Hello fellow makers! I finished a custom plasma table that runs on the Uno and GRBL 1.1. I use the OpenBuilds Control to execute commands. Everything homes (bottom left corner, a coreXY setup) and moves correctly, however, the probing cycle initiated from the dedicated GUI gives me this alarm: ALARM: 2 - G-code motion target exceeds machine travel. Which is confusing, because if I send the following gcode through the serial console (G38.2 Z50 F200 it works flawlessly. The plasma tool's tip moves down, touches the metal plate and the downward Z axis movement stops immediately. But here's the good part: When I tried to launch an actual gcode generated with OpenBuilds CAM, after these command lines (G38.2 Z50 F200;G10 L20 Z0; Set Z Zero) finish, the plasma tip plunges down to the metal I wanted to cut - where in fact it should've moved up to the specified arc starting distance. I tried to set negative values in the CAM but then it doesn't generate the gcode. So what am I missing here? I tried to play with #define HOMING_FORCE_SET_ORIGIN and all but couldn't figure it out. Thank you in advance.
Please don't enable that - it just creates more problems for you. CONTROL is designed to work properly with default Grbl configs Remembered to Home and set your Max Travel values correctly to properly define the movable area? Grbl Wiki explains Soft Limits quite well, but just remember Machine Coordinates are seperate from Work Coordinates, and all you really need to is to remember to Home to properly establish the Machine Coordinate System With a touchoff / floating Z make sure to set Z-max travel appropriately to allow enough overshoot Post screenshot of the values you entered, and the Probe Macro you defined in SETTINGS
Hi Peter! Thanks for the quick reply. To remark your first suggestion: Did a fresh USB-plug-in and Home in CONTROL and the positions I get back in are some strange numbers. For clarification, soft limits are enabled with X=550; X=565 and Z=50 mm each. So I don't even know why I get these numbers. X and Y are at least close but Z is completely wrong. If I click on the Z probe button right after it finished homing, it starts, but stops quickly with the error: 15 message stating that the jog target exceeds machine travel. About the CAM settings, here you can see them: The probe code was the same as I mentioned earlier: G38.2 Z50 F200; Probe G10 L20 Z0; Set Z Zero Did these inputs help you clarify my problem?
Images are not showing up. Use the UPLOAD A FILE button below the field where you enter the message to upload, then use the Insert buttons next to the images once uploaded
If you want to use touchoff you also need to define your Probe Macro in SETTINGS. And enable Touchoff in the toolpath The DRO values just indicate you haven't SETZERO yet. See Frequently Asked Questions · gnea/grbl Wiki
That wiki page is full of useful information. I'll take my time this weekend to re-educate myself because indeed I come from the additive manufacturing world where coordinate systems are much simpler. If I may ask, please don't close this thread, I'll come back in a few days with hopefully a solution worth sharing - or another question to narrow down the issue with my setup. Thank you for your great help so far.
We almost never close threads (unless they become unruly hehe) Machine coordinates aren't too hard to understand but yes, coming from 3D printing where they totally ignore it, is a learning curve. Still waiting on you to screenshot me your macro - OpenBuildsCAM > Settings tab > Settings button > Plasma: Touch Off Sequence For example mine: (yours will be different - experiment until you have a macro that perfectly zeros) and also make sure you are telling CAM if you want to use the macro: along with proper CUT HEIGHT, PIERCE height etc
Hi! I'm back with more confusion.. I loaded a fresh gcode generated in the OB CAM and after homing, I launched it. The console immediately tells these error messages in quick succession: error: 9 - G-code locked out during alarm or jog state [ G0 Z2.5 ]<hr>This error may just be a symptom of an earlier event:<br> ALARM: 2 - G-code motion target exceeds machine travel. I attached my macro and my GRBL config file. I have a notion that I misconfigured something in the general grbl settings that causes this super annoying issue. Just to be clear: my machine home position is the bottom left corner, all endstops are pluuged into their MIN input. After homing, if I jog manually to the positive direction, X moves to the right, Y moves further away from the origo and Z moves UP.
Means you either forgot to Home, or you have Max Travel / soft limits setup incorrectly, or what you were attempting to do really would have violated the working envelope inside the Soft Limits. See the Grbl Wiki for details
I went through my settings and didn't notice any wrong lines of code. Could you please take a quick look at my settings (attached previously) and my machne's behaviour? Perhaps I missed something.
As mentioned And Code: $132=50.000 ; Z-axis maximum travel, millimeters Does the machine really only have 50mm of Z travel? If so, you are trying to probe downward Z50 as well in your macro... Which is of course not possible as there is no space left. So either max travel is set too low, or your macro is probing too far.
Yes, it really only has 50 mm of travel. Macro aside, after homing the machine and hitting a Z probe option, the Z axis starts to move down towards the plate but then suddenly stops and gives me this error message: error: 15 - Jog target exceeds machine travel. Command ignored. [ $J=G91G21Z5F1000 ] Why does this happen?
Yes... but see: (from your screenshot on Thu) You want to G38.2 Z-50, Max travel = 50.... Where do you think Grbl should move to if the limit is 50, but you want to move by 50mm. 50-50=0 - and thus the cause of your error. Thus: I'd suggest you either Disable Soft Limits until you understand them better, or set Max Travel higher
