I’m not entirely sure where this problem lies but it is an interesting one.
Lightobject Z Table
Omtech motherboard upgrade for k40
This board is a smoothieware board that gives full lightburn support, a z and rotary axis, and several other things you can connect up.
When I first turn on the laser and start lightburn it auto homes the x/y axis just fine.
Then When I click to move the z table, not much happens. The z table stepper motor just kinda vibrates a tiny little bit.
Now the interesting part.
If I click Go, and then click on the Home button then the Z table controls start working. I’ve tried this many different times, and no matter what the only way to get the z table functional is to start running those commands.
One thing I did notice in the log is that upon start up it says :
ok
G0
Smoothie
ok
ok
Homing
$X
G28.2 XY
ok
When you normally do a Home button then the following happens:
$X
G28.2 XY
ok
However, after running the home command after running a Go command then this is what the log says:
$X
G28.2 XY
[Caution: Unlocked]
ok
ok
Notice the [Caution:Unlocked] part. Whatever it is that causes that is what then allows the z-table to function.
Any ideas on if there is some sort of configuration (either of smoothieware or lightburn) to force this to work without doing that Go/Home dance?
I think so. I slugged through this a few months back.
The first suggestion is confirming that you have selected Absolute Coords as the Start From option in the Laser window in LightBurn. The other ‘Start From’ selections add a little bit of complexity.
The config file that smoothie uses will let you do all kinds of things.
On a K40 the switches used for homing are most often located rear left in the machine. The config file may have set up the laser with 0,0 being the Front Left corner. This is the most common setup.
With LightBurn, running and connected to your K40, open the Move window and set the speed to 300 mm/s and jog distance to 30mm. Test the four compass points around the Home Icon on the left and confirm that the head of the engraver moves as you’d expect.
If a pair of Jog arrows works backwards, (a typical example would be, Back to Front & Front to Back) we move the Origin to its opposite corner from Back - to Front, or vice versa in Device Settings.
If you’re interested and you have the Config file handy, make a copy of it somewhere convenient, change the filename extension to .txt then upload it here.
I’d like to see how Omtech set up their Config file.
I double checked and on the Laser window, Start From is set to Absolute Coords. The laser does move left / right and front/ back exactly as I expect with the Jog arrows. I can send a job to it and it does come out exactly as I expect.
I was starting to wonder if maybe flashing a new version of smoothieware might be a way to resolve. The version it is currently running is:
version
Build version: edge-54d22942, Build date: Jun 5 2019 14:09:26, MCU: LPC1769, System Clock: 120MHz
CNC Build NOMSD Build
4 axis
ok
Well, I tried grabbing the latest smoothieware code, built that, and flashed the board. The only real change is that the message was slightly different.
I’m trying to look through that code but I’m wondering if it thinks there is a limit switch attached to the z-table. I don’t have one configured for it. If it thinks the limit switch exists, and is active, then it would stop the stepper from spinning until it gets that limit failed message. At which point it would then just allow everything to move around.
I’m going to wire up a limit switch and attach it to the board and see what happens.
