Laser connected but does not "toggling" when running

(Mid Child) #1

I’m currently running LaserWeb4 on my laser engraver connected to arduino uno with cnc shield. The problem is the laser is continuosly on when running, meaning there isn’t any “toggling” and “pauses”.

I previously run my laser engraver on Benbox with their given hex file, and it works fine.
However the issue occured when I turned to Laserweb4, running on grbl 1.1f hex. With different version of hex file, the laser is connected to “SPINDLE ENABLE” on the Benbox hex file, while “Z+” on the grbl 1.1f.

I can actually control the laser on Laserweb4 by typing “M4 S50” and “M5” to turn on/off (no idea why the “laser test” and “laser off” button doesn’t work), but it just won’t do the toggling when running the .nc/image file. What can I do to fix this issue?

Thank you in advanced!

(Don Kleinschnitz Jr.) #2

the laser is continuosly on when running, meaning there isn’t any “toggling” and “pauses”.

By laser do you mean the laser beam or the entire machine?
What do you mean by “toggling and pauses”?

We need the following to troubleshoot:

  1. What kind of machine it this?
  2. Please provide a picture of your laser power supply (LPS).
  3. Provide a drawing of how the “L” pin on the LPS is connected to the LPS.
(Mid Child) #4

I’m running 2 stepper motors and a laser module on an arduino uno with CNC shield.

Regarding to the “toggling and pauses”, I’m actually refering to the event when there’s gap between 2 points during engraving, the laser would normally turned off during the gap and toggle on once it reaches the other point.

In my case, the laser would just stay on/off entirely, which it engraved along the path moving with the stepper motors, without “blinking”


(Don Kleinschnitz Jr.) #5

Oh this is not a K40 so ignore what I said above.

I would need a lot more information on exactly your setup to be helpful.

Did this ever work correctly i.e. is this a new build or something has changed?

(Mid Child) #6


It’s working when I used it with Benbox uploaded with their hex file.

Then I wanted to run my setup from a server, so I switched to LaswerWeb4 with grbl 1.1f hex file, but then the issue occured.

(Don Kleinschnitz Jr.) #7

I do not know Benbox.
Is the software all you have changed?
I would start by dumping the Gcode for both configurations and comparing them.

(Mid Child) #8

Yes sir, the hardware remains unchanged (if you don’t consider the changing of connection on the CNC shield for the laser which is either “Z+” or “SPINDLE EN”), the only difference here is the software (Benbox & LaserWeb4 as well as difference version of hex files).

I wanted to upload the hex file used in the Benbox, but it’s not allow here. What do you suggest so I can share it here?

(Mid Child) #9

There’s several links to download Benbox here.

(Don Kleinschnitz Jr.) #10

By hex file you mean the code that Benbox creates. Is it proprietary vs Gcode?

I do not use LW any more but what do you see on the LW screen that is to be engraved?
Post picture.

(Claudio Prezzi) #11

Please check which version of the CNC shield you have. The never once have swapped the Z-Endstop and Spindle PWM pins so you can connect the Laser TTL to Spindle PWM out.

(Mid Child) #12

I’m pretty sure it’s a V3 for the cnc shield.

I didn’t connect to the Z-endstop. Instead, I’m actually switching between, “Z+” and “SPINDLE EN” based on the different version of grbl.

(Mid Child) #13

It’s a .bmp image, so I can’t upload it here sir. Hex file are basically versions of grbl, it is proprietary with Gcode i guess, if not my stepper motors will not be moving along.

(Claudio Prezzi) #14

What do you mean by “switching”? Swapping the cable connection?

The situation is like this:

  • On Grbl versions before 1.1 the Spindle PWM output was on Arduino pin 12 and Z-Endstop was on Pin 11.
  • Since Grbl 1.1 pins 11 and 12 was swapped so that PWM is on pin 11 (which is PWM capable).
  • If your CNC-Shield connects Arduino pin 11 to Spindle PWM output, it is the new version.