suggested addition to the dc42 firmware

My normal zprobe pattern is setup for a 300mm bed, but for small prints I realized that I don't need to probe the entire bed and a small pattern should give me a tighter fit (assuming the smaller zone implies less average deviation).
How about a way to use one (or more) alternate bed patterns from the interface?

On second though that might have a problem. If the diagonal dimension is calculated from the probing, a small pattern on a large frame might increase the error there.

You can do this already. Just set up alternative versions of the bed.g file, name them suitably and put them in the /macros folder on the SD card. If you use 6-factor calibration then the diagonal rod length is not calibrated.

Edited 1 time(s). Last edit at 10/27/2015 04:05AM by dc42.

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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].

Gone through that yesterday. Tried to alter the probing points for a print radius of 140mm ( instead of 85 from the mini Kossel )
Problem was, that the offset of my probe was ignored and I probed outside the bed a few times.

I don't know, why I define the probe-offsets in config.g and ignore them in bed.g:

M561               ; clear any bed transform, otherwise homing may be at the wrong height
G31 X0 Y0 	; don't want any probe offset for this

Should I recalculate the probe points manually or reduce them to fit the bed?
-Olaf

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o_lampe
Should I recalculate the probe points manually or reduce them to fit the bed?
-Olaf

Take the ones you calculated already, and where they cause the probe to be outside the bed or too near the edge, move them in a little. The probe points don't all have to be at the same radius.

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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].

Thanks ( again ) David,

wouldn't it be great to have a "generic" bed.g which the firmware scales up or down related to the print radius or a selectable scale-factor?
-Olaf

oops, used to relying on the Autocalibrate button, thanks.
Also, my mistake, I already use 6 factor. I meant the arm radius. Normally one manually puts that in but your routine calculates it out. Bed curvature will not be detected as precisely if the probe region has a small diameter compared to the frame size, which means the XY print dimensions will have a larger error. Am I wrong?

Quote
shadowphile
oops, used to relying on the Autocalibrate button, thanks.
Also, my mistake, I already use 6 factor. I meant the arm radius. Normally one manually puts that in but your routine calculates it out. Bed curvature will not be detected as precisely if the probe region has a small diameter compared to the frame size, which means the XY print dimensions will have a larger error. Am I wrong?

None of the factors will be calibrated as accurately using a smaller probing area, except for the homed height. But they don't need to be as accurate with a smaller print area. However, if you have already calibrated using the full bed size and saved the values in config.g, then prior to doing a small print, instead of running auto cal again you might just want to set the Z height. You can do that by running e.g. G1 X0 Y0 Z3 F6000 followed by G30.

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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].