Inventables Community Forum

Its all gone pear shaped ! GRBL 1.1g

Can anyone give a bit of advise ? Long story , been trying to get j-tech laser working with lightburn & x carve … short story gave up on laser !!! cnc is now its not working ! grbl 1.1g loaded, ugs 2.0 nightly & vectric aspire ! I did change the settings in lightburn for the laser to work , but I thought they were changed back for the cnc ! can anyone see a fault in the grbls here ? It might be something Ive overlooked , but I wish I had a note of what they all were before I started mucking about with this blooming laser ! Now its doing funny stuff when trying to do a carve eg locking up ! starts cutting then stops ! keeps saying grbls busy ,trying to go past hard limits etc .HELP ! Im sure somethings not right here !
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Nothing is TOO out of the ordinary I suppose except for maybe $10.
See: grbl/settings.md at master · gnea/grbl · GitHub

What is the problem you are having?

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Brandon Parker

Have you always run with hard limits?
I’d set $21=0 (no hard limits)

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Unless all of the required limit switches are installed… :wink:

I completely missed that one…

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Brandon Parker

It seems to have lost its bearings Brandon ! eg . looks like its trying to go past the limit switches & obviously just cuts out , then the next time it (same file) it only got a few mm then cut out …I will have another wee look at grbls today .Im sure its something Ive changed in lightburn Its been a total nightmare trying to get the laser to work & in my frustration I have probably changed something there ! Shame Ive been using the cnc for well over a year now with no complications …well after I got it set up for Aspire , ugs etc , its a wee bit frustrating not having internet in the workshop & makes things a bit more difficult to download etc as its just through teathering to phone ,with bad signal :crossed_fingers: its an easy fix

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Ah cheers Neil …I have just been using the limit switches that came with the x-carve & homing after every carve ! eg . just the 3 of them !!! Its worked well for me up till now … OH I ran into a conversation ages ago , from people far more tech savvy than me , about Hard limits , soft limits … head was spinning & had to turn off :grimacing: some saying " the limit switches are not hard limit switches & vice versa :persevere: it was an in depth conversation & I came away knowing a lot less than when I started reading :laughing: … I dont think it ever came to a conclusion & morphed into the best most efficient way of starting , folks a lot more advanced than me !!! trying to cut down on a few seconds carving time is not what Im after , just would like it to work as it has been :+1: ! but basicly its just that …limit switches & homing is what I have been using !

If it is going in the wrong direction, look at $3. Otherwise, I might run back through the setup process in Easel.

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Brandon Parker

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Does the carve look correct in the preview?
Can you share a photo of the carve preview in either Aspire or the gcode sender (I’d presume Easel)

There is an option to “offset” the datum in the job settings within Aspire and this being checked is a rather common setting mistake for first time users. Additionally, the assigned Datum itself could also be the issue if you are not setting 0,0 per the selected location for the Datum…
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Also, what direction is it driving past the limits? too far Left, Right, Forward, Back?
Depending on where it’s going (forward or left) then your $3 might not be correct.
You can also verify $3 is wrong by testing if manual commands drive the correct directions, left goes left, firward goes forward, etc… aldo Reference Brandon’s first post for a link to the chart to use to fix this issue.

Here are the Defaults for X-Carve grbl settings:

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Hard limits on hobby machines, especially those with routers or big spindles, are prone to EMI. This will cause false triggers of switches and stop the machine.
One of the most frustrating issues to deal with.

If you know what you are doing, you can set up all of the required limit switches and hard limits with no issues. It makes no difference whether the machine is a hobby machine or not when dealing with possible EMI issues; even professional milling machines have to design around possible EMI issues.

Just saying…

I think we can focus on the OP’s issue with the “pear-shaped” issue instead of debating whether one can/should implement hard limits on a hobby-grade machine.

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Brandon Parker

Cheers Seth ! I will have another look next week :+1: I have been using it a lot before the laser carry on ! has been working great before that , Ive not got it here just now but thinking about it , It was showing up in ugs with the spindle in the centre of the small grid …Its a 1m x 1m x-carve & always starting bott left ! On jogging with no file loaded , the pointer / spindle icon would go off screen to the right & top ! , when loading a carving file from Aspire it starts bott left on screen ,but goes past the carving on the Y axis & tripping the X axis limit switch , oddly enough the little part it did carve looks in the right place . looks like table dimensions or something has got mucked up ! Im sure the offset & starting points in aspire are as per usual & bott left … but I will check that to ! Thanks for taking the time to help here !!! :+1:

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Cheers BrandonR :+1: yup if I can just get it back to carving normally just now that would be great !!! I know how easy it is to take forgranted the smaller issues when trying to help / teach someone . I had to stop myself with apprentice joiners/carpenters :grimacing: & although I have got a good few carvings under my belt I am well aware that I am anything but a machinist ! unless it has big cogs , pullys & can be fixed with hand tools :laughing: Cheers for taking the time to help :+1: Ill have another go next week :crossed_fingers:

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Definitely keep us updated with the progress, and let us know if you need further assistance.

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Brandon Parker

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Sounds like false triggers on the limit switches to me. On topic. Trying to help. Not starting a debate. Trying to solve the OPs issues as described. I would disable hard limits as a start to see if the problems are related.

???

Not sure why my last post was flagged.

@berserker Try turning off hard limits. Set $21 = 0. False triggers on those limit switch pins can cause the exact issues you’re seeing.

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:man_shrugging: Not sure Neil !

Did you try disabling hard limits?

To turn off hard limits via Easel, do the following:

  1. Go to Machine>General Settings>Machine Inspector
  2. Type in “$21=0” into the Console TextBox and press Enter

  1. Then type in “$$” and press Enter to get the GRBL Settings returned from the controller.

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Brandon Parker

Hi again Neil / [SethCNC] /( [BrandonR_Parker] managed up to the workshop just for a wee bit today , It looks like the table size has changed , router moving the correct directions but showing as negative numbers eg …Apologies on photo quality :grimacing:
Pic showing spindle when homed !


& after moving one click in the correct directions …

If I remember correctly on setting up the x-carve / ugs I had to reverse the z axis !
Everything is moving in the correct direction when jogging . there are a few funny looking $ codes , but I cant find an actual copy of what grbls 1.1g should look like ( it is a 1mx1m table sized x-carve ! here is what Ive got just now
Im wondering if I need to delete ugs completely & totally reinstall everything , If I do would I need to go right back to the start eg through easel etc ? It will be a bit of a pain due to lack of internet but if thats what it needs Ill just need to , I could probably just rewrite all the grbls manually ? if I could get a note of what they are supposed to be !
Would I be right in saying while jogging from homing/ zero …numbers should be positive in X & Y and negative in Z ?
Thanks again for the help !

If the router is moving correctly, you’re good. The negative numbers are your MACHINE position, and you shouldn’t need to worry about those. That just provides an absolute reference for your WORK position which are represented by the larger numbers in the digital readout.

Grbl defines, by default, the MACHINE zero as back right with the Z up. Everything in your usable space is in negative MACHINE space. Again, the WORK zero is what matters.