src/modules/tools/zprobe/ZProbe.cpp

   1 /*
   2       This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl).
   3       Smoothie 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.
   4       Smoothie 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.
   5       You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>.
   6 */
   7
   8 #include "ZProbe.h"
   9
  10 #include "Kernel.h"
  11 #include "BaseSolution.h"
  12 #include "Config.h"
  13 #include "Robot.h"
  14 #include "StepperMotor.h"
  15 #include "StreamOutputPool.h"
  16 #include "Gcode.h"
  17 #include "Conveyor.h"
  18 #include "Stepper.h"
  19 #include "checksumm.h"
  20 #include "ConfigValue.h"
  21 #include "SlowTicker.h"
  22 #include "Planner.h"
  23 #include "SerialMessage.h"
  24 #include "PublicDataRequest.h"
  25 #include "EndstopsPublicAccess.h"
  26 #include "PublicData.h"
  27 #include "LevelingStrategy.h"
  28 #include "StepTicker.h"
  29 #include "utils.h"
  30
  31 // strategies we know about
  32 #include "DeltaCalibrationStrategy.h"
  33 #include "ThreePointStrategy.h"
  34 #include "ZGridStrategy.h"
  35
  36 #define enable_checksum          CHECKSUM("enable")
  37 #define probe_pin_checksum       CHECKSUM("probe_pin")
  38 #define debounce_count_checksum  CHECKSUM("debounce_count")
  39 #define slow_feedrate_checksum   CHECKSUM("slow_feedrate")
  40 #define fast_feedrate_checksum   CHECKSUM("fast_feedrate")
  41 #define return_feedrate_checksum CHECKSUM("return_feedrate")
  42 #define probe_height_checksum    CHECKSUM("probe_height")
  43 #define gamma_max_checksum       CHECKSUM("gamma_max")
  44
  45 // from endstop section
  46 #define delta_homing_checksum    CHECKSUM("delta_homing")
  47
  48 #define X_AXIS 0
  49 #define Y_AXIS 1
  50 #define Z_AXIS 2
  51
  52 #define STEPPER THEKERNEL->robot->actuators
  53 #define STEPS_PER_MM(a) (STEPPER[a]->get_steps_per_mm())
  54 #define Z_STEPS_PER_MM STEPS_PER_MM(Z_AXIS)
  55
  56 #define abs(a) ((a<0) ? -a : a)
  57
  58 void ZProbe::on_module_loaded()
  59 {
  60     // if the module is disabled -> do nothing
  61     if(!THEKERNEL->config->value( zprobe_checksum, enable_checksum )->by_default(false)->as_bool()) {
  62         // as this module is not needed free up the resource
  63         delete this;
  64         return;
  65     }
  66     this->running = false;
  67
  68     // load settings
  69     this->on_config_reload(this);
  70     // register event-handlers
  71     register_for_event(ON_GCODE_RECEIVED);
  72
  73     THEKERNEL->step_ticker->register_acceleration_tick_handler([this](){acceleration_tick(); });
  74 }
  75
  76 void ZProbe::on_config_reload(void *argument)
  77 {
  78     this->pin.from_string( THEKERNEL->config->value(zprobe_checksum, probe_pin_checksum)->by_default("nc" )->as_string())->as_input();
  79     this->debounce_count = THEKERNEL->config->value(zprobe_checksum, debounce_count_checksum)->by_default(0  )->as_number();
  80
  81     // get strategies to load
  82     vector<uint16_t> modules;
  83     THEKERNEL->config->get_module_list( &modules, leveling_strategy_checksum);
  84     for( auto cs : modules ){
  85         if( THEKERNEL->config->value(leveling_strategy_checksum, cs, enable_checksum )->as_bool() ){
  86             bool found= false;
  87             // check with each known strategy and load it if it matches
  88             switch(cs) {
  89                 case delta_calibration_strategy_checksum:
  90                     this->strategies.push_back(new DeltaCalibrationStrategy(this));
  91                     found= true;
  92                     break;
  93
  94                 case three_point_leveling_strategy_checksum:
  95                     // NOTE this strategy is mutually exclusive with the delta calibration strategy
  96                     this->strategies.push_back(new ThreePointStrategy(this));
  97                     found= true;
  98                     break;
  99
 100                 case ZGrid_leveling_checksum:
 101                      this->strategies.push_back(new ZGridStrategy(this));
 102                      found= true;
 103                      break;
 104
 105                 // add other strategies here
 106                 //case zheight_map_strategy:
 107                 //     this->strategies.push_back(new ZHeightMapStrategy(this));
 108                 //     found= true;
 109                 //     break;
 110             }
 111             if(found) this->strategies.back()->handleConfig();
 112         }
 113     }
 114
 115     // need to know if we need to use delta kinematics for homing
 116     this->is_delta = THEKERNEL->config->value(delta_homing_checksum)->by_default(false)->as_bool();
 117
 118     // default for backwards compatibility add DeltaCalibrationStrategy if a delta
 119     // will be deprecated
 120     if(this->strategies.empty()) {
 121         if(this->is_delta) {
 122             this->strategies.push_back(new DeltaCalibrationStrategy(this));
 123             this->strategies.back()->handleConfig();
 124         }
 125     }
 126
 127     this->probe_height  = THEKERNEL->config->value(zprobe_checksum, probe_height_checksum)->by_default(5.0F)->as_number();
 128     this->slow_feedrate = THEKERNEL->config->value(zprobe_checksum, slow_feedrate_checksum)->by_default(5)->as_number(); // feedrate in mm/sec
 129     this->fast_feedrate = THEKERNEL->config->value(zprobe_checksum, fast_feedrate_checksum)->by_default(100)->as_number(); // feedrate in mm/sec
 130     this->return_feedrate = THEKERNEL->config->value(zprobe_checksum, return_feedrate_checksum)->by_default(0)->as_number(); // feedrate in mm/sec
 131     this->max_z         = THEKERNEL->config->value(gamma_max_checksum)->by_default(500)->as_number(); // maximum zprobe distance
 132 }
 133
 134 bool ZProbe::wait_for_probe(int& steps)
 135 {
 136     unsigned int debounce = 0;
 137     while(true) {
 138         THEKERNEL->call_event(ON_IDLE);
 139         if(THEKERNEL->is_halted()){
 140             // aborted by kill
 141             return false;
 142         }
 143
 144         // if no stepper is moving, moves are finished and there was no touch
 145         if( !STEPPER[Z_AXIS]->is_moving() && (!is_delta || (!STEPPER[Y_AXIS]->is_moving() && !STEPPER[Z_AXIS]->is_moving())) ) {
 146             return false;
 147         }
 148
 149         // if the touchprobe is active...
 150         if( this->pin.get() ) {
 151             //...increase debounce counter...
 152             if( debounce < debounce_count) {
 153                 // ...but only if the counter hasn't reached the max. value
 154                 debounce++;
 155             } else {
 156                 // ...otherwise stop the steppers, return its remaining steps
 157                 if(STEPPER[Z_AXIS]->is_moving()){
 158                     steps= STEPPER[Z_AXIS]->get_stepped();
 159                     STEPPER[Z_AXIS]->move(0, 0);
 160                 }
 161                 if(is_delta) {
 162                     for( int i = X_AXIS; i <= Y_AXIS; i++ ) {
 163                         if ( STEPPER[i]->is_moving() ) {
 164                             STEPPER[i]->move(0, 0);
 165                         }
 166                     }
 167                 }
 168                 return true;
 169             }
 170         } else {
 171             // The probe was not hit yet, reset debounce counter
 172             debounce = 0;
 173         }
 174     }
 175 }
 176
 177 // single probe with custom feedrate
 178 // returns boolean value indicating if probe was triggered
 179 bool ZProbe::run_probe_feed(int& steps, float feedrate, float max_dist)
 180 {
 181     // not a block move so disable the last tick setting
 182     for ( int c = X_AXIS; c <= Z_AXIS; c++ ) {
 183         STEPPER[c]->set_moved_last_block(false);
 184     }
 185
 186     // Enable the motors
 187     THEKERNEL->stepper->turn_enable_pins_on();
 188     this->current_feedrate = feedrate * Z_STEPS_PER_MM; // steps/sec
 189     float maxz= max_dist < 0 ? this->max_z*2 : max_dist;
 190
 191     // move Z down
 192     STEPPER[Z_AXIS]->move(true, maxz * Z_STEPS_PER_MM, 0); // always probes down, no more than 2*maxz
 193     if(this->is_delta) {
 194         // for delta need to move all three actuators
 195         STEPPER[X_AXIS]->move(true, maxz * STEPS_PER_MM(X_AXIS), 0);
 196         STEPPER[Y_AXIS]->move(true, maxz * STEPS_PER_MM(Y_AXIS), 0);
 197     }
 198
 199     // start acceleration processing
 200     this->running = true;
 201
 202     bool r = wait_for_probe(steps);
 203     this->running = false;
 204     STEPPER[X_AXIS]->move(0, 0);
 205     STEPPER[Y_AXIS]->move(0, 0);
 206     STEPPER[Z_AXIS]->move(0, 0);
 207     return r;
 208 }
 209
 210 // single probe with either fast or slow feedrate
 211 // returns boolean value indicating if probe was triggered
 212 bool ZProbe::run_probe(int& steps, bool fast)
 213 {
 214     float feedrate = (fast ? this->fast_feedrate : this->slow_feedrate);
 215     return run_probe_feed(steps, feedrate);
 216
 217 }
 218
 219 bool ZProbe::return_probe(int steps)
 220 {
 221     // move probe back to where it was
 222
 223     float fr;
 224     if(this->return_feedrate != 0) { // use return_feedrate if set
 225         fr = this->return_feedrate;
 226     } else {
 227         fr = this->slow_feedrate*2; // nominally twice slow feedrate
 228         if(fr > this->fast_feedrate) fr = this->fast_feedrate; // unless that is greater than fast feedrate
 229     }
 230
 231     this->current_feedrate = fr * Z_STEPS_PER_MM; // feedrate in steps/sec
 232     bool dir= steps < 0;
 233     steps= abs(steps);
 234
 235     STEPPER[Z_AXIS]->move(dir, steps, 0);
 236     if(this->is_delta) {
 237         STEPPER[X_AXIS]->move(dir, steps, 0);
 238         STEPPER[Y_AXIS]->move(dir, steps, 0);
 239     }
 240
 241     this->running = true;
 242     while(STEPPER[Z_AXIS]->is_moving() || (is_delta && (STEPPER[X_AXIS]->is_moving() || STEPPER[Y_AXIS]->is_moving())) ) {
 243         // wait for it to complete
 244         THEKERNEL->call_event(ON_IDLE);
 245          if(THEKERNEL->is_halted()){
 246             // aborted by kill
 247             break;
 248         }
 249     }
 250
 251     this->running = false;
 252     STEPPER[X_AXIS]->move(0, 0);
 253     STEPPER[Y_AXIS]->move(0, 0);
 254     STEPPER[Z_AXIS]->move(0, 0);
 255
 256     return true;
 257 }
 258
 259 bool ZProbe::doProbeAt(int &steps, float x, float y)
 260 {
 261     int s;
 262     // move to xy
 263     coordinated_move(x, y, NAN, getFastFeedrate());
 264     if(!run_probe(s)) return false;
 265
 266     // return to original Z
 267     return_probe(s);
 268     steps = s;
 269
 270     return true;
 271 }
 272
 273 float ZProbe::probeDistance(float x, float y)
 274 {
 275     int s;
 276     if(!doProbeAt(s, x, y)) return NAN;
 277     return zsteps_to_mm(s);
 278 }
 279
 280 void ZProbe::on_gcode_received(void *argument)
 281 {
 282     Gcode *gcode = static_cast<Gcode *>(argument);
 283
 284     if( gcode->has_g && gcode->g >= 29 && gcode->g <= 32) {
 285
 286         // make sure the probe is defined and not already triggered before moving motors
 287         if(!this->pin.connected()) {
 288             gcode->stream->printf("ZProbe not connected.\n");
 289             return;
 290         }
 291         if(this->pin.get()) {
 292             gcode->stream->printf("ZProbe triggered before move, aborting command.\n");
 293             return;
 294         }
 295
 296         if( gcode->g == 30 ) { // simple Z probe
 297             // first wait for an empty queue i.e. no moves left
 298             THEKERNEL->conveyor->wait_for_empty_queue();
 299
 300             int steps;
 301             bool probe_result;
 302             if(gcode->has_letter('F')) {
 303                 probe_result = run_probe_feed(steps, gcode->get_value('F') / 60);
 304             } else {
 305                 probe_result = run_probe(steps);
 306             }
 307
 308             if(probe_result) {
 309                 gcode->stream->printf("Z:%1.4f C:%d\n", zsteps_to_mm(steps), steps);
 310                 // move back to where it started, unless a Z is specified
 311                 if(gcode->has_letter('Z')) {
 312                     // set Z to the specified value, and leave probe where it is
 313                     THEKERNEL->robot->reset_axis_position(gcode->get_value('Z'), Z_AXIS);
 314                 } else {
 315                     return_probe(steps);
 316                 }
 317             } else {
 318                 gcode->stream->printf("ZProbe not triggered\n");
 319             }
 320
 321         } else {
 322             if(!gcode->has_letter('P')) {
 323                 // find the first strategy to handle the gcode
 324                 for(auto s : strategies){
 325                     if(s->handleGcode(gcode)) {
 326                         return;
 327                     }
 328                 }
 329                 gcode->stream->printf("No strategy found to handle G%d\n", gcode->g);
 330
 331             }else{
 332                 // P paramater selects which strategy to send the code to
 333                 // they are loaded in the order they are defined in config, 0 being the first, 1 being the second and so on.
 334                 uint16_t i= gcode->get_value('P');
 335                 if(i < strategies.size()) {
 336                     if(!strategies[i]->handleGcode(gcode)){
 337                         gcode->stream->printf("strategy #%d did not handle G%d\n", i, gcode->g);
 338                     }
 339                     return;
 340
 341                 }else{
 342                     gcode->stream->printf("strategy #%d is not loaded\n", i);
 343                 }
 344             }
 345         }
 346
 347     } else if(gcode->has_g && gcode->g == 38 ) { // G38.2 Straight Probe with error, G38.3 straight probe without error
 348         // linuxcnc/grbl style probe http://www.linuxcnc.org/docs/2.5/html/gcode/gcode.html#sec:G38-probe
 349         if(gcode->subcode != 2 && gcode->subcode != 3) {
 350             gcode->stream->printf("error:Only G38.2 and G38.3 are supported\n");
 351             return;
 352         }
 353
 354         // make sure the probe is defined and not already triggered before moving motors
 355         if(!this->pin.connected()) {
 356             gcode->stream->printf("error:ZProbe not connected.\n");
 357             return;
 358         }
 359         if(this->pin.get()) {
 360             gcode->stream->printf("error:ZProbe triggered before move, aborting command.\n");
 361             return;
 362         }
 363
 364         // first wait for an empty queue i.e. no moves left
 365         THEKERNEL->conveyor->wait_for_empty_queue();
 366
 367         if(gcode->has_letter('X')) {
 368             // probe in the X axis
 369             probe_XY(gcode, X_AXIS);
 370
 371         }else if(gcode->has_letter('Y')) {
 372             // probe in the Y axis
 373             probe_XY(gcode, Y_AXIS);
 374
 375         }else if(gcode->has_letter('Z')) {
 376             // we need to know where we started the probe from
 377             float current_machine_pos[3];
 378             THEKERNEL->robot->get_axis_position(current_machine_pos);
 379
 380             // probe down in the Z axis no more than the Z value in mm
 381             float rate = (gcode->has_letter('F')) ? gcode->get_value('F') / 60 : this->slow_feedrate;
 382             int steps;
 383             bool probe_result = run_probe_feed(steps, rate, gcode->get_value('Z'));
 384
 385             if(probe_result) {
 386                 float z= current_machine_pos[Z_AXIS] - zsteps_to_mm(steps);
 387                 if(THEKERNEL->is_grbl_mode()) {
 388                     gcode->stream->printf("[PRB:%1.3f,%1.3f,%1.3f:1]\n", current_machine_pos[X_AXIS], current_machine_pos[Y_AXIS], z);
 389
 390                 }else{
 391                     gcode->stream->printf("INFO: delta Z %1.4f (Steps %d)\n", steps / Z_STEPS_PER_MM, steps);
 392                 }
 393
 394                 // set position to where it stopped
 395                 THEKERNEL->robot->reset_axis_position(z, Z_AXIS);
 396
 397             } else {
 398                 if(THEKERNEL->is_grbl_mode()) {
 399                     if(gcode->subcode == 2) {
 400                         gcode->stream->printf("ALARM:Probe fail\n");
 401                         THEKERNEL->call_event(ON_HALT, nullptr);
 402                     }
 403                     gcode->stream->printf("[PRB:%1.3f,%1.3f,%1.3f:0]\n", current_machine_pos[X_AXIS], current_machine_pos[Y_AXIS], current_machine_pos[Z_AXIS]);
 404
 405                 }else{
 406                     gcode->stream->printf("error:ZProbe not triggered\n");
 407                 }
 408             }
 409
 410         }else{
 411             gcode->stream->printf("error:at least one of X Y or Z must be specified\n");
 412
 413         }
 414         return;
 415
 416     } else if(gcode->has_m) {
 417         // M code processing here
 418         int c;
 419         switch (gcode->m) {
 420             case 119:
 421                 c = this->pin.get();
 422                 gcode->stream->printf(" Probe: %d", c);
 423                 gcode->add_nl = true;
 424                 break;
 425
 426             case 670:
 427                 if (gcode->has_letter('S')) this->slow_feedrate = gcode->get_value('S');
 428                 if (gcode->has_letter('K')) this->fast_feedrate = gcode->get_value('K');
 429                 if (gcode->has_letter('R')) this->return_feedrate = gcode->get_value('R');
 430                 if (gcode->has_letter('Z')) this->max_z = gcode->get_value('Z');
 431                 if (gcode->has_letter('H')) this->probe_height = gcode->get_value('H');
 432                 break;
 433
 434             case 500: // save settings
 435             case 503: // print settings
 436                 gcode->stream->printf(";Probe feedrates Slow/fast(K)/Return (mm/sec) max_z (mm) height (mm):\nM670 S%1.2f K%1.2f R%1.2f Z%1.2f H%1.2f\n",
 437                     this->slow_feedrate, this->fast_feedrate, this->return_feedrate, this->max_z, this->probe_height);
 438
 439                 // fall through is intended so leveling strategies can handle m-codes too
 440
 441             default:
 442                 for(auto s : strategies){
 443                     if(s->handleGcode(gcode)) {
 444                         return;
 445                     }
 446                 }
 447         }
 448     }
 449 }
 450
 451 // special way to probe in the X or Y direction
 452 void ZProbe::probe_XY(Gcode *gcode, int axis)
 453 {
 454     // enable the probe checking in the stepticker
 455     THEKERNEL->step_ticker->probe_fnc= [this]() { return this->pin.get(); };
 456
 457     // get probe feedrate if specified
 458     float rate = (gcode->has_letter('F')) ? gcode->get_value('F')*60 : this->slow_feedrate;
 459
 460      // do a regular move which will stop as soon as the probe is triggered, or the distance is reached
 461     if(axis == X_AXIS) {
 462         coordinated_move(gcode->get_value('X'), 0, 0, rate, true);
 463
 464     }else if(axis == Y_AXIS) {
 465         coordinated_move(0, gcode->get_value('Y'), 0, rate, true);
 466
 467     }else{
 468         // this is an error
 469         THEKERNEL->step_ticker->probe_fnc= nullptr;
 470         return;
 471     }
 472
 473     // now wait for the move to finish
 474     THEKERNEL->conveyor->wait_for_empty_queue();
 475
 476     float pos[3];
 477     {
 478         // get the current position
 479         ActuatorCoordinates current_position{
 480             THEKERNEL->robot->actuators[X_AXIS]->get_current_position(),
 481             THEKERNEL->robot->actuators[Y_AXIS]->get_current_position(),
 482             THEKERNEL->robot->actuators[Z_AXIS]->get_current_position()
 483         };
 484
 485         // get machine position from the actuator position using FK
 486         THEKERNEL->robot->arm_solution->actuator_to_cartesian(current_position, pos);
 487     }
 488
 489     // see if probe was triggered
 490     // handle debounce here, 200ms should be enough
 491     safe_delay(200);
 492     int probeok= this->pin.get() ? 1 : 0;
 493     if(gcode->subcode == 2) {
 494         // issue error if probe was not triggered and subcode == 2
 495         gcode->stream->printf("ALARM:Probe fail\n");
 496         THEKERNEL->call_event(ON_HALT, nullptr);
 497     }
 498
 499     gcode->stream->printf("[PRB:%1.3f,%1.3f,%1.3f:%d]\n", pos[X_AXIS], pos[Y_AXIS], pos[Z_AXIS], probeok);
 500
 501     // disable probe checking
 502     THEKERNEL->step_ticker->probe_fnc= nullptr;
 503 }
 504
 505 // Called periodically to change the speed to match acceleration
 506 void ZProbe::acceleration_tick(void)
 507 {
 508     if(!this->running) return; // nothing to do
 509     if(STEPPER[Z_AXIS]->is_moving()) accelerate(Z_AXIS);
 510
 511     if(is_delta) {
 512          // deltas needs to move all actuators
 513         for ( int c = X_AXIS; c <= Y_AXIS; c++ ) {
 514             if( !STEPPER[c]->is_moving() ) continue;
 515             accelerate(c);
 516         }
 517     }
 518
 519     return;
 520 }
 521
 522 void ZProbe::accelerate(int c)
 523 {   uint32_t current_rate = STEPPER[c]->get_steps_per_second();
 524     uint32_t target_rate = floorf(this->current_feedrate);
 525
 526     // Z may have a different acceleration to X and Y
 527     float acc= (c==Z_AXIS) ? THEKERNEL->planner->get_z_acceleration() : THEKERNEL->planner->get_acceleration();
 528     if( current_rate < target_rate ) {
 529         uint32_t rate_increase = floorf((acc / THEKERNEL->acceleration_ticks_per_second) * STEPS_PER_MM(c));
 530         current_rate = min( target_rate, current_rate + rate_increase );
 531     }
 532     if( current_rate > target_rate ) {
 533         current_rate = target_rate;
 534     }
 535
 536     // steps per second
 537     STEPPER[c]->set_speed(current_rate);
 538 }
 539
 540 // issue a coordinated move directly to robot, and return when done
 541 // Only move the coordinates that are passed in as not nan
 542 // NOTE must use G53 to force move in machine coordiantes and ignore any WCS offsetts
 543 void ZProbe::coordinated_move(float x, float y, float z, float feedrate, bool relative)
 544 {
 545     char buf[32];
 546     char cmd[64];
 547
 548     if(relative) strcpy(cmd, "G91 G0 ");
 549     else strcpy(cmd, "G53 G0 "); // G53 forces movement in machine coordinate system
 550
 551     if(!isnan(x)) {
 552         int n = snprintf(buf, sizeof(buf), " X%1.3f", x);
 553         strncat(cmd, buf, n);
 554     }
 555     if(!isnan(y)) {
 556         int n = snprintf(buf, sizeof(buf), " Y%1.3f", y);
 557         strncat(cmd, buf, n);
 558     }
 559     if(!isnan(z)) {
 560         int n = snprintf(buf, sizeof(buf), " Z%1.3f", z);
 561         strncat(cmd, buf, n);
 562     }
 563
 564     // use specified feedrate (mm/sec)
 565     int n = snprintf(buf, sizeof(buf), " F%1.1f", feedrate * 60); // feed rate is converted to mm/min
 566     strncat(cmd, buf, n);
 567     if(relative) strcat(cmd, " G90");
 568
 569     //THEKERNEL->streams->printf("DEBUG: move: %s\n", cmd);
 570
 571     // send as a command line as may have multiple G codes in it
 572     struct SerialMessage message;
 573     message.message = cmd;
 574     message.stream = &(StreamOutput::NullStream);
 575     THEKERNEL->call_event(ON_CONSOLE_LINE_RECEIVED, &message );
 576     THEKERNEL->conveyor->wait_for_empty_queue();
 577 }
 578
 579 // issue home command
 580 void ZProbe::home()
 581 {
 582     Gcode gc("G28", &(StreamOutput::NullStream));
 583     THEKERNEL->call_event(ON_GCODE_RECEIVED, &gc);
 584 }
 585
 586 float ZProbe::zsteps_to_mm(float steps)
 587 {
 588     return steps / Z_STEPS_PER_MM;
 589 }