Problem with X endstop

demigh0d

I did a complete rebuild/upgrade of my printer and have run into a snag with the X endstop.

Both the X and Y endstops are the same (sainsmart optical), wired the same and configured the same.

The Y endstop works fine.

On power up they both show (in the web interface) not hit, as they should.

If I trigger the X stop it shows hit.

If I untrigger the X stop it stays hit. If I unplug the X stop completely it stays hit.

The led on the endstop turns on/off as it should.

Any ideas?

[[language]]
M574 X1 Y1 S1

Duet Ethernet 1.0 + DueX5
1.19beta11 (2017-07-25)

demigh0d

Possibly a webUI bug because the x stop IS working but its status is not being updated n the webUI (under settings > machine properties).

dc42

It's normal for the endstop to show as hit when you unplug it when using S1.

What I suspect is happening is that the endstop is marginal when run from 3.3V. When not triggered, it is pulling the endstop input low enough to light the LED but not low enough to be registered reliably as triggered by the processor. The remedy is to reduce the IR LED series resistor on the endstop board as I describe at https://duet3d.com/wiki/Connecting_endstop_switches#3.3V-compatible_optical_endstop. If the series resistor is an SMD type, you may find it easier to solder another one on top (so in parallel) rather than replace the existing one.