{"action":"created","issue":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/1885","labels_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/1885/labels{/name}","comments_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/1885/comments","events_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/1885/events","html_url":"https://github.com/MarlinFirmware/Marlin/issues/1885","id":67509326,"number":1885,"title":"Possible Servo problem, with workaround","user":{"login":"c-born","id":2059837,"avatar_url":"https://avatars.githubusercontent.com/u/2059837?v=3","gravatar_id":"","url":"https://api.github.com/users/c-born","html_url":"https://github.com/c-born","followers_url":"https://api.github.com/users/c-born/followers","following_url":"https://api.github.com/users/c-born/following{/other_user}","gists_url":"https://api.github.com/users/c-born/gists{/gist_id}","starred_url":"https://api.github.com/users/c-born/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/c-born/subscriptions","organizations_url":"https://api.github.com/users/c-born/orgs","repos_url":"https://api.github.com/users/c-born/repos","events_url":"https://api.github.com/users/c-born/events{/privacy}","received_events_url":"https://api.github.com/users/c-born/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/labels/Needs%20more%20work","name":"Needs more work","color":"fbca04"},{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/labels/Verified%20bug!","name":"Verified bug!","color":"e11d21"}],"state":"open","locked":false,"assignee":null,"milestone":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/milestones/27","html_url":"https://github.com/MarlinFirmware/Marlin/milestones/Bug%20Fixing%20Round%204","labels_url":"https://api.github.com/repos/MarlinFirmware/Marlin/milestones/27/labels","id":1184889,"number":27,"title":"Bug Fixing Round 4","description":"","creator":{"login":"boelle","id":3832239,"avatar_url":"https://avatars.githubusercontent.com/u/3832239?v=3","gravatar_id":"","url":"https://api.github.com/users/boelle","html_url":"https://github.com/boelle","followers_url":"https://api.github.com/users/boelle/followers","following_url":"https://api.github.com/users/boelle/following{/other_user}","gists_url":"https://api.github.com/users/boelle/gists{/gist_id}","starred_url":"https://api.github.com/users/boelle/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/boelle/subscriptions","organizations_url":"https://api.github.com/users/boelle/orgs","repos_url":"https://api.github.com/users/boelle/repos","events_url":"https://api.github.com/users/boelle/events{/privacy}","received_events_url":"https://api.github.com/users/boelle/received_events","type":"User","site_admin":false},"open_issues":4,"closed_issues":0,"state":"open","created_at":"2015-06-29T08:49:46Z","updated_at":"2015-06-29T11:54:19Z","due_on":null,"closed_at":null},"comments":35,"created_at":"2015-04-10T04:54:52Z","updated_at":"2015-07-10T00:19:07Z","closed_at":null,"body":"While trying to find the cause of some seemingly random Z-Probe servo motor jitter, I hooked a digital scope up to the servo signal at the motor to check for noise etc.\r\nI was surprised to find that after a move, the signal was occasionally left in the high state, rather than always low as expected.\r\nIt appears that what is happening is that with a `PROBE_SERVO_DEACTIVATION_DELAY` set to the default 300mS, and the pulse period being 20mS, depending on the pulse length and small random timing variations the servo can be detached while the signal is high, and it remains in this state.\r\nI don't know if that is a bug in the servo library or by design, not having delved into it in any depth, perhaps it is supposed to be turned off before being detached?\r\n\r\nIn any case, when I changed `PROBE_SERVO_DEACTIVATION_DELAY` to 310mS, putting the turn-off midway between the periodic pulses when the output will always be off, the signal was always left in the off state after a pulse train.\r\n\r\nI don't know if this warrants a look at the servo library or its use, or just a change to the default off delay value and a comment in the code."},"comment":{"url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/comments/120179923","html_url":"https://github.com/MarlinFirmware/Marlin/issues/1885#issuecomment-120179923","issue_url":"https://api.github.com/repos/MarlinFirmware/Marlin/issues/1885","id":120179923,"user":{"login":"thinkyhead","id":698003,"avatar_url":"https://avatars.githubusercontent.com/u/698003?v=3","gravatar_id":"","url":"https://api.github.com/users/thinkyhead","html_url":"https://github.com/thinkyhead","followers_url":"https://api.github.com/users/thinkyhead/followers","following_url":"https://api.github.com/users/thinkyhead/following{/other_user}","gists_url":"https://api.github.com/users/thinkyhead/gists{/gist_id}","starred_url":"https://api.github.com/users/thinkyhead/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/thinkyhead/subscriptions","organizations_url":"https://api.github.com/users/thinkyhead/orgs","repos_url":"https://api.github.com/users/thinkyhead/repos","events_url":"https://api.github.com/users/thinkyhead/events{/privacy}","received_events_url":"https://api.github.com/users/thinkyhead/received_events","type":"User","site_admin":false},"created_at":"2015-07-10T00:19:07Z","updated_at":"2015-07-10T00:19:07Z","body":"Ok, this branch can be used to get debug output based on leveling code as of July 9…\r\nhttps://github.com/thinkyhead/Marlin/tree/debug_G29"}}