'no trigger on stepper_z after full movement’

General Discussion
1

Basic Information:

Printer Model: Own design and build.
MCU / Printerboard: Octopus Pro (STM32F429)
Host / SBC - RPi5
klippy.log:

klippy-3.log (52.1 KB)

I know this problem has been encountered by others, but all the suggestions I have seen thus far have not worked for me.

The machine is one I designed and built myself. It has evolved through a number different iteration into its present form. I had not encountered this particular problem until my latest upgrades. All the upgrades were to hardware. 9mm linear rails to 12 mm, revised hot end carriage etc. I also went from a Pi 4 to a Pi 5. This did require me to reinstall the firmware of course, but I made no change to the printer.cfg or macros.cfg files. At no time during the development of this printer didi I encounter problems homing the z-axis. Until now that is.

Machine specs that may be of significance are: Build volume 400 x 400 x 360. I use four stepper motors for the z-axis and a piezo load cell probe. Limits set for z are -5 min to 360 max.

What I don’t get is how it determines it has made full movement. Until it has homed, surely it has no idea where it is in space!

As I say, I have just performed upgrades on this machine, but it has stood idle for months now due to this problem! :worried:

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2

Hi @BoomerT6 ,

What happens when you try to home Z? Does the nozzle crash into the bed, or does the nozzle never reach it? What probe are you using?

If you use the QUERY_PROBE command, does the probe properly show as TRIGGERED when you press it (or move it close to the bed if it’s an inductive probe)?

What Klipper does is it will move 1.5x the total distance you configured the axis can move, so in your setup, 360 - (-5) = 365mm of movement, so Klipper will attempt to move 547.5mm during the Z home.

3

Hi 3dcoded,
It never reaches the bed. I’m using a Precision Piezo Orion PCB for the probe.
With the QUERY_PROBE command, it shows as ‘open’, with the red probe LED lite. A blue LED indicates it is triggered. A light tap on the probe will trigger it. This functions as required.

I forgot to mention this is a core XY machine.
When I initiate the home command, the bed first drops 15mm. It then homes X and Y, before moving the nozzle back to the centre of the bed, where it drops the bed a further 5mm before raising the bed towards the nozzle. It travels just 10mm then I get the 'no trigger on stepper_z after full movement’ message. In the past, the bed kept going until it met the nozzle and the probe triggered, but not any more.