G29 crashes into bed and returns error

[whudson]

Here is a video showing what happens. The crash happens at 1:50.

Here is my serial log.

11:22:27.707 : N15 G29 V3*99
11:22:27.707 : G29 Auto Bed Leveling
11:22:29.804 : echo:busy: processing
11:22:31.801 : echo:busy: processing
11:22:33.807 : echo:busy: processing
11:22:35.804 : echo:busy: processing
11:22:36.299 : Bed X: 0.000 Y: -55.000 Z: 0.104
11:22:37.805 : echo:busy: processing
11:22:39.801 : echo:busy: processing
11:22:39.917 : Bed X: 37.000 Y: -37.000 Z: 0.548
11:22:41.806 : echo:busy: processing
11:22:43.189 : Bed X: 18.000 Y: -37.000 Z: -0.075
11:22:43.803 : echo:busy: processing
11:22:45.806 : echo:busy: processing
11:22:46.288 : Bed X: 0.000 Y: -37.000 Z: 0.135
11:22:47.803 : echo:busy: processing
11:22:49.376 : Bed X: -18.000 Y: -37.000 Z: 0.169
11:22:49.802 : echo:busy: processing
11:22:51.804 : echo:busy: processing
11:22:52.546 : Bed X: -37.000 Y: -37.000 Z: 0.487
11:22:53.803 : echo:busy: processing
11:22:55.804 : echo:busy: processing
11:22:55.844 : Bed X: -37.000 Y: -18.000 Z: 0.109
11:22:57.804 : echo:busy: processing
11:22:59.037 : Bed X: -18.000 Y: -18.000 Z: 0.040
11:22:59.804 : echo:busy: processing
11:23:01.805 : echo:busy: processing
11:23:02.151 : Bed X: 0.000 Y: -18.000 Z: 0.177
11:23:03.805 : echo:busy: processing
11:23:05.260 : Bed X: 18.000 Y: -18.000 Z: 0.110
11:23:05.805 : echo:busy: processing
11:23:07.803 : echo:busy: processing
11:23:08.452 : Bed X: 37.000 Y: -18.000 Z: 0.272
11:23:09.805 : echo:busy: processing
11:23:11.800 : echo:busy: processing
11:23:11.920 : Bed X: 55.000 Y: 0.000 Z: 0.329
11:23:13.803 : echo:busy: processing
11:23:15.255 : Bed X: 37.000 Y: 0.000 Z: -0.015
11:23:15.799 : echo:busy: processing
11:23:17.804 : echo:busy: processing
11:23:18.442 : Bed X: 18.000 Y: 0.000 Z: 0.210
11:23:19.804 : echo:busy: processing
11:23:21.579 : Bed X: 0.000 Y: 0.000 Z: 0.049
11:23:21.941 : echo:busy: processing
11:23:23.949 : echo:busy: processing
11:23:24.657 : Bed X: -18.000 Y: 0.000 Z: 0.350
11:23:25.947 : echo:busy: processing
11:23:27.885 : Bed X: -37.000 Y: 0.000 Z: 0.148
11:23:28.087 : echo:busy: processing
11:23:30.087 : echo:busy: processing
11:23:31.195 : Bed X: -55.000 Y: 0.000 Z: 0.292
11:23:32.086 : echo:busy: processing
11:23:34.094 : echo:busy: processing
11:23:34.537 : Bed X: -37.000 Y: 18.000 Z: 0.148
11:23:36.092 : echo:busy: processing
11:23:37.742 : Bed X: -18.000 Y: 18.000 Z: 0.020
11:23:38.117 : echo:busy: processing
11:23:40.125 : echo:busy: processing
11:23:40.852 : Bed X: 0.000 Y: 18.000 Z: 0.333
11:23:42.122 : echo:busy: processing
11:23:43.992 : Bed X: 18.000 Y: 18.000 Z: 0.109
11:23:44.188 : echo:busy: processing
11:23:46.190 : echo:busy: processing
11:23:47.254 : Bed X: 37.000 Y: 18.000 Z: 0.241
11:23:48.189 : echo:busy: processing
11:23:50.187 : echo:busy: processing
11:23:50.502 : Bed X: 37.000 Y: 37.000 Z: 0.054
11:23:52.186 : echo:busy: processing
11:23:53.789 : Bed X: 18.000 Y: 37.000 Z: 0.122
11:23:54.188 : echo:busy: processing
11:23:56.191 : echo:busy: processing
11:23:56.927 : Bed X: 0.000 Y: 37.000 Z: 0.241
11:23:58.192 : echo:busy: processing
11:24:00.096 : Bed X: -18.000 Y: 37.000 Z: 0.223
11:24:00.292 : echo:busy: processing
11:24:02.298 : echo:busy: processing
11:24:03.431 : Bed X: -37.000 Y: 37.000 Z: 0.049
11:24:04.368 : echo:busy: processing
11:24:06.025 : Bed X: 0.000 Y: 55.000 Z: NaN
11:24:06.030 : Error:Probing failed
11:24:06.035 : X:0.00 Y:55.00 Z:1.40 E:0.00 Count X:7566 Y:7529 Z:13938

[aegean-odyssey]

From the data, it looks like the nozzle is getting hung up before it reaches the bed. I think this issue is a duplicate of issue #11. If not, please follow up and keep this issue open.

Though the G29 command couldn't sample the last point, it is followed by a G29 C1 which will ignore missing data when computing a bed level mesh. So the process does produce a valid set of calibration parameters. Just be sure to home the printer afterwards to sync up the stepper motors.

Also, a G29 L-50 R50 F-50 B50 V3 should make the test grid a little smaller, though I've not tested using the G29 command in this way.

Specs for the printer claim a build radius of 55mm, but on some printers it doesn't seem to be the case. I think the nozzle sits a bit high on these printers and allows the carriage to collide with the bed retaining pin. Though it is ugly, I prefer that the initial setup of the printer detects this situation so the user is aware that the printer is not quite up to spec.

[whudson]

Ah, my apologies. I somehow missed that issue. I will try this, it does sound like the same problem.

[whudson]

Yes that was the issue, and your suggested G29 command worked too. Thank you.