Induction probes have one fault. A power on or off cycle of the bed heater can interfere with the probe, leading to a false/inaccurate reading.
I currently circumvent this by creating bed meshes with bangbang heating, and during z homing temporarily disabling the heater. Bangbang heating works as it lowers the amount of switching, and therefore the chance of interfering with the probe.
Changing PID PWM settings unfortunately does not fix this.
Umfortunately, klipper does not allow changes to the type of bed heating algorithm using macros.
Workarounds include elaborate shell command scripts, or manual editing of the config.
For obvious reasons bangbang should not be used during printing, so switching back and forth between these algorithms is currently necessary.
My feature request would be one or multiple of the following:
-Disabling the heater upon second/the more precise probing retries.
-Allowing to switch between heater algorithms over macros without elaborate trickery
I’ve never seen this and I’m running induction probes on all five of my printers. I’ve used several different part numbers from various manufacturers - both on system power (24V) and 5V.
I’m wondering if you have a marginal power supply or grounding issues. How many printers have you seen this on?
A couple.
It “helps” to have a really large bed. I suspected the power supply being too weak at first, but for the machine I own myself and can test this on this happens to not be the case. No voltage fluctuations, and the power supply is at 80% of its nominal capacity.
If you have a large bed with an inductive probe, try the probe accuracy command with PID and with bang bang. It goes from 0.04mm variation between the lowest and highest reading (bangbang) to 0.1mm (pid) for me.
This is a known effect, since the bed heater is strongly emitting electromagnetic interferences due to high currents, due to its “antenna” design and due to rapid PWM.