Endstops immediately triggered

stogger

Hello,

I'm building a CoreXY 3D printer with the following setup:

Board: Duet 3 MB6HC (MB6HC)
Firmware: RepRapFirmware for Duet 3 MB6HC 3.3 (2021-06-15)
Endstops: Optical endstops RAMPS 1.4

In my homex.g I have the following code:

;*******************************************************************************
;** Then home the X-axis
;*******************************************************************************
G1 H1 X-1000 F3000 ; Move quickly to X axis end-stop
G1 H0 X10 F300 ; Go back a few mm
G1 H1 X-100 F300 ; Move slowly to X axis end-stop

In my config, the endstops are declared as follows:

M574 X1 S1 P"io0.in" ; Configure X-axis endstop
M574 Y1 S1 P"io1.in" ; Configure Y-axis endstop

I run my endstops at 5Vdc.

I have another printer with the same setup and exactly the same homex.g file. I have no problems homing any axes on this printer, The new one however, triggers the endstops immediately when executing the G1 H1 commands, regardless of the actual position of my hotend. The M119 command confirms the endstops being triggered.

The endstops are active high. They are connected correctly and when I measure directly at the endstops input pins, it measures 0,6Vdc when not triggered and 5Vdc when triggered. These voltages correspond with the voltages measured at the working printer.

I have checked both printers for differences in wiring and gcode, but in my eyes everything matches up perfectly. I've been troubleshooting for hours now but so far I've come up with nothing.

If you guys have any suggestions to fix the issue, I would be most grateful. It would be nice to let the printer travel to its actual home position. I hope I supplied enough information to go on.

jay_s_uk

@stogger have you tried inverting the endstops?
what does M119 report if you send it when one of the endstops is triggered?

stogger

@jay_s_uk

Endstops - X: at min stop, Y: at min stop, Z: not stopped, Z probe: not stopped

jay_s_uk

@stogger and without an endstop triggered? if its the same then you've wired them wrong

stogger

@jay_s_uk

I noticed from text I shared with you that both X and Y were homed according to M119, even though I only homed X. Sure enough I got a couple different results with the M119 command from a couple of cycles of running it before homing, only one axis homed and both axes homed.

I decided to get the old multimeter out and sure enough, there was a varying voltage difference between multiple grounds as a result of poor wiring. After a quick and dirty shorting of all grounds, the endstops work just fine.

Guess it's one of the perks of inheriting a project...