marlin2_a10m/Marlin/src/gcode/probe/M851.cpp
Scott Lahteine 3bba7d60f3 No retroactive changes with M851 Z
If using babystep to adjust the Z probe offset, the axis will move and the mesh will be updated at the same time, causing a doubling of the Z offset over the rest of the print.

To correct for this, the current Z position would need to be modified in the opposite direction, canceling out the additional Z offset added to the mesh. This would be confusing to users, and moreover it would not be accurate without also taking the current Z fade level and current Z height into account.

It might make sense to change the mesh in the case where no babystepping is taking place, but this could be considered an undesirable side-effect of changing the `zprobe_zoffset`.

One way to remedy this would be to return to storing the mesh with `zprobe_zoffset` included, then subtracting `zprobe_zoffset` from the returned Z value. Thus, a babystep moving the Z axis up 1mm would subtract 1 from `zprobe_zoffset` while adding 1 to all mesh Z values.

Without including the `zprobe_zoffset` in the `z_values` there is no safe way to alter the mesh in conjunction with babystepping, although it's fine without it.
2017-11-18 03:36:39 -06:00

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C++

/**
* Marlin 3D Printer Firmware
* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include "../../inc/MarlinConfig.h"
#if HAS_BED_PROBE
#include "../gcode.h"
#include "../../feature/bedlevel/bedlevel.h"
#include "../../module/probe.h"
void GcodeSuite::M851() {
SERIAL_ECHO_START();
SERIAL_ECHOPGM(MSG_ZPROBE_ZOFFSET " ");
if (parser.seen('Z')) {
const float value = parser.value_linear_units();
if (WITHIN(value, Z_PROBE_OFFSET_RANGE_MIN, Z_PROBE_OFFSET_RANGE_MAX)) {
zprobe_zoffset = value;
SERIAL_ECHO(zprobe_zoffset);
}
else
SERIAL_ECHOPGM(MSG_Z_MIN " " STRINGIFY(Z_PROBE_OFFSET_RANGE_MIN) " " MSG_Z_MAX " " STRINGIFY(Z_PROBE_OFFSET_RANGE_MAX));
}
else
SERIAL_ECHOPAIR(": ", zprobe_zoffset);
SERIAL_EOL();
}
#endif // HAS_BED_PROBE