I have an Avid CNC Pro 48x48 using Mach4 (with an ESS) and I'm looking to add a diode laser into the setup.  I already have the stock 2.2kw spindle.  It's my understanding that the PWM control is already reserved for the spindle, is there a way to ALSO control a separate laser, or would I just have to physically switch between the two?  The laser accepts a PWM/TTL signal.

Unfortunately there is only one PWM signal available so I physically switch between Laser and Spindle.

Tweakie.

Ah, bummer.  Do you just have two different profiles setup then?

Ah, bummer.  Do you just have two different profiles setup then?

I am able to use the same profile.

Tweakie.

I use the spindle and a laser controller. They share the same PWM port. While I have the capability, I rarely use the laser power control. I many vary the feed speeds to get the desired effect - Slow gives more power / fast gives less.

I have two toggle switches on my machine. One to turn on the spindle and one to turn on the laser. I only turn on the one that I am using at the time. I don't have a reason to have them working in the same program. I use the same profile in M4 for both of these.

I have also rewritten my CAM post processor to take out all of those pesky Z axis moves so it does not defocus my laser while I am running a G code file for the laser.

I love the laser. I purchased one from L-Cheapo - 3W. It is solid state and will cut (thin stuff) or burn (cutting boards etc). I have not bought a gift in quite a while 
They have a new 10W solid state laser that will cut thin stuff. I may have to give myself this for X-mas.