Endstops triggered even when unplugged

foesi

Hallo,

I have now set up my Duet 3 mini 5+ and after trying everything I wanted to make a test print.
The next day I heated up the bed and wanted to home the axis for z-probe offset...
The X- and Y-stop then did not work or to be precise they did trigger right away.
Then I tried to use the IO_2 and the IO_4 port instead of the IO_0 and the IO_1 - same problem.
After that I converted the pinname with a "!" like P"!io.0in". That made the endstopps to not trigger regardless of what I tried.
It made no difference if the endstopps were connected or not.
The thing is... they worked the day before so there should not be a wiring or configuration problem!?
I also checked the voltage of the IO pins and the 5V to GND and 3.3V to GND were both fine on all IOs.

To update the firmware did also not change anything.

Here is some more information:

Board: Duet 3 Mini 5+ (Mini5plus)
Firmware: RepRapFirmware for Duet 3 Mini 5+ 3.4.1 (2022-06-01)
Duet WiFi Server Version: 1.26

config.g definition:

M574 X1 S1 P"io0.in"
M574 Y1 S1 P"io1.in"
M574 Z1 S2

The z-probe works - for some reason.

Thanks in advance!

jay_s_uk

@foesi can you show how you have them wired please

foesi

@jay_s_uk I have connected one wire with the 5V of the IO port and the other wire with the ioX_in. Same on both X- and Y endstops. Only Z is wired to 12V in the middle of the board and only the signal wire is connected to the io3_in. I need this because the z-probe needs 6V+.

jay_s_uk

@foesi then you've wired them wrong. They should be connected between ground and iox.in

foesi

@jay_s_uk thanks for the reminder to try this - and it was indeed the problem.
But why did my wiring work the day before for at least homing 10 times? It doesn´t really matter now but I am just curious...

jay_s_uk

@foesi very good question which i don't have the answer for

deckingman

@foesi If an input isn't tied to either high or gnd, it will be floating. That is to say, it'll be prone to picking up stray RF etc which can make it flip around from high to low or vice versa, somewhat at random. So you might get lucky with the input reading the correct value at the right time, or you might get unlucky. The end stop status is only read by the firmware during a homing move, so you wouldn't normally see this random flip-flopping.