Source code for finesse.locks

"""Controlling an interferometer via error signals."""

import logging

from finesse.parameter import ParameterRef, bool_parameter, float_parameter
from finesse.element import ModelElement

LOGGER = logging.getLogger(__name__)


[docs]@float_parameter("gain", "Gain of the lock") @float_parameter("accuracy", "Accuracy to reach for the lock") @float_parameter("offset", "Offset applied to the input of the error signal") @bool_parameter("disabled", "Whether the lock is disabled or not") # IMPORTANT: renaming this class impacts the katscript spec and should be avoided! class Lock(ModelElement): """A simple lock which computes and applies the feedback to a given parameter using an error signal. Parameters ---------- name : str Name of newly created lock. error_signal : Any An error signal parameter or an object capable of producing a real-type error signal. This is typically a demodulated :class:`.PowerDetector` instance (or the name of the instance). feedback : :class:`.Parameter` A parameter of the model to apply the locks' feedback signal to. gain : float Control loop gain. accuracy : float Threshold to decide whether the loop is locked. disabled : boolean If true this lock will not run when the `RunLocks()` action is used. Explicitly specifying the name of the lock will override this setting, e.g. `RunLocks(name)`. offset : float An offset that is applied to the error signal before it is used. """ def __init__( self, name, error_signal, feedback, gain, accuracy, *, disabled=False, offset=0 ): super().__init__(name) self.__errsig = error_signal self.__feedback = feedback self.gain = gain self.accuracy = accuracy self.offset = offset self.disabled = disabled def _on_add(self, model): if isinstance(self.__errsig, str): self.__errsig = model.elements[self.__errsig] @property def error_signal(self): """The error signal of the lock.""" return self.__errsig @error_signal.setter def error_signal(self, value): self.__errsig = self._model.get_element(value) @property def feedback(self): """A handle to the parameter which the feedback signal is applied to.""" if isinstance(self.__feedback, ParameterRef): return self.__feedback.parameter else: return self.__feedback @feedback.setter def feedback(self, value): self.__feedback = value