Auto leveling sometimes reversed!

Hi ,

I have a Tinyg setup with a Chinese 3040 and I have a strange problem with the auto leveling widget.

Mostly it works fine but occasionally , after running a successful test probe, is reverses the direction of the Z axis, probing upwards (away from the work) and if left would hit the Max Z limit switch.

The only way I can clear the issue is to shut down my browser, restart the Tinyg and the Json server.

There are no errors I can see in the console.

My setup is Windows 10, with the Tingy directly connected via USB.

Any advice would be appreciated.

Thanks in advance,


My method of working for pcb milling:

Start CNC (tinyg) > Start Json Server > Start ChiliPepper

Drag and drop eagle file on the workspace > Change Eagle widget import settings as required and send gcode to the workspace

Load Auto-level widget > Run test probe > Set Machine Zero > Set G54 Zero > Run Auto-level


Link to and Tingyg config txt file:!Ahcdu5kP4Diz4UUSo0vb1KBZBkkC?e=a7M0fl

Only time I’ve ever seen that is 1st time after writing a configuration in TinyG. There was/is a TinyG bug that it would have the Z direction reversed internally until it rebooted after a config. So, I never write a config without rebooting afterwards now.

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Ok thanks John.

I think there maybe a bigger issue, as my Tinyg now seems to be hanging on M6 commands.

When paused for a tool change, after around an hour or so milling, it now becomes unresponsive and needs to be power cycled to get it back up and running. It’s strange because it’s been OK and nothing has changed.

I’m a bit lost really… I’m starting to wonder if there’s s a better / more reliable board for my CNC and Chilipeppr for newbies like me!

I run the maxiGerbil board from and love it. It is a 5 axis capable board running 32bit GRBL-STM firmware. Has all the bells and whistles you could ever want.

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M6 should not hang your TinyG as it does nothing to it. M6 just tells ChiliPeppr to stop sending Gcode. My guess would be your USB cable, but that could be a long shot. I’ve just recalled hearing many folks say a bad USB cable will cause some whackiness.

Paul… I had a similar problem using Super Touch, and it seemed random, to be sure. But it turned out to be related to what coordinate system was the focus (like G55, for instance), and where the zero position for that coordinate set was relative to where the spindle is at currently. I have never used auto level, so you will have to research this yourself. And to confirm what John Lauer said above, after I save a new config, I do a hard power down, then back on. Otherwise I have gotten random results. …Jack

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