UMS5 Incorrect z height after resuming a paused print

[glx 26]

Hi, 

I had it happening a few times now that my S5 didn’t return to the correct z height after it resumed from a paused print (caused by empty filament if that matters). It continued too low (I’d say about 0.5mm) and dragged through the whole print destroying it. It doesn’t happen all the time so I can’t provoke that behavior.
The first time I thought I probably touched the build plate and dislocated it but it happened three more times on other prints and I’m sure I didn’t touch anything. 
Is it probably becoming inaccurate when moving the quite heavy bed that much and fast or what could cause that issue? Probably moving just a few centimetres away would be enough when it pauses instead of going all the way down 🤔. 

[Carla_Birch 116]

Hi,

 

I had this problem before on one of my S5's and when the ben lowered i would hear it make like a knocking sound i had never heard before (it started to make the same sound when it was doing auto leveling at the start also).

 

It turned out that the z limit switch at the bottom of the z was to low and the print bed was hitting bottom before the limit switch fully what meant it was not getting the same z=0 each time.

 

So i lossen the limit switch off and made sure it was as high as it could go and then tighten it back up, my guess is i might have knocked it when cleaning the printer or something.