Control K40 GRBL after opening satey door without resetting

I have an OMtech K40+, I understand the controler is GRBL.
When i connect it to my PC i have to press the reset button on the machine and type $x in lightburn.
This has to be repeated every time lid opens (it has two sensors to stop the laser if the lid opens).
I am very happy with the safety , knowing the laser wont fire wit the lid open. But resetting and sending $x all the time when aligning a workpiece is not convenient. Can it be changed safely to only stopping the laser, while keeping other functions active. Or set it up so all connections are restored automatically when the door is closed again (accompanied wit a reset if necessary) .
sending $x is mostly annoying when setting up for a material test, as you have to close the test to send the command and configure the test all over again.

I have not made any modifications on the machine yet , so i will need quite basic instructions

Has it always behaved like this?

It depends on how this machine’s interlocks are wired.

Normally lid interlocks interrupt the LPS control and only shut down the laser.
Perhaps your machine also has a switch wired to the controller to stop motion.

I would:

  • Trace and document how the lid switches are wired. One switch may go to the LPS and other to the controller.
  • Override one of the switches while the other operates normally. Run the job and see if you can isolate what they do. (wear eye protection!!!)

If there are two switches and their operation is isolated you could bypass the one that stops motion and kills the job. DO NOT override the one that interlocks the laser!

I would implement some way that when the motion switch is bypassed the lid cannot be closed. That way you have to remove the bypass when running the actual job and closing the lid.

If indeed there is a separate switch that stops motion you could connect that switch’s wiring to an ESTOP switch that is positioned outside the covers for emergency operation.

2 Likes