Marlin upgrade - Z axis steps problem

Hi guys,

I updated the Marlin version on my Prusa i3 because the version I was using didn't have support for autolevel bed, and since I installed it already I'm really really looking forward to try it out

The problem is that, even after editing Configuration.h to look like my old version except for the new features, my Z axis is not behaving properly. If I try to move it up by 10mm, it moves something like 2mm very fast and then the motors stop and get noisy. It's as if my DEFAULT_AXIS_STEPS_PER_UNIT were too high for the Z axis, but this is the calculated value Weirdly, this is a very similar behavior to when I had forgotten to set the jumpers for 1/16 microstepping.

#define DEFAULT_AXIS_STEPS_PER_UNIT   {78.4313, 78.4313, 4000, 625.7068}

Those are the values that worked perfectly with the older version (I'm using M5 rods, 200 steps Nema 17), but now they only seem to be working with X, Y and E.

Any ideas? Any help will be greatly appreciated.

Cheers!

Edited 1 time(s). Last edit at 02/01/2014 09:04AM by Egar.

Sounds like your acceleration is too high. That setting should be in the same area as the steps.

I had the same problem when moving z in -. It would stop and buzz. The feed rate in MArlin was set at something like 500 mm/min. I changed this to a max of 125 mm/min and now it runs fine in both directions.

Hi guys,

Thanks for the answers. I'm going to try changing both settings, but I think there's something else broken because I re-uploaded the old version of Marlin to the arduino and the problem persists.

I think the driver is busted, or a wire got cut. It's weird though, if I leave one motor connected, it moves ok, but when I attach the second one they both do the thing I described initally.

Has anyone seen this problem?

Do they both work separately? If so ot may be your current setting on the driver.

Ok, after disconnecting and reconnecting everything, trying motors and drivers independently, I got it working again thanks to your help guys, thank you very much! I adjusted both the acceleration and the feed rate. The feed rate is what did the trick. I reduced it from 5 to 2.5 and now the motors move again -apparently- correctly.

So, it works, but I still don't know why it worked before. Does this mean something broke? Anyway, I'm going to try my first auto-leveled print now. Wish me luck!

Thanks again, cheers.