Dual Z motor bed leveling
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I'm building yet another machine. This one uses the mechanics of a Prusa i3 in an aluminum extrusion frame.
When I run G32, I get the following error immediately after the probes to level the dual motors:
"G32
Error: Probe points P0 to P1 must be in clockwise order starting near X=0 Y=0"Here is my bed.g
; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool on Thu Jun 29 2017 21:34:03 GMT-0700 (MST)G28
;Testing
M401 ; deploy Z probe
G30 P0 X20 Y80 Z-99999 ; probe near a leadscrew
G30 P1 X200 Y80 Z-99999 S2 ; probe near a leadscrew
M402 ; retract probe
;Testing; Clear any bed transform
M561
;# Deployprobe.g
M280 P3 S10 I1;Run Mesh Grid Compensation
G29;#Retractprobe.g
M280 P3 S90 I1What am I doing wrong?
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That message indicates that it isn't doing leadscrew bed levelling, it's executing the old code to to 3, 4 or 5-point bed compensation instead.
What M584 and M671 commands do you have in config.g?
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M584 X0 Y1 Z2:3 E4 P3 ; Dual Z Homing
M671 X-67:328 S0.5 ; leadscrews offset for levelingIn case it matters, I'm running v1.20 of the firmware.
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You need Y coordinates in the M671 command too. If you have only 2 leadscrews, use the midpoint of the Y axis, e.g. Y100:100.
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OK. Thanks.
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It works now but it tilted the bed by 2mm to one side. With a mostly level bed, it kept giving me errors about exceeding calculations. I kept having to increase the S value finally settling on S3.0 for it to not give an error. Then, the bed leveled itself but 2mm off to one side.
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how are your Z motors connected?
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Check that your Z probe has the same trigger height at each of the two probe points. See https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height for how to measure it.
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I relevelled the bed manually by turning the leadscrews with the machine off and checked the Z probe trigger height and it was 2.4mm at all locations testes. I then ran a G32 and got this error.
"G32
Error: Some computed corrections exceed configured limit of 0.50mm: -2.039 -1.683"I am probing at X20 Y100 and X190 Y100
The results of the mesh leveling were:
Number of probe points: 25
Probe area: 256.0 cm²
Maximum deviations: -2.125 / -1.718 mm
Mean error: -1.961 mmRMS error: 0.121 mm
The heightmap is almost flat
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how are your Z motors connected?
Right motor in Drive 2 and the left in Drive 3. Jumpers in the second Z motor port.
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The main problem is that you have a large Z offset, both in the height map and in the bed leveling result. Looks like your Z=0 position after homing Z is off.
