Hi Peeps, So I got my laser all programed in mach3 and it works great. However...the only thing I can't figure out is the power control to the Laser Head. I thought the spindle speed control would do this for me but no. My Post Processor is a Jtech  and the laser on command is M3 S12000 it turns the laser on full power. Any suggestions on how to control this to get less power?

Are you using the LPT Parallel Port to control your machine or are you using an external motion controller ?

Tweakie.

 I have a DB25 breakout board between stepper controller and and gecko stepper driver. I am using Pin 17 & 1

Mach3 will turn ON/OFF an Output# using the M3 command but it is slow so the M11/M10 commands were introduced to speed things up. The Output# used by M11/M10 or M3 will not contain the PWM signal - this has to be on another Output#. To get laser ON/OFF switching at variable power settings (determined by the S### command) it is necessary to gate two signals and this I have tried to explain in this thread - https://www.machsupport.com/forum/index.php?topic=12444.msg265104#msg265104

Hope this makes sense.

Tweakie.

Hi Tweakie,  here's where I'm at right now. I set up a new profile for laser and followed all of the settings you shared in one of your links.  The laser will run a program and work as it should meaning it will stop /start burn in the places that it should.  Zed is stationary thru out.  however with any M3 s### commands I give laser, power strength will not change even though DROs in the spindle window will change to my commands laser remains full power. I must be missing something simple somewhere. im attaching a wire diagram in hopes to shed some light.

Hi John,

As mentioned in my previous post – you need the PWM on one pin and the switching signal (M11/M10) on another pin. The PWM is variable by the S### word and turned on by the M3 command.
In operation the PWM is turned ON and left running. It is then applied to your laser TTL input by the gated PWM/M11/M10 signal so you need to construct a small circuit (as I described in my previous post) to achieve this. At the end of the job the PWM is turned OFF by the M5 command.

Tweakie

Hello again Tweakie,   The small circuit board that you mentioned is it available to buy somewhere or can you tell me exactly what those components are? if so I can try to find the parts and build myself.    Thanks

Hi John,

I suggest you use one 74LS00 NAND gate (the configuration differs dependant if you require TTL(L) or TTL(H) output) as shown in this post https://www.machsupport.com/forum/index.php?topic=12444.msg265104#msg265104 (you may also need a 7805 voltage regulator if you do not already have +5 volts available to power the NAND).

The alternative shown in this post; https://www.machsupport.com/forum/index.php?topic=12444.msg194503#msg194503  does not require a dedicated +5 volt power source but it is only suitable for use with TTL(L) laser input circuits (the necessary +5 volts is derived from the laser controller input as described here; https://www.machsupport.com/forum/index.php?topic=12444.msg280468#msg280468 )


Tweakie.