Bed Compensation Error

I have a problem with Auto bed compensation, It does not measure it correctly for some reason.

for example:
Bed equation fits points [50.0, 25.0, -0.028] [50.0, 195.0, -0.112] [200.0, 195.0, 0.763] [200.0, 25.0, 0.781] [120.0, 104.0, -0.131]

These two [200.0, 195.0, 0.763] [200.0, 25.0, 0.781] are 0.2-0.3mm higher then they should be making a slope. So making it imposible to print becouse the fillament will not stick to the bed at the single bed leveling screw.
I cant manualy level the bed becouse i have a problem with Rod Twist i am still trying to remove.

What could be cousing wrong readings?

I am using DC42's sensor and do have black paper under the glass with Kapton tape.

There is a parameter for an offset, but I do not know exactly which it was.
[reprap.org]

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Hi Darathy,

If the IR probe triggers at different heights depending on where on the bed it probes, it can be compensated by using the H parameter in the G30 command. See reprap.org

Cheers,
Bart

So i need a bed.g file then add

G30 P2 X200 Y195 Z-99999 H-0.2
G30 P3 X200 Y25 Z-99999 H-0.2

Becouse it slopes down right?

I cant just add here in my config file?:
M557 P2 X200 Y195 H-0.2 ; ...for bed...
M557 P3 X200 Y25 H-0.2 ; ...levelling

Edited 1 time(s). Last edit at 12/29/2015 08:29AM by Darathy.

Hi Darathy,

The G30 bit sounds about right.

From what I can see in reprap.org, the M557 command does not take the H parameter so it looks like you have to use G30. Why do you not want to use bed.g?

Bart

You cannot use the H parameter on M557 but you can use it on the G30 commands in bed.g.

Do you have the recommended black paper or paint under the glass bed? Otherwise, blemishes and scratches on the aluminium can cause the trigger height to vary with position. Also check that you are not probing with the sensor head too close to the edge of the bed.

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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].

Quote
dc42
You cannot use the H parameter on M557 but you can use it on the G30 commands in bed.g.

Do you have the recommended black paper or paint under the glass bed? Otherwise, blemishes and scratches on the aluminium can cause the trigger height to vary with position. Also check that you are not probing with the sensor head too close to the edge of the bed.

Yes i do have printed Black paper under the glass, i will try with bed.g file with H parameter and see if it improves

do i need to disable the probe points in Config file if i have bed.g file?

You shouldn't need to. G30 will probe at the coordinates specified in its command line. If you don't specify coordinates (but include a P value), it probes at the current position.

Bart

If there is a bed.g file then the probe points set by M557 are ignored.

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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].

[deleted]
(answered my own question)

Edited 1 time(s). Last edit at 12/29/2015 11:40PM by bartdietrich.

thanks for the help evryone ,its working fine now