Hello! I am new to laser cutting so when I bought my own OMTech K40 and a Lightburn compatible memory board, I was really excited to get going. so I started off by homing my machine and everything went well until I tried to frame my project, and here is what it said: Alarm: Hard limit -X. I tried again: Alarm: Hard limit -Y. So decided something must be wrong with framing so I just tried to cut a small 10mm by 10mm square. And as you guessed it said this: Alarm: Hard limit -X. I have searched and searched but I have not found an answer to my problem. If anyone knows the answer to this it would help a lot, thanks.
You did a controller update and the results are that it’s generating the error message…
Does it actually move or immediately give the error?
Usually the hard limit means the limit switch has been activated…
Can you check if that’s the case?
On some machines, the limit and home switches need not be the same… Don’t know about the Smoothie…
I think @berainlb knows these boards… maybe he can come bail us out.
What specific board did you get for the swap?
Did the machine work prior to the swap? How did the swap go? anything of note there?
Can you provide the following:
- full screenshot of LightBurn with your design loaded and ready to run
- screenshot of Edit->Device Settings
- upload your config.txt file here
I am having a similar problem. Any help is appreciated.
ALARM: Hard limit -X
On or near line 6006:
// NOTICE limits are disabled until all have been cleared
On or near line 6006:
Stream completed in 1:33
Starting stream
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Did anyone find a fix? I have the same issue
I got this: Desktop 40W Laser Engraver LightBurn Compatible Motherboard - OMTech – OMTech Laser. I immediately swapped the board without using the previous.
It’s been a while since your original post. Is the machine now working for you?
If not, can you answer the other questions from my previous post?
It is not working. I will try to get the information.
Try switching “Start From” mode in Laser window to “Absolute Coords”. Then home the laser and make sure you never attempt to move the laser head by hand. Then retest.
What is the outcome?
That worked! Thanks for your help!
Why doesn’t this work with user origin?
I think I do something very similar with my grbl dpssl… The only time I use absolute coordinates is making a template…
Just curious on what I’m missing…
There’s nothing inherently preventing it from working. However, user origin is easy to get wrong which can lead to crash or hard limit scenarios. Specifically, setting of the actual user origin itself at a location that doesn’t allow for enough clearance for the shape being burned.
Also, it may not have been specific to the user origin. If there was manual movement of the head after homing there was potentially lost motion unaccounted for by the controller. Either or both of these scenarios could cause the reported problem.
Thus, going to absolute coords and avoiding manual head manipulation removes both as potential issues and allows a verification of base function for the machine.
Does Lightburn send absolute moves to the controller and no relative moves… or just starts out with absolute moves…
Sorry, haven’t even though about how this addressing works when the grbl is generated…
In Absolute Coords both absolute and relative moves can be used. It’s not apparent to me what determines which use in each case. From what I recall the initial start position is always specified in Absolute Coords.
I haven’t looked at user origin as readily but I believe it’s similar to Absolute Coords. I’d imagine that initial start position would be specified in absolute coords.
Current position from what I recall makes no reference to absolute coords.
By the way, this is specific to gcode. Evidence suggests that DSP machines may work a bit differently, particularly with current position but I haven’t explored this thoroughly.
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