How do I manually adjust for bed concave in RepRap Firmware?

Hey, I'm going to be without a proper Z-probe for a couple of weeks, and I noticed that when manually leveling my bed, the nozzle height at the towers is about 1.40mm above where it would be at the Z0X0Y0 coordinate, producing a sort of "shallow bowl", if, the deformation was mapped.

Before you say it, yes, my bed is absolutely flat. It is glass, and I measured it myself to make sure. My effector rods are on Magball suspension, with less than .01mm measurement difference between all 6. My physical bases are covered. the height adjustment screw on each carriage is adjusted so that they're somewhat even (within .2mm) when paper testing at the 3 points around the towers.

Is there a good way of ironing this out? I know how to do it in Marlin, but I'm on RRF now, with 32-bit hardware, and this is a whole different ballgame. Is it a matter of adjusting Delta and Printable Radii, like it is in Marlin, or is this calculated differently?

Edited 2 time(s). Last edit at 12/19/2017 02:17AM by Lobotomy.

You could use stepper stall detection to home the printer ( Duet boards with 1.20beta only ). That leaves three unused switches for any z-probe you like. I had good results with the "allen key" z-probe. Although you'd need a printer to make the bracket....

Using latest stable (1.19.2) or release candidate firmware and DWC, you can set Z probe type 0 in the M558 command, then run auto calibration as normal. DWC will prompt you to lower the nozzle to touch the bed each time the firmware needs to probe.

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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].

Unfortunately, as I have a RADDS, I do not have access to the Web Controls at this time, and I think the 1.20 RC may not be compatible yet. However, I do plan on buying a couple of wifi modules, and playing around with them. As PanelDue uses the four pins I would need for PanelDue, is there a means of using both the Wifi Module and PanelDue at once? Is there a second set of tx and rx pins I can use for one or the other?

Is there any way to get the prompts over PanelDue or Pronterface? I pressed the bed leveling button on PanelDue, but nothing came up in the console. I'll mess with Pronterface to see what I can get.

I wonder how much of a stretch having an ethernet controller would be, if wifi is an available option? I'd much prefer that.

Edited 2 time(s). Last edit at 12/19/2017 07:19PM by Lobotomy.

Before you can use bed levelling, you have to generate a valid bed.g file. ( AFAIK, the implemented bed.g file has all lines commented out...)
You can edit the existing one, but easier is to use the configurator on configurator.reprapfirmware.org
The configurator is a bit annoying, if you are not used to work with it. Especially when you only want to generate a new bed.g file.
(I haven't found out what a "json" profile is yet...)

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Lobotomy
Unfortunately, as I have a RADDS, I do not have access to the Web Controls at this time, and I think the 1.20 RC may not be compatible yet. However, I do plan on buying a couple of wifi modules, and playing around with them. As PanelDue uses the four pins I would need for PanelDue, is there a means of using both the Wifi Module and PanelDue at once? Is there a second set of tx and rx pins I can use for one or the other?

I didn't do the initial RADDS port, however I see from the Pins_RADDS.h file that the standard build supports only USB plus one serial port.

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Lobotomy
Is there any way to get the prompts over PanelDue or Pronterface? I pressed the bed leveling button on PanelDue, but nothing came up in the console. I'll mess with Pronterface to see what I can get.

You can use Pronterface if you send the G32 command from it. The next release of PanelDue firmware will support it there too.

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Lobotomy
I wonder how much of a stretch having an ethernet controller would be, if wifi is an available option? I'd much prefer that.

The Duet Ethernet has been available since about March 2017.

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o_lampe
The configurator is a bit annoying, if you are not used to work with it. Especially when you only want to generate a new bed.g file.
(I haven't found out what a "json" profile is yet...

You can also use my original bed.g generator at [escher3d.com]. A JSON profile is a file that saves the configuration on your PC, so that if you subsequently want to change it you can import the one you saved and start from there.

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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 David! I knew there was a better way to generate bed.g only. But I thought it was overwritten by the configurator. Maybe it is worth a hint on the startpage of the configurator? Or one could add another choice:" generate bed.g only"

Alright, my Z-probe is recognized, but it doesn't want to stop when I try to probe the bed. Am I missing something? What does the T parameter do in G31?

Edited 3 time(s). Last edit at 12/21/2017 08:58PM by Lobotomy.

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Lobotomy
Alright, my Z-probe is recognized, but it doesn't want to stop when I try to probe the bed. Am I missing something? What does the T parameter do in G31?

In what way is the Z probe recognised? Does the Z probe value displayed by DWC or PanelDue go from a low to a high value when you trigger the Z probe?

RRF supports multiple Z probes. You can switch between them using the P parameter of the M558 command. The T parameter is used to set the G31 parameters for a Z probe type other than the one that is currently selected.

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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].

It's recognized in M119's output, and by some weird happenstance, it will now stop if I press the switch after it moves downward upon a G30 command. It didn't do that before.

Which gcode does the orange autoleveling button use in PanelDue? Or is it a macro?

Edited 1 time(s). Last edit at 12/22/2017 11:53PM by Lobotomy.

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Lobotomy
Which gcode does the orange autoleveling button use in PanelDue? Or is it a macro?

It sends G32, which runs bed.g.

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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].

Alright, this is my bed.g. Maybe I am missing something?

; bed.g
; called to perform automatic delta calibration via G32
;
; generated by RepRapFirmware Configuration Tool on Sun Dec 10 2017 02:25:28 GMT-0500 (Eastern Standard Time)

; Clear any bed transform
M561

; Home all towers
G28

; Probe the bed at 3 peripheral and 0 halfway points, and perform 3-factor auto compensation
; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
G30 P0 X0 Y0 H0 Z-99999
G30 P1 X0 Y90 H0 Z-99999
G30 P2 X-78 Y-45 H0 Z-99999
G30 P3 X78 Y-45 H0 Z-99999 S3
; Use S-1 for measurements only, without calculations. Use S4 for endstop heights and Z-height only. Use S6 for full 6 factors
; If your Z probe has significantly different trigger heights depending on XY position, adjust the H parameters in the G30 commands accordingly. The value of each H parameter should be (trigger height at that XY position) - (trigger height at centre of bed)

Also, if my Z-probe is 20.94mm underneath the nozzle, I'd set that with G31 Z-20.94, right? Or would it be positive? Only asking because stranger things have happened.

Edited 1 time(s). Last edit at 12/23/2017 11:22PM by Lobotomy.

You have selected 3-factor calibration (S3 on the final G30 command), which adjusts the endstop corrections and homed height only. You need to adjust the delta radius too, so you need S4. Most people use 6 or 8 factor calibration, but of course you need more probe points for that.

If the Z probe triggers when the nozzle is 20mm above the bed, then the Z parameter in the G31 command should be +20mm.

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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].

I was only probing those points, because those were known to be good starting points. I'll make a more elaborate bed.g later, and now that it works, I can do just that. Thanks for all the help, hopefully I can start printing very soon!