"""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