I have a diy laser with UNO/CNC shield running grbl 1.1h. Its been running fine but installed x- and y- endstops on the front left positions with a 2mm pull off. These were configured and working properly but the 0,0 point was in the upper right. I followed the setup guide and set $10=0 and I also set G10 L2 P1 x-660 y-660 which shifted the 0,0 to the front left. If I home it and check the coordinates they show 0,0. If I ask the machine to move G0 x100 y100 all works properly. I set up a job with the origin point in lower left and it drives - direction on both axis and crashes. I have disabled the endstops after fighting it for a few hours. Any ideas why it would go negative direction on a job but not while jogging?
A few background questions:
- Did you compile grbl yourself or is this a pre-compiled installation that came with the UNO/CNC?
- How are you homing if you have disabled the endstops?
- Where do you have the machine origin set in device settings?
- What are you using for Start From in Laser window?
Can you run these commands and post results here:
- $I
- $$
- $#
- ?
Can you attach a screenshot of your full LB window as well as a sample .lbrn file where you get this behavior?
Lightburn/grbl is not configured properly is a safe bet.
Since you changed āhomeā, did you change āhomeā in Lightburn?
Where does your head show in Lightburn, relative to the object?
What āStart Fromā are you using?
I understand the āJob Originā is bottom leftā¦
Sometimes a screenshot helpsā¦
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sorry for the delay in responding. I built the laser engraver for my neighbour but he has been very busy engraving his cutting boards with the Christmas rush. I will get the screen shots over the next couple days as things settle down. We are using it without the endstops which I have just disabled in in grbl and lightburn. My unit has not been modified for the endstops yet and is in my unheated garage (-32c this morning). Before someone asks, we have both purchased separate licenses of Lightburn.
Iām sure when you get the ārightā bit set, it will function properlyā¦ sooo
When you added end stops, did you use the āhomeā the machine has been using?
What Iām asking is if you changed it to where you would ālikeā to have it home, as compared to where it āoriginallyā homed?
Since you donāt have end stops, where do you place the head when you power it up for a āhomeā position?
Two things to checkā¦
First is the āStart Fromā and āJob Originā settings.
The second is how are you configured in the āEdit ā Device Settingsā for āoriginā
You answered the $I question, probably with the version of grbl you are running, āgrbl 1.1hā. The $$ gives you your configuration, which can be read from āEdit ā Machine Settingsā, along with a text translation of what they do. Suggest you save a copy if you havenāt already. You may need to go back to a known starting place, so keep a āfactory freshā configuration somewhereā¦
It takes 2 screenshots to get the whole thing on my machine, but it is much more clear to digest. I donāt have to find what $10 is used for via some other source to know itās the āStatus: Position reportingā.
My guess, is that you might need to be in āabsolute coordsā mode in the āStart Fromā boxā¦
Here is what the Machine Settings screens should look like. This is my Xmas grbl, so have no idea about itās values being legitimate.
For the $3 entry, you have to add up the bit pattern for the proper value
In the following, you will notice that $3 is referenced in 3 places accounting for all 3 axis directions.
Iām sure itās just not configured properly, so hang in thereā¦
I am going to drag my machine into the house and set it up the same as my neighbors and test it here. That way I can take screen shots and try thing without disturbing his work. It will also help me learn the lightburn a bit more as I was working in lasergrbl and laserweb4 for my needle cutter/laser work. I am going to see if I can use the lightburn with the foamboard needle cutter as well. The needle cutter uses the pwm pin to drive a servo.
This is a neat idea. Is the servo variable speed? I assume for a needle cutter youād always want the needle to be spinning at the same speed. You may be able to simulate this with āConstant Powerā in cut settings. Or else you may need to turn off āLaser modeā in GRBL. $32=0.
The needle cutter uses a rc brushless motor and flywheel much like a sewing machine needle and the servo adjusts the height of cut and can vary it for full or partial cut. Check ERC Timsav on youtube.
Iāve seen these videos and kits. Pretty neat stuff.
I setup my machine with endstops and the same grbl settings as the neighbors machine and it worked fine so I will check his device settings in Lightburn. I may try setting up his machine from scratch again to make sure it was done properly. The only setting that I didnāt set on mine was $13=1 as he uses inches. I wasnāt able to test the needle cutter as It required a fork of GRBL 1.1h with servo control which changes the pwm frequency and I didnāt want to though a variable into the testing. I will load up a second uno with the servo version and test later.
Irrespective of whether or not he uses inches from a design perspective, this should be set to mm as thatās how the communication from LightBurn to the controller is expected to occur.
thanks I will test that on mine and see if thatās the problem
Also, if you have the endstops connected and homing, you should not have to set an offset and you should be able to use machine position ($10=1 or $10=3).
I had mine working fine but at one point I screwed up and it was going negative so did some checking and somehow my g54 settings were something like 17600. I zeroed them with the G10 L2 P1 X0 Y0 and then set them to -660 on both axis and it worked fine. Donāt have a clue how that got changed. As for the servo based needle cutter, I got it working by setting up a second device and used the M3 driver even though I am using 1.1h_servo for firmware on my board. When I used the M4 I would get the servo dropping but would not raise when travelling. So its just a matter of selecting which device and change the $32 setting for laser or needle cutter. Now to learn the finer points of the software!
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