uniax, version 7.10.2021
- driving with a generator - 3 phases 1) find active range (low current, far movement until force over hysteresis) 2) release force until well below target 3) adjusting using pid_p. (this is in fact an integral factor)
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@ -22,94 +22,211 @@
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"""use transducer and motor to adjust force"""
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import time
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from secop.core import Drivable, Parameter, FloatRange, Done, Attached, Command
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from secop.lib import clamp
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from secop.core import Drivable, Parameter, FloatRange, EnumType, Done, \
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Attached, Command, PersistentMixin, PersistentParam, BoolType
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class Uniax(Drivable):
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class Uniax(PersistentMixin, Drivable):
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value = Parameter(unit='N')
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motor = Attached()
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transducer = Attached()
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step = Parameter('maximum motor step', FloatRange(unit='deg'), default=5, readonly=False)
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fine_step = Parameter('motor step for fine adjustment', FloatRange(unit='deg'), default=1, readonly=False)
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tolerance = Parameter('force tolerance', FloatRange(), readonly=False, default=1)
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tolerance = Parameter('force tolerance', FloatRange(), readonly=False, default=0.1)
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pid_p = PersistentParam('proportial term', FloatRange(unit='deg/N'), readonly=False, default=0.25, persistent='auto')
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filter_interval = Parameter('filter time', FloatRange(0, 60, unit='s'), readonly=False, default=1)
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span = Parameter('difference between max and min', FloatRange(), needscfg=False)
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current_sign = Parameter('', EnumType(negative=-1, undefined=0, positive=1), default=0)
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current_step = Parameter('', FloatRange(), default=0)
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force_offset = PersistentParam('transducer offset', FloatRange(), readonly=False, default=0, initwrite=True, persistent='auto')
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hysteresis = PersistentParam('force hysteresis', FloatRange(0), readonly=False, default=5, persistent='auto')
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release_step = PersistentParam('step when releasing force', FloatRange(0), readonly=False, default=20, persistent='auto')
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adjusting = Parameter('', BoolType(), readonly=False, default=False)
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adjusting_current = PersistentParam('current when adjusting force', FloatRange(0, 2.8, unit='A'), readonly=False, default=0.5, persistent='auto')
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adjusting_step = PersistentParam('max. motor step when adjusting force', FloatRange(0, unit='deg'), readonly=False, default=5, persistent='auto')
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safe_current = PersistentParam('current when moving far', FloatRange(0, 2.8, unit='A'), readonly=False, default=0.2, persistent='auto')
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low_pos = PersistentParam('max. position for positive forces', FloatRange(), readonly=False, default=0)
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high_pos = PersistentParam('min. position for negative forces', FloatRange(), readonly=False, default=0)
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pollinterval = 0.1
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fast_pollfactor = 1
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_target = None
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_mot_target = None
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_direction = 0
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_last_era = 0
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_driver = None # whe defined a gerenator to be called for driving
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_target = None # freshly set target
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_mot_target = None # for detecting manual motor manipulations
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_filter_start = 0
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_cnt = 0
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_sum = 0
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_min = None
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_max = None
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_last_min = None
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_last_max = None
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_cnt_rderr = 0
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_cnt_wrerr = 0
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def pos_range(self, target_sign, value=None):
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attr = 'high_pos' if target_sign > 0 else 'low_pos'
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if value is not None:
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value -= self.release_step * target_sign
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setattr(self, attr, value)
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return getattr(self, attr)
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def drive_to(self, pos):
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mot = self._motor
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self.current_step = pos - mot.value
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for itry in range(3):
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try:
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print('drive by %.2f' % self.current_step)
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self._mot_target = self._motor.write_target(pos)
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self._cnt_wrerr = max(0, self._cnt_wrerr - 1)
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break
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except Exception as e:
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print('driver_to', e)
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self._cnt_wrerr += 1
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if self._cnt_wrerr > 5:
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raise
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print('RESET')
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self._motor.reset()
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def drive_generator(self, target):
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self._mot_target = self._motor.target
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mot = self._motor
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target_sign = -1 if target < 0 else 1
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force = self.value
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# TODO: do this only when abs(target) > hysteresis?
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if target_sign != self.current_sign and force * target_sign < self.hysteresis:
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self.write_adjusting(False)
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pos_lim = None
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while target_sign * (target_sign * self.hysteresis - force) > self.tolerance:
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self.status = 'BUSY', 'find active motor range'
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# we have to increase abs(force)
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if not mot.isBusy() or target_sign * (mot.target - mot.value) < 0:
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self.drive_to(mot.value + 360 * target_sign)
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force = yield
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if target_sign * force < self.hysteresis:
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pos_lim = mot.value
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print('found active range')
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while mot.isBusy():
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mot.stop()
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force = yield
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print('stopped')
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if target_sign * (force - self.hysteresis) > 0:
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self.current_sign = target_sign
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elif pos_lim is not None:
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self.pos_range(target_sign, pos_lim)
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if abs(force) < self.hysteresis and self.low_pos < mot.value < self.high_pos:
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self.current_sign = 0
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if target_sign * (self.value - target) > self.tolerance:
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self.status = 'BUSY', 'release force'
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self.write_adjusting(True)
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# abs(force) too high
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while target_sign * (target - self.value) < self.hysteresis and self.value * target_sign > 0:
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self.drive_to(mot.value - target_sign * min(self.adjusting_step, self.release_step))
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while mot.isBusy():
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self.reset_filter()
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yield
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if target_sign * (force + self.hysteresis) < 0:
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print('force', force)
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self.terminate('ERROR', 'force too high when moving back')
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return
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print('released', self.value, target)
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self.write_adjusting(True)
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force = yield
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while target_sign * (target - self.value) > self.tolerance:
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self.status = 'BUSY', 'adjusting force'
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# slowly increasing abs(force)
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step = self.pid_p * (target - self.value)
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if abs(step) > self.adjusting_step:
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step = target_sign * self.adjusting_step
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self.drive_to(mot.value + step)
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while mot.isBusy():
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self.reset_filter()
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yield
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self.write_adjusting(False)
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self.status = 'IDLE', 'reached target'
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return
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def reset_filter(self, now=0):
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self._sum = self._cnt = 0
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self._filter_start = now or time.time()
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def read_value(self):
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force = self._transducer
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if self._target is not None:
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self._driver = self.drive_generator(self._target)
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self._driver.send(None) # start
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self._target = None
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mot = self._motor
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era = int(time.time() / self.filter_interval)
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newera = era != self._last_era
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value = force.read_value()
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if newera:
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self._last_era = era
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if self._min is None:
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self._min = self._max = self._last_max = self._last_min = value
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if self._cnt > 0:
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self.value = self._sum / self._cnt
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self._sum = self._cnt = 0
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self.span = self._max - self._min
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self._last_min = self._min
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self._last_max = self._max
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self._min = self._max = value
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self._min = min(self._min, value)
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self._max = max(self._max, value)
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try:
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value = self._transducer.read_value()
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self._cnt_rderr = max(0, self._cnt_rderr - 1)
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except Exception as e:
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self._cnt_rderr += 1
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if self._cnt_rderr > 10:
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self.terminate('ERROR', 'too many read errors: %s' % e)
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return Done
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now = time.time()
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newvalue = False
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if self._cnt > 0 and now > self._filter_start + self.filter_interval:
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self.value = self._sum / self._cnt
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self.reset_filter(now)
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newvalue = True
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self._sum += value
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self._cnt += 1
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high_value = max(self._max, self._last_max)
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low_value = min(self._min, self._last_min)
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if self._target is None:
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if mot.isBusy():
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self.status = self.Status.IDLE, 'stopping'
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else:
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self.status = self.Status.IDLE, ''
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return Done
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step = 0
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if self._direction > 0:
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if high_value < self._target - self.tolerance:
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step = self.step
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else:
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if low_value > self._target + self.tolerance:
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step = -self.step
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if not step:
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if self._direction * (self._target - value) < self.tolerance:
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self.stop()
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self.status = self.Status.IDLE, 'target reached'
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return Done
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if newera:
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step = self.fine_step * self._direction
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if step and not mot.isBusy():
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mot_target = mot.value + step
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self._mot_target = mot.write_target(mot_target)
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if self._driver:
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try:
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if self._mot_target != mot.target and mot.isBusy():
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print('mottarget', mot.target, self._mot_target)
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self.terminate('ERROR', 'stopped due to direct motor manipulation')
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return Done
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if self.adjusting:
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if newvalue:
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print(' %.2f' % self.value)
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# next step only when a new filtered value is available
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self._driver.send(self.value)
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else:
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print(' %.2f' % value)
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self._driver.send(value)
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except StopIteration:
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self._driver = None
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except Exception as e:
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self.terminate('ERROR', str(e))
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self._driver = None
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return Done
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def write_target(self, target):
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if abs(target - self.value) <= self.tolerance:
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if self.isBusy():
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self.stop()
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self.status = 'IDLE', 'already at target'
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return target
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self._cnt_rderr = 0
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self._cnt_wrerr = 0
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self.status = 'BUSY', 'changed target'
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self._target = target
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if target - self.value > 0:
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self._direction = 1
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else:
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self._direction = -1
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if self._motor.status[0] == self.Status.ERROR:
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self._motor.reset()
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self.status = self.Status.BUSY, 'changed target'
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self._mot_target = self._motor.target
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self.read_value()
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return target
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def terminate(self, *status):
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self.stop()
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self.status = status
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print(status)
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@Command()
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def stop(self):
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self._target = None
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self._motor.stop()
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self.status = self.Status.IDLE, 'stopped'
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self._driver = None
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if self._motor.isBusy():
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self._motor.stop()
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self.status = 'IDLE', 'stopped'
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self._filterd = True
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def write_force_offset(self, value):
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self.force_offset = value
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# self.saveParameters()
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self._transducer.write_offset(value)
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return Done
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def write_adjusting(self, value):
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mot = self._motor
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if value:
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mot_current = self.adjusting_current
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mot.write_move_limit(self.adjusting_step)
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else:
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mot_current = self.safe_current
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mot.write_safe_current(mot_current)
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if abs(mot_current - mot.maxcurrent) > 0.01: # resolution of current: 2.8 / 250
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mot.write_maxcurrent(mot_current)
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return value
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