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Strange moves when auto calibrating Mini Kossel delta

Posted by Captain_sq 
Strange moves when auto calibrating Mini Kossel delta
November 17, 2017 03:03PM
Hi,
Got myself a custom built Mini Kossel delta with a Duet 0.6 as controller. I use dc42's 1.19 fork of the firmware with the same DuetWebControl. I managed to calibrate it fairly with the help of Eschers wizard but still have a deviation of about 0.83. It moves correctly in all directions using G0 and G1 commands and homes. It's when I start the auto calibration feature strange things start to happen. The bed.g file has been adjusted with the Eschers bed file generator for 10 points and 6 factors. When I start the auto calibration the printer goes wild. For every G30 command it makes weird moves prior to, and after the actual probing of the point. These "rougue" moves are outside the printable radius. The first move crashes the cooling fans into the Z-belt making the magnetic right Z-rod come lose. after that, it returns to the center and starts probing normally. When done, it makes another move out in no-mans-land to the left and starts to what appears to be a sort-of probe move but it stops halfway down and then returns to the middle and halts. I have attached a link to a film clip that shows the procedure of a single probe sequence using this command: G30 P0 X0 Y77.9 H0 Z-99999 and the subsequent printers response. What is the cause of this?

Link: Single probing /w G30
Re: Strange moves when auto calibrating Mini Kossel delta
November 17, 2017 04:52PM
See [duet3d.com].



Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Strange moves when auto calibrating Mini Kossel delta
November 17, 2017 06:09PM
Hi dc42,
Thanks very much for the fast response. That explains it. One further question comes to mind; it seems like the deploy and retract .g files are invoked before and after each G30 command, even inside the bed.g file which will result in the deployment and release of the probe (in case the probe is of the retractable kind) for each probe point. Is this intentional?

Best regards /Thom
Re: Strange moves when auto calibrating Mini Kossel delta
November 17, 2017 11:45PM
I think his point was to remove the deploy and retract probe folders.
Re: Strange moves when auto calibrating Mini Kossel delta
November 18, 2017 02:25AM
Quote
number40fan
I think his point was to remove the deploy and retract probe folders.

Yes, I understand smiling smiley. My second question is about why it makes sense to do the deploy/retract sequence (IF you have a retractable probe) at each and every single probe point (G30) instead of once per invoking of the the bed.g macro. To me, it makes more sense to control this behavior in the bed.g file itself using the traditional way with the "M98 Pdeployprobe.g" and "M98 Pretractprobe.g" commands. For example, if you have a BLtouch probe or a simple microswitch, those kind of sensors will not require a "reset" between probing of each point which will be performed as those macros are called automatically at each G30 in the 1.19 firmware as described in the upgrade notes for this version. Please correct me if I'm wrong.

Best regards /Thom
Re: Strange moves when auto calibrating Mini Kossel delta
November 18, 2017 03:18AM
If you use M401 to deploy the probe at the start of bed.g and M402 to retract it at the end, then it won't deploy and retract on each G30 command.



Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Strange moves when auto calibrating Mini Kossel delta
November 18, 2017 08:29AM
Quote
dc42
If you use M401 to deploy the probe at the start of bed.g and M402 to retract it at the end, then it won't deploy and retract on each G30 command.

Thanks, problem solved.

/Thom
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