I’ve recently ran into issues with the auto home not working all of the time on my duel end stop burley MPCNC. When it fails it will jog towards the switches, never hits either switch and then jogs away from the switches about 10mm and stops. The z axis is also giving me intermittent issues. Sometimes it will go down towards the touch plate initially like it should and other times it goes in the up direction. After a simple restart it sometimes works properly. I reflashed the firmware and I’m still having issues. I checked all of the switches back to the RAMPS board and they all check out fine… Anyone ever run into this issue? Any ideas on a solution?
Has it ever worked correctly for you or is this a new issue? I vaguely remember on my first build having an issue where I would try to auto home, x or y and it would behave similar to what you’re describing. If I remember correctly it may have been caused because either I hadn’t defined how large my build area was or there was a preset travel limit for auto homing. So my build was roughly 600mm x 600mm, if I parked the core in the center, the preset travel distance for auto home might be 200 mm, I’d have to home twice to hit the end stops. I’ve since rebuilt and reconfigured my Marlin so I can’t recall exactly what I did to fix it. Sorry for the non-answer but you might try looking through the configuration.h file depending on what version of firmware you’re running.
If it was working correctly and this is a new issue then ignore everything I just said.
It’s a new issues. It worked without a hitch for about a year.
Next guess would be bad connections on the switches, if you’ve lengthened the cables or changed connections, I’ve heard of bad dupont connectors causing issues, another option might be noise on those lines causing the switches to trigger.
I believe I can tell you what is happening, but I have only a guess as to why. If you’ve watched your machine home, it closes the endstop switch, backs up, and then retests. Now imagine you are getting false signals that the indicate the you have reached the endstop. It would just stop and then backup for the retest. If it still senses an endstop, and just quits. The Z is the same way. If when you home, it thinks it is already home, it will backup for the retest.
Assuming this is the behavior you are seeing, then two causes (and there may be more) are 1) faulty wiring, and 2) noise.
I know one person who had a similar problem. He traced his to noise, and he solved his issue by uncommenting the following line in configuration.h and reflashing the firmware:
//#define ENDSTOP_NOISE_THRESHOLD 2
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After defining the “noise threshold” line and changing the value to “2” it seems to have taken care of the issue! Thanks for the help!!!
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