z-leveling again...

HenryLoenwind

configuration.h: https://gist.github.com/HenryLoenwind/442ca59bb0838fb8e694f83f11a1b698

eeprom: https://gist.github.com/HenryLoenwind/f31d0f1e795cb8df47a1b0ae049ecd5f

version: git 185b05c08090a378415e03bef5f0d9f4a251d116

Short: G32 S2; G33; G28 -> probe hoovers ~2.5mm over the bed

I had some problems with z-leveling in 0.92, so I upgraded to the current dev level. Didn't really help. ;/

I have a cartesian printer, the z-probe is one of those pressure pads you stick onto the nozzle. Probing works quite well, but I cannot get it to actually get near the bed afterwards.

As the bed is big enough to need distortion correction anyway, I also tried disabling autolevel (M320 S2) and only use distortion correction. Didn't help.

G33

21:29:12.644: Z correction disabled

21:29:12.646: Reference Z for measurement:10.500

21:29:51.786: Z-probe:8.206 X:10.00 Y:239.98

21:30:06.545: Z-probe:8.443 X:48.33 Y:239.98

21:30:21.575: Z-probe:8.674 X:86.66 Y:239.98

21:30:36.867: Z-probe:8.896 X:124.99 Y:239.98

21:30:52.472: Z-probe:9.160 X:163.32 Y:239.98

21:31:08.486: Z-probe:9.526 X:201.65 Y:239.98

21:31:25.070: Z-probe:9.999 X:239.98 Y:239.98

21:31:43.126: Z-probe:7.920 X:10.00 Y:201.65

21:31:57.583: Z-probe:8.180 X:48.33 Y:201.65

21:32:12.355: Z-probe:8.456 X:86.66 Y:201.65

21:32:27.436: Z-probe:8.714 X:124.99 Y:201.65

21:32:42.886: Z-probe:9.025 X:163.32 Y:201.65

21:32:58.799: Z-probe:9.435 X:201.65 Y:201.65

21:33:15.253: Z-probe:9.889 X:239.98 Y:201.65

21:33:33.225: Z-probe:7.845 X:10.00 Y:163.32

21:33:47.594: Z-probe:8.105 X:48.33 Y:163.32

21:34:02.270: Z-probe:8.374 X:86.66 Y:163.32

21:34:17.336: Z-probe:8.705 X:124.99 Y:163.32

21:34:32.794: Z-probe:9.035 X:163.32 Y:163.32

21:34:48.743: Z-probe:9.462 X:201.65 Y:163.32

21:35:05.309: Z-probe:9.983 X:239.98 Y:163.32

21:35:23.226: Z-probe:7.806 X:10.00 Y:124.99

21:35:37.503: Z-probe:8.029 X:48.33 Y:124.99

21:35:52.118: Z-probe:8.313 X:86.66 Y:124.99

21:36:07.071: Z-probe:8.605 X:124.99 Y:124.99

21:36:22.459: Z-probe:8.985 X:163.32 Y:124.99

21:36:38.351: Z-probe:9.407 X:201.65 Y:124.99

21:36:54.906: Z-probe:9.984 X:239.98 Y:124.99

21:37:12.826: Z-probe:7.814 X:10.00 Y:86.66

21:37:27.078: Z-probe:8.010 X:48.33 Y:86.66

21:37:41.667: Z-probe:8.283 X:86.66 Y:86.66

21:37:56.591: Z-probe:8.578 X:124.99 Y:86.66

21:38:11.893: Z-probe:8.910 X:163.32 Y:86.66

21:38:27.771: Z-probe:9.394 X:201.65 Y:86.66

21:38:44.234: Z-probe:9.904 X:239.98 Y:86.66

21:39:02.410: Z-probe:8.028 X:10.00 Y:48.33

21:39:16.854: Z-probe:8.173 X:48.33 Y:48.33

21:39:31.590: Z-probe:8.416 X:86.66 Y:48.33

21:39:46.618: Z-probe:8.670 X:124.99 Y:48.33

21:40:02.003: Z-probe:8.980 X:163.32 Y:48.33

21:40:17.936: Z-probe:9.452 X:201.65 Y:48.33

21:40:34.504: Z-probe:9.993 X:239.98 Y:48.33

21:40:52.965: Z-probe:8.263 X:10.00 Y:10.00

21:41:07.821: Z-probe:8.530 X:48.33 Y:10.00

21:41:22.882: Z-probe:8.704 X:86.66 Y:10.00

21:41:38.191: Z-probe:8.917 X:124.99 Y:10.00

21:41:53.836: Z-probe:9.208 X:163.32 Y:10.00

21:42:09.972: Z-probe:9.632 X:201.65 Y:10.00

21:42:26.754: Z-probe:10.175 X:239.98 Y:10.00

21:42:27.565: Info:Distortion correction matrix:

21:42:27.567: 917, 823, 730, 642, 536, 389, 200

21:42:27.569: 1032, 928, 818, 714, 590, 426, 244

21:42:27.570: 1062, 958, 850, 718, 586, 415, 207

21:42:27.571: 1078, 988, 875, 758, 606, 437, 206

21:42:27.573: 1075, 996, 887, 769, 636, 442, 238

21:42:27.574: 989, 931, 833, 732, 608, 419, 203

21:42:27.575: 895, 788, 718, 633, 517, 347, 130

21:42:27.578: G33 X10.00 Y10.00 Z2.237

21:42:27.581: G33 X10.00 Y48.33 Z2.472

21:42:27.582: G33 X10.00 Y86.66 Z2.687

21:42:27.585: G33 X10.00 Y124.99 Z2.695

21:42:27.585: G33 X10.00 Y163.32 Z2.655

21:42:27.586: G33 X10.00 Y201.65 Z2.580

21:42:27.589: G33 X10.00 Y239.98 Z2.292

21:42:27.590: G33 X48.33 Y10.00 Z1.970

21:42:27.593: G33 X48.33 Y48.33 Z2.327

21:42:27.595: G33 X48.33 Y86.66 Z2.490

21:42:27.595: G33 X48.33 Y124.99 Z2.470

21:42:27.597: G33 X48.33 Y163.32 Z2.395

21:42:27.599: G33 X48.33 Y201.65 Z2.320

21:42:27.601: G33 X48.33 Y239.98 Z2.057

21:42:27.603: G33 X86.66 Y10.00 Z1.795

21:42:27.606: G33 X86.66 Y48.33 Z2.082

21:42:27.606: G33 X86.66 Y86.66 Z2.217

21:42:27.607: G33 X86.66 Y124.99 Z2.187

21:42:27.610: G33 X86.66 Y163.32 Z2.125

21:42:27.611: G33 X86.66 Y201.65 Z2.045

21:42:27.614: G33 X86.66 Y239.98 Z1.825

21:42:27.617: G33 X124.99 Y10.00 Z1.582

21:42:27.617: G33 X124.99 Y48.33 Z1.830

21:42:27.618: G33 X124.99 Y86.66 Z1.922

21:42:27.621: G33 X124.99 Y124.99 Z1.895

21:42:27.622: G33 X124.99 Y163.32 Z1.795

21:42:27.625: G33 X124.99 Y201.65 Z1.785

21:42:27.627: G33 X124.99 Y239.98 Z1.605

21:42:27.629: G33 X163.32 Y10.00 Z1.292

21:42:27.631: G33 X163.32 Y48.33 Z1.520

21:42:27.631: G33 X163.32 Y86.66 Z1.590

21:42:27.633: G33 X163.32 Y124.99 Z1.515

21:42:27.635: G33 X163.32 Y163.32 Z1.465

21:42:27.638: G33 X163.32 Y201.65 Z1.475

21:42:27.639: G33 X163.32 Y239.98 Z1.340

21:42:27.642: G33 X201.65 Y10.00 Z0.868

21:42:27.643: G33 X201.65 Y48.33 Z1.047

21:42:27.643: G33 X201.65 Y86.66 Z1.105

21:42:27.646: G33 X201.65 Y124.99 Z1.092

21:42:27.648: G33 X201.65 Y163.32 Z1.037

21:42:27.650: G33 X201.65 Y201.65 Z1.065

21:42:27.652: G33 X201.65 Y239.98 Z0.972

21:42:27.654: G33 X239.98 Y10.00 Z0.325

21:42:27.656: G33 X239.98 Y48.33 Z0.507

21:42:27.657: G33 X239.98 Y86.66 Z0.595

21:42:27.658: G33 X239.98 Y124.99 Z0.515

21:42:27.660: G33 X239.98 Y163.32 Z0.518

21:42:27.663: G33 X239.98 Y201.65 Z0.610

21:42:27.664: G33 X239.98 Y239.98 Z0.500

21:42:27.666: Z correction enabled

G30

21:43:25.071: X:0.00 Y:0.00 Z:0.000 E:0.0000

21:45:25.755: Z-probe:4.779 X:0.00 Y:0.00 zCorr:2.237

21:45:53.094: X:0.00 Y:0.00 Z:2.237 E:0.0000

Not quite unrelated feature request: I'd love to be able to define a Z_MIN_HOMING switch so I don't have to ram the nozzle into the bed to reach the Z_MIN_ENDSTOP for homing. Yes, I could home against a Z_MAX switch, but two times 350 mm at 2mm/s takes a bit longer than I want to endure...

Repetier

Looks like you have a z min endstup and a z probe. That is a combination that does not work. You need to always home z min using z probe in that case. Otherwise you measure something using z probe and for homing you ignore everything and you use the not calibrated z min endstop whcih stops at a compületely different and unknown height and you can go lower even if rotation would require that.

HenryLoenwind

Repetier said:

 not calibrated z min endstop whcih stops at a compületely different and unknown height

Isn't that exactly what z-leveling is supposed to do? Measure the offset between the endstop and bed surface?

I had a quick look, and to me it seems this may not too hard to implement, in Printer::HomeZAxis():

currentPosition[Z_AXIS] = 0;

needs to be either replaced with bedleveling height at the current xy, or the axis needs to be moved up that far. And obviously this offset needs to be remembered so the next leveling can undo it to work from real coordinates.

On the other hand, putting that value into

        Printer::zBabysteps = 0;

may be the even simpler solution. No need to worry about side effects.Other than the detail that leveling compensation most probably ignores it so the bed may be out of of compensation range (only 1mm by default, I think). Also, this needs to be updated after running the leveling, but for the "detachable probe" case you do this manually and then run a print job that does homing, so it isn't that important.

I'm willing to try this out, what would be the best way to get the computed bed height? (Probably whatever G30 does, I'd guess )

Repetier

It is not so easy. z min endstop is where moves stop - no more down from that height. Soit must be at a position below bed surface (you hear the problem) otherwise you might need to go below z min trigger depending on rotation of bed. So going below bed surface means bed needs some not too hard springs or you might damage something.

This can be completely avoided by using z probe for z min. All it needs to know is x and y position so it compute backwards from known rotation what height is.

In your solution you could use bed coating to fix the gap. You need to set it manually since autoleveling levels surface but does not compute an offset to z min as this is a unsupported combination.