to other settings than this will not help (apart form the acceleration setting). The Acceleration setting of 1 will give you a very long acceleration on the spindle speed. I would also suggest setting the minimum pulley speed setting to zero. When it is not zero Mach can do some strange scaling the PWM output. Your VFD is set to a minimum speed of 1500 anyhow.

When you are monitoring the square wave signal sent form the SmoothStepper to the G540 first try S9000. This should provide a 50% duty cycle square wave. If you then enter S18000 you should have a 100% duty cycle (flat line), entering an S0 would give you a flat line of other polarity. If you get the correct duty cycle at the DB25 pin of the plug connecting to the G540 then the fault is with the G540 itself.
Happy machining , Jeff Birt
Re: Mach3 only sending one PWM Value HELP PLEASE!
« Reply #4 on: March 05, 2017, 09:59:28 PM »
Thanks Jeff,  Always a great help.

Double checked the settings  they are as you suggest.  

So I contacted everything to my scope.  When I enter s9000 I get a 50% duty cycle.  go to 18000 and a 100% / flat line.  So, I suppose it is the G5490.

But one more really curious thing.  When I enter S9000 or any value I have to hit the reset button (between the up and down arrows in the spindle speed section) several times before the RPMs go to the correct speed. I can see on the scope the signal is changing as the RPMs get closer to the entered value.

Whats up with Mach that is will not start at the value entered without hitting the reset multiple times?  


« Last Edit: March 05, 2017, 10:03:30 PM by RobWazam »