Z Compensation

Z compensation

klippy/extras/z_compensate.py — per-print auto-Z-offset tuning. This is new code, not a port — Creality's real z_compensate_wrapper.so has no published source anywhere we could find, so this module's design was worked out from strong reverse-engineering evidence (it delegates into PRTouch's own primitives, and its bl_offset config value matches [bltouch]'s own y_offset exactly).

It runs once per print, before bed-mesh calibration — a per-print thermal/wear fine-tune, not a one-time factory calibration. By default it applies the correction as a live SET_GCODE_OFFSET for that session; making it permanent is opt-in (persist_offset), since baking it straight into the saved probe z_offset via SAVE_CONFIG would trigger a Klippy restart mid-print, which is obviously not what you want.

The XY-reference fix got live-qualified alongside PRTouch's own — same underlying correction, applied here too.

It exposes structured status (not gcode text) through Klipper's normal object-status/webhooks mechanism, so GuppyScreen and Moonraker can poll it programmatically instead of parsing command output.

One thing that looks like a mistake but isn't: [z_compensate] has its own tri_min_hold/ tri_max_hold values, separate from [prtouch_v2]'s — that's a genuine per-feature sensitivity tune, not a duplicate.

See also: PRTouch, NebulaOS Changes.