Z Homing Issue Possible Loadcell interference?
Hi, Im getting this issue now, I remember it was being discussed a while back but I cant find any definitive resolution.
When I have the bed on my Core One low, like when a print has finished, if I try homing the printer with the heaters on, I get homing failure, the printer reboots and gives an angry red screen. Before it fails, the bed starts moving up, and keeps stopping, exactly how it behaves like if the nozzle is being pressed.
Homing with the heaters off succeeds every time. Loadcell test passes fine.
It would seem that having the heaters on confuses the hell out of the Loadcell, some workarounds include disabling heating during homing in Gcode, etc. Im not interested in doing that, I want a fix not a workaround.
I think I remember some users replaced the main wiring loom from the loveboard to the buddy board, I might be misremembering that though.
There's a GitHub issue here describing what I'm seeing exactly:
https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/4596
Anyone had the issue and solved it?
Just wanted to check before I contact support.
Best Answer by k1mu:
The issue is that the shared ground on the Love Board and the noisy nature of the PCM-controlled heater current causes noise that confuses the loadcell.
Yes, some have fixed this with gcode that turns off the heat while homing. Others have removed the extruder cable and twisted the wires feeding the heater. (That's what I did.)
See this thread for an extended discussion:
https://forum.prusa3d.com/forum/prusa-core-one-assembly-and-first-prints-troubleshooting/z-axis-trouble-but-only-when-printing
What I would do is to contact Support. Get them to replace the extruder cable.
RE: Z Homing Issue Possible Loadcell interference?
The issue is that the shared ground on the Love Board and the noisy nature of the PCM-controlled heater current causes noise that confuses the loadcell.
Yes, some have fixed this with gcode that turns off the heat while homing. Others have removed the extruder cable and twisted the wires feeding the heater. (That's what I did.)
See this thread for an extended discussion:
https://forum.prusa3d.com/forum/prusa-core-one-assembly-and-first-prints-troubleshooting/z-axis-trouble-but-only-when-printing
What I would do is to contact Support. Get them to replace the extruder cable.
RE: Z Homing Issue Possible Loadcell interference?
The issue is that the shared ground on the Love Board and the noisy nature of the PCM-controlled heater current causes noise that confuses the loadcell.
Yes, some have fixed this with gcode that turns off the heat while homing. Others have removed the extruder cable and twisted the wires feeding the heater. (That's what I did.)
See this thread for an extended discussion:
https://forum.prusa3d.com/forum/prusa-core-one-assembly-and-first-prints-troubleshooting/z-axis-trouble-but-only-when-printingWhat I would do is to contact Support. Get them to replace the extruder cable.
Yep I found that thread after I created this one.
I contacted supported this morning with a quick video of the issue, a link to that thread you posted, and they're sending me a new cable harness...took around 5 minutes.
It seems pretty conclusive from reading that thread that replacing the cable solves the issue, so I'm confident I'll resolve it next week when the cable arrives...cheers for replying nonetheless.
RE:
Interesting I started having the same issue (just once though). I think one solution was to remove and twist the 4 heater wires before the connector as 2 sets of twisted pairs. The INDX will hopefully arrive (soon) and this won't be an issue anymore (I hope).
RE: Z Homing Issue Possible Loadcell interference?
Interesting I started having the same issue (just once though). I think one solution was to remove and twist the 4 heater wires before the connector as 2 sets of twisted pairs. The INDX will hopefully arrive (soon) and this won't be an issue anymore (I hope).
I had it quite intermittently, now its doing it maybe 40% of prints, it's becoming a PITA.
I wanted to get all my issues with the printer ironed out as my warranty is up in a month or so (I would have an extra 12 months but many of my compatriots decided it would be a good idea to leave the EU!)
I honestly cant be hassled with de-pinning those clik-mate connectors so I'll just use the gcode trick until my cable arrives.
I'd still like to know if the entire wiring harness is going to be replaced with INDX? I asked in Discord but no-one could give a definitive answer.
RE: Z Homing Issue Possible Loadcell interference?
I'd still like to know if the entire wiring harness is going to be replaced with INDX? I asked in Discord but no-one could give a definitive answer.
Interesting question. I guess we will find out in 3 weeks (if the schedule holds).
RE: Z Homing Issue Possible Loadcell interference?
just a reminder ... any mechanical tension on the wires to the hotend (plus friction = hysteresis) appears on the loadcell. Electrical problems are real, but there is also plain dumb wire tension, and that's easily fixed..
RE: Z Homing Issue Possible Loadcell interference?
It’s definitely not tension related mate. Easy to rule that out as when the nozzle heater is off it homes perfectly.