Z Axis homing fails to come back down sometimes

chrismolloy

When I hit the z home button while zeroing my z axis, sometimes the printer raises up, but fails to come back down to zero. Just stay up. Happens about one in twenty times. The printer is working great, just seems to be some sort of random failure of the homing.

Repetier

What type of printer? Which Firmware? Homing is handled in firmware so it is not a host problem.

chrismolloy

Marlin firmware Version 1.0.2 on a Geeetech Pro C Dual extruder printer.

Jeff_T

Hi

I'm new here but also have an endstop problem. I have a delta printer which I've carefully put together from a kit.It uses arduino mega plus the ramps1.4 board and Marlin software . I've compiled the associated config file and uploaded it all successfully. I'm able to partially control the printer. The trouble I'm having is that the X endstop does not trigger. The endstop connectors are correctly set - X Max, Y Max & Z go to their correct pins.

M119 shows TRIGGERED for Z and Y axes - but not X.
So far I'm unable to get the machine to home properly - I'm guessing because it has no clue what's happening on the X axis

Can this be a software problem - or does it indicate a hardware fault? Any solutions or things to try?

thanks in advance.

chrismolloy

What does it do if you home x does it move, move a bit in the wrong direction?

chrismolloy

check your microswitch. should be using the normally closed contacts

Jeff_T

@Chris:

The endstop microswitches are identical on all axes. I checked the X axis switch with a multimeter and it works fine. I also checked the other end of the X endstop cable with the same result.

Controlling all 3 axes via the lcd : Prepare -> Move Axis -> Move 1mm -> Move X was working. Same with other axes

chrismolloy

What does it do when you home the x axis? does it mover at all?

Jeff_T

@Chris - yes it moves when I home the X axis - but shoots past the endstop - causing chaos and lots of noise.

By a process of elimination - I discovered the problem. I tried resetting the pis.h file so that Xmax became Xmin - and putting the X endstop onto Xmin jupers. Same result.

So this indicated hardware problem to me. So I took off the Ramps board and replaced the Arduino mega board and put it all back together - and reset pins.h to its original state.

Now - all good! So that's what it was - somehow 2 pins on the Arduino were blown. Do you have any idea which pins on the Arduino map to XMin and XMax? I'll use that board for another project.

OK, so now I was able to run G29.

Here are the results:

13:15:09.163 : Bed x: 50.00 y: -50.00 z: -8.72
13:15:09.975 : Bed x: 30.00 y: -50.00 z: -8.29
13:15:10.732 : Bed x: 10.00 y: -50.00 z: -7.70
13:15:11.462 : Bed x: -10.00 y: -50.00 z: -7.06
13:15:12.178 : Bed x: -30.00 y: -50.00 z: -6.41
13:15:12.900 : Bed x: -50.00 y: -50.00 z: -5.70
13:15:13.793 : Bed x: -50.00 y: -30.00 z: -6.07
13:15:14.615 : Bed x: -30.00 y: -30.00 z: -6.79
13:15:15.435 : Bed x: -10.00 y: -30.00 z: -7.45
13:15:16.258 : Bed x: 10.00 y: -30.00 z: -8.10
13:15:17.106 : Bed x: 30.00 y: -30.00 z: -8.65
13:15:17.978 : Bed x: 50.00 y: -30.00 z: -9.10
13:15:18.860 : Bed x: 50.00 y: -10.00 z: -9.47
13:15:19.678 : Bed x: 30.00 y: -10.00 z: -9.19
13:15:20.448 : Bed x: 10.00 y: -10.00 z: -8.80
13:15:21.174 : Bed x: -10.00 y: -10.00 z: -8.16
13:15:21.891 : Bed x: -30.00 y: -10.00 z: -7.49
13:15:22.611 : Bed x: -50.00 y: -10.00 z: -6.76
13:15:23.431 : Bed x: -50.00 y: 10.00 z: -7.19
13:15:24.263 : Bed x: -30.00 y: 10.00 z: -7.86
13:15:25.078 : Bed x: -10.00 y: 10.00 z: -8.45
13:15:25.885 : Bed x: 10.00 y: 10.00 z: -8.86
13:15:26.719 : Bed x: 30.00 y: 10.00 z: -9.35
13:15:27.592 : Bed x: 50.00 y: 10.00 z: -9.74
13:15:28.400 : Bed x: 50.00 y: 30.00 z: -10.00
13:15:29.260 : Bed x: 30.00 y: 30.00 z: -10.00
13:15:30.029 : Bed x: 10.00 y: 30.00 z: -9.51
13:15:30.763 : Bed x: -10.00 y: 30.00 z: -8.90
13:15:31.484 : Bed x: -30.00 y: 30.00 z: -8.21
13:15:32.213 : Bed x: -50.00 y: 30.00 z: -7.54
13:15:33.020 : Bed x: -50.00 y: 50.00 z: -7.94
13:15:33.856 : Bed x: -30.00 y: 50.00 z: -8.56
13:15:34.682 : Bed x: -10.00 y: 50.00 z: -9.19
13:15:35.511 : Bed x: 10.00 y: 50.00 z: -9.76
13:15:36.342 : Bed x: 30.00 y: 50.00 z: -10.00
13:15:37.207 : Bed x: 50.00 y: 50.00 z: -10.00
13:15:37.211 : -5.80 -6.51 -7.16 -7.80 -8.39 -8.82
13:15:37.211 : -6.17 -6.89 -7.55 -8.20 -8.75 -9.20
13:15:37.215 : -6.86 -7.59 -8.26 -8.90 -9.29 -9.57
13:15:37.219 : -7.29 -7.96 -8.55 -8.96 -9.45 -9.84
13:15:37.219 : -7.64 -8.31 -9.00 -9.61 -10.10 -10.10
13:15:37.223 : -8.04 -8.66 -9.29 -9.86 -10.10 -10.10

To me this looks bad - just on the face of it and it looks like there's a 4.3mm variation in highest and lowest points - 5.7mm to 10.

I suspect you're more clued up on what you see than I am. Does it indicate that one or more arms is too long ? On which axis? Of course the bed is perfectly flat - 3mm machined aluminium. What steps do I take to diagnose the ault?

Jeff_T

P.S. I've just run m666 levelling sequence, added some .8mm shims to the bed , ran G29 and now get:

17:00:28.622 : Bed x: 50.00 y: -50.00 z: -0.05
17:00:29.465 : Bed x: 30.00 y: -50.00 z: 0.02
17:00:30.256 : Bed x: 10.00 y: -50.00 z: 0.21
17:00:31.022 : Bed x: -10.00 y: -50.00 z: 0.36
17:00:31.776 : Bed x: -30.00 y: -50.00 z: 0.52
17:00:32.538 : Bed x: -50.00 y: -50.00 z: 0.72
17:00:33.418 : Bed x: -50.00 y: -30.00 z: 0.49
17:00:34.213 : Bed x: -30.00 y: -30.00 z: 0.29
17:00:34.991 : Bed x: -10.00 y: -30.00 z: 0.12
17:00:35.798 : Bed x: 10.00 y: -30.00 z: -0.04
17:00:36.608 : Bed x: 30.00 y: -30.00 z: -0.18
17:00:37.465 : Bed x: 50.00 y: -30.00 z: -0.30
17:00:38.325 : Bed x: 50.00 y: -10.00 z: -0.69
17:00:39.172 : Bed x: 30.00 y: -10.00 z: -0.78
17:00:39.967 : Bed x: 10.00 y: -10.00 z: -0.66
17:00:40.726 : Bed x: -10.00 y: -10.00 z: -0.46
17:00:41.476 : Bed x: -30.00 y: -10.00 z: -0.25
17:00:42.233 : Bed x: -50.00 y: -10.00 z: -0.01
17:00:43.035 : Bed x: -50.00 y: 10.00 z: -0.23
17:00:43.823 : Bed x: -30.00 y: 10.00 z: -0.36
17:00:44.593 : Bed x: -10.00 y: 10.00 z: -0.36
17:00:45.379 : Bed x: 10.00 y: 10.00 z: -0.48
17:00:46.190 : Bed x: 30.00 y: 10.00 z: -0.59
17:00:47.042 : Bed x: 50.00 y: 10.00 z: -0.68
17:00:47.857 : Bed x: 50.00 y: 30.00 z: -1.00
17:00:48.713 : Bed x: 30.00 y: 30.00 z: -1.04
17:00:49.511 : Bed x: 10.00 y: 30.00 z: -0.89
17:00:50.282 : Bed x: -10.00 y: 30.00 z: -0.70
17:00:51.039 : Bed x: -30.00 y: 30.00 z: -0.49
17:00:51.809 : Bed x: -50.00 y: 30.00 z: -0.33
17:00:52.592 : Bed x: -50.00 y: 50.00 z: -0.40
17:00:53.395 : Bed x: -30.00 y: 50.00 z: -0.54
17:00:54.186 : Bed x: -10.00 y: 50.00 z: -0.73
17:00:54.980 : Bed x: 10.00 y: 50.00 z: -0.76
17:00:55.807 : Bed x: 30.00 y: 50.00 z: -0.89
17:00:56.677 : Bed x: 50.00 y: 50.00 z: -0.96
17:00:56.677 : 0.62 0.42 0.26 0.11 -0.08 -0.15
17:00:56.680 : 0.39 0.19 0.02 -0.14 -0.28 -0.40
17:00:56.680 : -0.11 -0.35 -0.56 -0.76 -0.88 -0.79
17:00:56.684 : -0.33 -0.46 -0.46 -0.58 -0.69 -0.78
17:00:56.688 : -0.43 -0.59 -0.80 -0.99 -1.14 -1.10
17:00:56.688 : -0.50 -0.64 -0.83 -0.86 -0.99 -1.06

big improvement but not perfect. Is it within reasonable tolerances? Any recommendations?

chrismolloy

sorry, I have no experience with auto levelling. Have you levelled the bed manually first?

Jeff_T

@chris. I have been using m66 x2 m00 etc - if that is what you mean. That got me to the current situation - but it's not perfect . Is there a tutorial anywhere on bed levelling?