Benbox Laser Machines/CO2 Lasers/3D Printers

Software => LaserGrbl => Topic started by: poppen03 on April 25, 2019, 02:20:37 PM

Title: No Laser Control- Help
Post by: poppen03 on April 25, 2019, 02:20:37 PM
I just got a Chinese 3w laser engraver kit. No version info is shown on the board, but I'm told it's an older version. I flashed the board with GRBL 1.1 and I'm trying to use LaserGRBL. I have control over the motors. The laser turns on (at power up) at a low power and stays on. I have tried checking and unchecking the PWM box in the settings, changed the laser enable mode in the configuration from 0 to 1, the spindle max to 255 and spindle min to 0 and tried sending individual M3, M4 and M5 commands. Nothing has any effect. The developer of LaserGrbl has been very responsive, but we still haven't found a solution.

What else can I do to get the laser to respond to commands?
Title: Re: No Laser Control- Help
Post by: nottingham82 on April 25, 2019, 02:29:39 PM
That is an older design. It has two buttons on the board the left button is the power button. The right button is the low-power laser button. It is so that you can turn the laser on low-power and adjust the focus. It sounds like you're low power button is on. With the low power button on you have no control over laser power it just stays on at a very low level. You need to turn it off if you want to control the laser
Title: Re: No Laser Control- Help
Post by: poppen03 on April 25, 2019, 02:33:00 PM
Thanks, but I have tried with the button in and out. What else do you suggest?
Title: Re: No Laser Control- Help
Post by: ggallant571 on April 25, 2019, 03:06:26 PM
You need  the Arduino D11 connected to the gate of the MOSFET. Notice the 3 holes under the Nano. Mine has a 3-pin jumper. I think we can see the  trace from D12 going to one end. I suspect D11 goes to the other and the center goes to the transistor.

Title: Re: No Laser Control- Help
Post by: Zax on April 25, 2019, 04:33:02 PM
The solution is to use T2Laser with Grbl 1.1e Non-PWM firmware, or you could replace the controller board.
Title: Re: No Laser Control- Help
Post by: poppen03 on April 25, 2019, 04:42:16 PM
ggallant571 -Thanks for your reply. To be clear (sorry, newbie here) i would connect the center hole to one of the outer connections (the D11) and leave the D12 unconnected?
Update: I just tried the above with no change.
Title: Re: No Laser Control- Help
Post by: ggallant571 on April 25, 2019, 08:33:36 PM
That would be my guess. Zax is more knowledgeable about these controllers and he did not mention adding jumpers. Do you have an Ohm meter to verify the connections?
Title: Re: No Laser Control- Help
Post by: Zax on April 26, 2019, 05:11:00 AM
It's hard wired to D12, you are just shorting the Nano D11/D12 by doing that - not the best idea. You could start chopping pins / traces but why, just use my software and non-PWM firmware and bingo it'll work.

The alternate option is to replace the board and then you can use standard firmware and whatever software you choose, but T2Laser is still the best  ;D
Title: Re: No Laser Control- Help
Post by: poppen03 on April 26, 2019, 09:33:12 AM
Thanks, I will try T2 this weekend.
Title: Re: No Laser Control- Help
Post by: ggallant571 on April 26, 2019, 11:29:26 AM
As long as D12 is set as an input it will not be a problem if they are connected.
Title: Re: No Laser Control- Help
Post by: Zax on April 26, 2019, 12:32:13 PM
With these older Grbl 0.8 boards the MOSFET is connected to D12, so using Grbl 1.1 default that's defined as Z-limit with internal pull-up. Now you see why the laser is always ON!

If he connects D11 to D12, the D11 PWM output is still not going to function as D12 is pulled high.

Using my custom firmware will resolve the issue with T2Laser as it also enables a post processor on the G-code. It probably won't work correctly on other software.
Title: Re: No Laser Control- Help
Post by: ggallant571 on April 26, 2019, 12:40:55 PM
Thanks for the explanation. Sounds like he could build the firmware with D12 set as a normal input.
Title: Re: No Laser Control- Help
Post by: poppen03 on April 26, 2019, 06:22:59 PM
Well, I tried T2. It uploaded without any problems and I was able to control the motors, but I still have no control over the laser. :'(
Title: Re: No Laser Control- Help
Post by: Zax on April 27, 2019, 03:43:05 AM
Did you install Grbl 1.1e Non-PWM firmware and make sure the post processor was set to Laser D12?

Those 2 steps will make your machine work correctly.
Title: Re: No Laser Control- Help
Post by: ggallant571 on April 27, 2019, 07:33:24 AM
Assuming that the switches, MOSFET, cables, & laser are working!!!
Title: Re: No Laser Control- Help
Post by: poppen03 on April 27, 2019, 08:33:49 AM
I did install 1.1e. How do I set the post processor to D12?
Title: Re: No Laser Control- Help
Post by: Zax on April 27, 2019, 08:34:22 AM
We know the laser works but yes it's possible he used the "self destruct" button or what they call the "weak" laser button too long and the MOSFET is shorted.