GearHeads Forum

Back in Mar 2020 I started a post wherein I questioned PWM and M30 problems.

I'm happy to let you know that I figured out the "double M30" problem we discussed already. In the Edit Pro/Epilogue config pulldown there was an Epilogue line of text showing an M30 and some comment that I can't remember just now.    I deleted that Epilogue text string and all is good.

The PWM is still bothering me a bit.  When I issue an M3 command and watch the PWM output with my o'scope I see that there are PWM pulses output from the Pokeys57CNC at 1% of the PWM freq BEFORE I even hit the fire button or move an axis.  This happens regardless of the PWM frequency. It just happens to light my laser at the lower PWM freqs and I noticed it lites my diode because my control board is spec'd at between 500 and 1KHz.  When I get above 2KHz my control board doesn't light the laser (that I can see). 

My tickle is set to 0 (even went negative number with no difference) as you recommended yet the Pokeys board still outputs a 5uS wide pulse (at 2Khz PWM freq).  Why?  Min power is set to 0. Max is set to 97%. 

Is there a way to set a minimum output in the Pokeys board that I haven't discovered?  I'd like to set to zero.

I'm chasing this because I'd like to run my PWM freq at the laser control box spec of 500-1000Hz without the dang laser lighting up when I issue an M3 command alone.  Also trying to improve my raster engraving of lighter gray parts of my image.  Different discussion/investigation.  Trying to optimize machine first and this "1% always on" bothers me.

Mark

A couple of other interesting things I've noticed.  Some of the Engine/Planner Config parameters don't seem to change my observed results at all.

The PWM Period does in fact change the PWM frequency observed on my scope.  So that's good news.

Now the bad news.

Changes to the MinPWM(Tickle), MaxPWM, and MinPWM(PowerOn) have no effect on my laser function. I set Tickle to 10.  No changes seen.  I set MaxPWM and MinPWM to 50 and 10 respectively.  The PWM waveform on my scope show expected pulse widths for values higher than 50 and also lower than 10.  Confirmed by my diode current meter and visual observations of the light intensity.  So it appears that these limits are not affecting my Pokey board output signal. Something else is controlling max and min power.

Next, I stumbled around in the SpindleLib-Laser script.  Just looking.  These lines below from it seem to me (uneducated in programming) to set the max power to 100%, pwm freq to 5KHz and sets the channel to 4.  These are contrary to what I'm trying to use: channel 2, max power at 97 and 1KHz for PWM freq (0.001 period).  Do I need to edit the script to use my values.  (the ones I set in Engine/Planner Config table)

p = Profile("rtPWM");
global LaserAxis = p.GetInt("Axis",8);
global LaserMaxPower = 100;  //max power = 100%
global LaserPWMPeriod = p.GetFloat("Period",.0002); //for 5khz tickle 
global LaserPWMChannel = p.GetInt("Channel",4);

That's enough for tonight.

Mark

Hi Mark:

I will do a check to see what might be going on..

As I recall, the lines below were necessary just to initialize the scripting.
The second part as in the line LaserAxis = p.GetInt("Axis",8); translates to
LaserAxis is ( Get the value stored under "Axis" and if there isnt one, use 8.)
So the setting for something like PWM tickle..should override the default when its set.
Ill check to see why it may be giving you a minimum instead of zero..


p = Profile("rtPWM");
global LaserAxis = p.GetInt("Axis",8);
global LaserMaxP ower = 100;  //max power = 100%
global LaserPWMP eriod = p.GetFloa t("Period",.0002); //for 5khz tickle
global LaserPWMC hannel = p.GetInt("Channel",4);

l

Thanks Art.  This morning I edited the script and changed those values. I noticed no difference in my observations.  So I changed then back to original.

Mark

Any news on this front?  Any way I can help?

Sorry Mark:

Life intervened and I neglected this. I will test rigth now and see what I see. Ill post shortly to tell you what I find.

Thx
Art

Mark:

  I just tested on my laser and I see your correct. The PWM minimum was being set to 1 no matter what.
I just uploaded a fixed file. The configuration setting will now work including zero.

Thx
Art

No worries Art.  I understand completely.  I live it too.

I'll go figure out how to get the fix just as soon as I can get to it. 

Hopefully tomorrow.

Mark

Art,  I downloaded the most recent Coninstall.exe file 4.3.0.347 Ver 3.7b this morning from gearotic.com/downloads.html.  I selected Auggie CNC Addon.  Ran the executable and took the defaults for file location and allowed it to overwrite the current files.  Successfully I think...

Now for the bad news.  I ran Auggie and had the same results.  PWM set to 500Hz, Tickle 0.  Issued M3 and observed Axis 8 went to 1 (some bouncing around) immediately and my diode emitted light. 

The only things I can think of is that I need to download your current development version of Gearotic or maybe I should have selected the patch and release notes.  I didn't want to just shotgun this and mess up my system before I checked with you.  What have I done wrong? 

Thanks,
Mark

Mark:


Sorry abou tthat, the update is proper on the site but for some reason hasnt propogated. Use this link to get it while its sorted out..

http://gearotic.com/ConInstall.zip , the version you should get is 3.7d , not b..

Art