diff --git a/Marlin/src/gcode/calibrate/G34_M422.cpp b/Marlin/src/gcode/calibrate/G34_M422.cpp index fee9ea2189..101b3cc008 100644 --- a/Marlin/src/gcode/calibrate/G34_M422.cpp +++ b/Marlin/src/gcode/calibrate/G34_M422.cpp @@ -142,6 +142,8 @@ void GcodeSuite::G34() { z_maxdiff = 0.0f, amplification = z_auto_align_amplification; + const ProbePtRaise raise_after = parser.boolval('E') ? PROBE_PT_STOW : PROBE_PT_RAISE; + uint8_t iteration; bool err_break = false; for (iteration = 0; iteration < z_auto_align_iterations; ++iteration) { @@ -159,18 +161,18 @@ void GcodeSuite::G34() { // Safe clearance even on an incline if (iteration == 0 || izstepper > 0) do_blocking_move_to_z(z_probe); - // Probe a Z height for each stepper - if (isnan(probe_pt(z_auto_align_xpos[zstepper], z_auto_align_ypos[zstepper], PROBE_PT_RAISE, 0, true))) { + // Probe a Z height for each stepper. + const float z_probed_height = probe_pt(z_auto_align_xpos[zstepper], z_auto_align_ypos[zstepper], raise_after, 0, true); + if (isnan(z_probed_height)) { SERIAL_ECHOLNPGM("Probing failed."); err_break = true; break; } - // This is not the trigger Z value. It is the position of the probe after raising it. - // It is higher than the trigger value by a constant value (not known here). This value - // is more useful for determining the desired next iteration Z position for probing. It is - // equally well suited for determining the misalignment, just like the trigger position would be. - z_measured[zstepper] = current_position[Z_AXIS]; + // Add height to each value, to provide a more useful target height for + // the next iteration of probing. This allows adjustments to be made away from the bed. + z_measured[zstepper] = z_probed_height + Z_CLEARANCE_BETWEEN_PROBES; + if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPAIR("> Z", int(zstepper + 1), " measured position is ", z_measured[zstepper]); // Remember the minimum measurement to calculate the correction later on