# Printer stepper support # # Copyright (C) 2016,2017 Kevin O'Connor # # This file may be distributed under the terms of the GNU GPLv3 license. import math, logging import homing, pins # Code storing the definitions for a stepper motor class PrinterStepper: def __init__(self, printer, config): self.name = config.section if self.name.startswith('stepper_'): self.name = self.name[8:] self.need_motor_enable = True # Stepper definition self.mcu_stepper = pins.setup_pin( printer, 'stepper', config.get('step_pin')) dir_pin_params = pins.get_printer_pins(printer).parse_pin_desc( config.get('dir_pin'), can_invert=True) self.mcu_stepper.setup_dir_pin(dir_pin_params) self.step_dist = config.getfloat('step_distance', above=0.) self.mcu_stepper.setup_step_distance(self.step_dist) self.step_const = self.mcu_stepper.step_const self.step_delta = self.mcu_stepper.step_delta # Enable pin enable_pin = config.get('enable_pin', None) self.mcu_enable = None if enable_pin is not None: self.mcu_enable = pins.setup_pin(printer, 'digital_out', enable_pin) self.mcu_enable.setup_max_duration(0.) def _dist_to_time(self, dist, start_velocity, accel): # Calculate the time it takes to travel a distance with constant accel time_offset = start_velocity / accel return math.sqrt(2. * dist / accel + time_offset**2) - time_offset def set_max_jerk(self, max_halt_velocity, max_accel): # Calculate the firmware's maximum halt interval time last_step_time = self._dist_to_time( self.step_dist, max_halt_velocity, max_accel) second_last_step_time = self._dist_to_time( 2. * self.step_dist, max_halt_velocity, max_accel) min_stop_interval = second_last_step_time - last_step_time self.mcu_stepper.setup_min_stop_interval(min_stop_interval) def motor_enable(self, print_time, enable=0): if enable and self.need_motor_enable: self.mcu_stepper.reset_step_clock(print_time) if (self.mcu_enable is not None and self.mcu_enable.get_last_setting() != enable): self.mcu_enable.set_digital(print_time, enable) self.need_motor_enable = not enable # Support for stepper controlled linear axis with an endstop class PrinterHomingStepper(PrinterStepper): def __init__(self, printer, config): PrinterStepper.__init__(self, printer, config) # Endstop and its position self.mcu_endstop = pins.setup_pin( printer, 'endstop', config.get('endstop_pin')) self.mcu_endstop.add_stepper(self.mcu_stepper) self.position_endstop = config.getfloat('position_endstop') # Axis range self.position_min = config.getfloat('position_min', 0.) self.position_max = config.getfloat( 'position_max', 0., above=self.position_min) # Homing mechanics self.homing_speed = config.getfloat('homing_speed', 5.0, above=0.) self.homing_retract_dist = config.getfloat( 'homing_retract_dist', 5., above=0.) self.homing_positive_dir = config.getboolean('homing_positive_dir', None) if self.homing_positive_dir is None: axis_len = self.position_max - self.position_min if self.position_endstop <= self.position_min + axis_len / 4.: self.homing_positive_dir = False elif self.position_endstop >= self.position_max - axis_len / 4.: self.homing_positive_dir = True else: raise config.error( "Unable to infer homing_positive_dir in section '%s'" % ( config.section,)) # Endstop stepper phase position tracking self.homing_stepper_phases = config.getint( 'homing_stepper_phases', None, minval=0) endstop_accuracy = config.getfloat( 'homing_endstop_accuracy', None, above=0.) self.homing_endstop_accuracy = self.homing_endstop_phase = None if self.homing_stepper_phases: self.homing_endstop_phase = config.getint( 'homing_endstop_phase', None, minval=0 , maxval=self.homing_stepper_phases-1) if self.homing_endstop_phase is not None: # Adjust the endstop position so 0.0 is always at a full step micro_steps = self.homing_stepper_phases // 4 phase_offset = ( ((self.homing_endstop_phase + micro_steps // 2) % micro_steps) - micro_steps // 2) * self.step_dist full_step = micro_steps * self.step_dist es_pos = (int(self.position_endstop / full_step + .5) * full_step + phase_offset) if es_pos != self.position_endstop: logging.info("Changing %s endstop position to %.3f" " (from %.3f)", self.name, es_pos, self.position_endstop) self.position_endstop = es_pos if endstop_accuracy is None: self.homing_endstop_accuracy = self.homing_stepper_phases//2 - 1 elif self.homing_endstop_phase is not None: self.homing_endstop_accuracy = int(math.ceil( endstop_accuracy * .5 / self.step_dist)) else: self.homing_endstop_accuracy = int(math.ceil( endstop_accuracy / self.step_dist)) if self.homing_endstop_accuracy >= self.homing_stepper_phases // 2: logging.info("Endstop for %s is not accurate enough for stepper" " phase adjustment", name) self.homing_stepper_phases = None if self.mcu_endstop.get_mcu().is_fileoutput(): self.homing_endstop_accuracy = self.homing_stepper_phases def get_homing_speed(self): # Round the configured homing speed so that it is an even # number of ticks per step. adjusted_freq = self.mcu_stepper.get_mcu().get_adjusted_freq() dist_ticks = adjusted_freq * self.step_dist ticks_per_step = round(dist_ticks / self.homing_speed) return dist_ticks / ticks_per_step def get_homed_offset(self): if not self.homing_stepper_phases or self.need_motor_enable: return 0 pos = self.mcu_stepper.get_mcu_position() pos %= self.homing_stepper_phases if self.homing_endstop_phase is None: logging.info("Setting %s endstop phase to %d", self.name, pos) self.homing_endstop_phase = pos return 0 delta = (pos - self.homing_endstop_phase) % self.homing_stepper_phases if delta >= self.homing_stepper_phases - self.homing_endstop_accuracy: delta -= self.homing_stepper_phases elif delta > self.homing_endstop_accuracy: raise homing.EndstopError( "Endstop %s incorrect phase (got %d vs %d)" % ( self.name, pos, self.homing_endstop_phase)) return delta * self.step_dist