Auto leveling grid error

I have a cartesian printer with an inductive sensor for z probing. I use an z max endstop as well. The whole auto-leveling procedure upon sending m32 Sx works. The sensor probes at 5x5 points and a transformation matrix appears in the log. Afterwards the z axis moves with x and y movements. But when I start printing sometimes the nozzle still hits the bed. I am pretty sure this has something to do with a wrong matrix which is the result of an error in the probing procedure.

After probing the last point of the grid, the carriage moves an extra amount away from xmin. The x location reported in repetier host does not change however (sometimes is even becomes a couple decimals lower). So when I move the carriage back to xmin it hits zero (in repetier host) before hitting the actual endstop. Why is this extra x move made after the probing? And why is the x location wrong after the probing? I have checked for mechanical causes but there is no slipping, blocking etc. Furthermore the extra distance is always the same. The extra move does not occur in y direction.

I suspect is has something to do with the probe xy offset. There is no y offset. There is only a x offset of +31.5 (the probe is located 31.5mm to the right of the extruder with xmin at the left of the bed). 

What is going wrong here? I hope someone can help.


  • Btw, I am using the newest firmware version, 0.92.x. Downloaded today with the configuration tool.
  • Go to middle of bed near bed and do
    G30 P3

    you should see x move to probe position, z probe and then back move. G32 does the same but you need to start where that move is possible (so probably not x = 0). So I think that move was prevented but stored as offset and undone after probing resulting in a wrong position.

    Also note that there is a problem with G32 so that z after probing is wrong and only z max homing would fix that. Will be fixed soon in dev version (which is the newest).
  • Indeed if I send G32 with the nozzle at the bed center the position is correct after the procedure. A final move afterwards is still made however. I think this move makes the nozzle go to the last position of the probe was at. So in my case to X185. 

    Here's the log during the autoleveling. The first to moves are done manually do move to the center. The very last move is done automatically after the leveling.

    17:40:48.369 : N130 G1 X95 F2400*62
    17:40:48.369 : N131 G1 Y100 F2400*3
    17:40:48.369 : N132 G32 S2*89
    17:40:48.369 : Info:Autoleveling disabled
    17:40:49.339 : N133 M105*38
    17:40:52.403 : N134 M105*33
    17:40:55.441 : N135 M105*32
    17:40:58.526 : N136 M105*35
    17:41:01.546 : N137 M105*34
    17:41:04.618 : N138 M105*45
    17:41:07.656 : N139 M105*44
    17:41:10.727 : N140 M105*34
    17:41:13.764 : N141 M105*35
    17:41:16.834 : N142 M105*32
    17:41:19.922 : N143 M105*33
    17:41:19.976 : Z-probe:4.43 X:36.50 Y:10.00
    17:41:22.975 : N144 M105*38
    17:41:24.783 : Z-probe:4.41 X:36.50 Y:55.00
    17:41:26.048 : N145 M105*39
    17:41:29.121 : N146 M105*36
    17:41:29.606 : Z-probe:4.43 X:36.50 Y:100.00
    17:41:32.190 : N147 M105*37
    17:41:34.447 : Z-probe:4.46 X:36.50 Y:145.00
    17:41:35.248 : N148 M105*42
    17:41:38.240 : N149 M105*43
    17:41:39.311 : Z-probe:4.46 X:36.50 Y:190.00
    17:41:41.283 : N150 M105*35
    17:41:45.214 : Z-probe:4.72 X:73.62 Y:10.00
    17:41:50.365 : Z-probe:4.72 X:73.62 Y:55.00
    17:41:55.554 : Z-probe:4.75 X:73.62 Y:100.00
    17:42:00.695 : Z-probe:4.76 X:73.62 Y:145.00
    17:42:05.882 : Z-probe:4.82 X:73.62 Y:190.00
    17:42:12.184 : Z-probe:4.98 X:110.75 Y:10.00
    17:42:17.555 : Z-probe:4.97 X:110.75 Y:55.00
    17:42:22.919 : Z-probe:4.99 X:110.75 Y:100.00
    17:42:28.345 : Z-probe:5.04 X:110.75 Y:145.00
    17:42:33.850 : Z-probe:5.10 X:110.75 Y:190.00
    17:42:40.312 : Z-probe:5.21 X:147.88 Y:10.00
    17:42:45.925 : Z-probe:5.23 X:147.88 Y:55.00
    17:42:51.566 : Z-probe:5.26 X:147.88 Y:100.00
    17:42:57.239 : Z-probe:5.32 X:147.88 Y:145.00
    17:43:03.018 : Z-probe:5.38 X:147.88 Y:190.00
    17:43:09.755 : Z-probe:5.40 X:185.00 Y:10.00
    17:43:15.556 : Z-probe:5.42 X:185.00 Y:55.00
    17:43:21.435 : Z-probe:5.46 X:185.00 Y:100.00
    17:43:27.320 : Z-probe:5.50 X:185.00 Y:145.00
    17:43:33.332 : Z-probe:5.59 X:185.00 Y:190.00
    17:43:36.096 : plane: a = 0.0070 b = 0.0007 c = 4.1501
    17:43:36.102 : Transformation matrix: 0.999976 0.000000 -0.006979 -0.000005 1.000000 -0.000686 0.006979 0.000686 0.999975
    17:43:36.102 : CurrentZ:5.35 atZ:5.20
    17:43:36.102 : Z after rotation:5.20
    17:43:36.102 : Printer height:181.90
    17:43:36.459 : Info:Autoleveling enabled
    17:43:37.277 : X:184.96 Y:190.00 Z:6.773 E:0.0000

  • The last move is deactivating z probe so extruder nozzle goes where z probe was. That is correct.

    dev version now contains fixes I talked about.
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