{"action":"created","issue":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/4577","repository_url":"https://api.github.com/repos/MarlinFirmware/Marlin","labels_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/4577/labels{/name}","comments_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/4577/comments","events_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/4577/events","html_url":"https://github.com/MarlinFirmware/Marlin/issues/4577","id":170213451,"number":4577,"title":"M851 behaves strange (nozzle crashes into bed)","user":{"login":"christianh17","id":17517578,"avatar_url":"https://avatars.githubusercontent.com/u/17517578?v=3","gravatar_id":"","url":"https://api.github.com/users/christianh17","html_url":"https://github.com/christianh17","followers_url":"https://api.github.com/users/christianh17/followers","following_url":"https://api.github.com/users/christianh17/following{/other_user}","gists_url":"https://api.github.com/users/christianh17/gists{/gist_id}","starred_url":"https://api.github.com/users/christianh17/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/christianh17/subscriptions","organizations_url":"https://api.github.com/users/christianh17/orgs","repos_url":"https://api.github.com/users/christianh17/repos","events_url":"https://api.github.com/users/christianh17/events{/privacy}","received_events_url":"https://api.github.com/users/christianh17/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/labels/Support:%20Configuration","name":"Support: Configuration","color":"006b75"}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":20,"created_at":"2016-08-09T16:37:04Z","updated_at":"2016-08-11T01:23:20Z","closed_at":null,"body":"Hello!\r\n\r\nI use a prusa I3 clone with inductive z-probe. In the past (till RC6) I used a start script like:\r\nG28 ; home all axes\r\nG92 Z1.05\r\nand the distance nozzle - bed was perfect.\r\nYesterday I decided to upgrade to the newest version (there was no issue with RC6 but I wanted to use the new one and perhpas give some feedback) and used the newest bugfix release from August 6th, in the morning.\r\n\r\nNow I have a problem with the distance nozzle-bed.\r\nThe script from above does not work any more, after G29 the nozzle raises (i think it is Z_PROBE_TRAVEL_HEIGHT which is 5 in my configuration) and when I use the G92 command this actual height is used as the starting point.\r\nSo I decided to do it the \"right\" way and want to use the M851 command to adjust the height. So I started with different tests and numbers.\r\n\r\nBut I could not get it to work.\r\nwith M851 Z -2.6 the nozzle crashes in the bed doing the first printing move and with M851 Z -2.5 there are around 2 mm space between nozzle and bed.\r\n\r\nMy settings (I stripped all comments)\r\n```cpp\r\n#define FIX_MOUNTED_PROBE\r\n#define X_PROBE_OFFSET_FROM_EXTRUDER 25  \r\n#define Y_PROBE_OFFSET_FROM_EXTRUDER 20 \r\n#define Z_PROBE_OFFSET_FROM_EXTRUDER 1   \r\n#define XY_PROBE_SPEED 8000\r\n#define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z\r\n#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)\r\n#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN\r\n#define Z_PROBE_DEPLOY_HEIGHT 0 \r\n#define Z_PROBE_TRAVEL_HEIGHT 5  \r\n#define Z_PROBE_OFFSET_RANGE_MIN -20\r\n#define Z_PROBE_OFFSET_RANGE_MAX 20\r\n```\r\nI am not sure if it is a bug or if I did a big mistake in configuration.\r\n\r\nShall I send any more information? \r\n\r\nKind regards\r\nChristian"},"comment":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/comments/239051809","html_url":"https://github.com/MarlinFirmware/Marlin/issues/4577#issuecomment-239051809","issue_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/4577","id":239051809,"user":{"login":"bgort","id":8062568,"avatar_url":"https://avatars.githubusercontent.com/u/8062568?v=3","gravatar_id":"","url":"https://api.github.com/users/bgort","html_url":"https://github.com/bgort","followers_url":"https://api.github.com/users/bgort/followers","following_url":"https://api.github.com/users/bgort/following{/other_user}","gists_url":"https://api.github.com/users/bgort/gists{/gist_id}","starred_url":"https://api.github.com/users/bgort/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bgort/subscriptions","organizations_url":"https://api.github.com/users/bgort/orgs","repos_url":"https://api.github.com/users/bgort/repos","events_url":"https://api.github.com/users/bgort/events{/privacy}","received_events_url":"https://api.github.com/users/bgort/received_events","type":"User","site_admin":false},"created_at":"2016-08-11T01:23:20Z","updated_at":"2016-08-11T01:23:20Z","body":"Formatted with both CR+LF, in case the previous version is a mess.\r\n\r\n[serial-crlf.txt](https://github.com/MarlinFirmware/Marlin/files/412427/serial-crlf.txt)\r\n"}}
{"actor":{"display_login":"bgort"}}