Laser / Spindle Control Connections

I saw a post that was never answered with this same problem so I thought I would ask again in case I missed it.

I have the JTech laser and it is connected here:

Using the wiki I installed a relay to control my router and it connects here:


Problem is that running the laser sends voltage to the relay as well. Is this as planned?

I will be upgrading to a spindle and was wondering if I will still have the same problem?


PWM is an output that is enabled when the “spindle” is on. Laser/Spindle…as far as the grbl software is concerned…same thing. There is no second output for a laser vs spindle. You will have exactly the same problem - the machine really has no idea what you’re controller with that output.

Your best bet is to add a switch in the pwm line, and open the switch when you wish to use the laser.

Thanks. Would an A/B switch work you think utilizing just one of PWM connections and sharing it?