from typing import Optional, Union
from qcodes.instrument import Instrument
from qcodes.parameters import Parameter
[docs]class VoltageDivider(Parameter):
"""
Resitive voltage divider
To be used when you use a physical voltage divider to set or get a voltage.
Initialize the voltage diveder by passing the parameter to be measured
and the value of the division (which should be calibrated beforehand)
>>> vd = VoltageDivider(dac.chan0, 10)
The voltage divider acts a your original parameter, but will set the right
value, and store the division_value in the metadata.
Set the value you want to set your device at 10 V
>>> vd(10)
This will set the dac.cha0 at 10*10, but upon measuring the divider
the value returned is the voltage at the sample.
>>> vd()
10
To get the voltage that was actually set on the instrument:
>>> vd.get_instrument_value()
100
Args:
v1: Parameter physically attached to the divider as input
division_value: the divsion value of the divider
label: label of this parameter, by default uses v1 label
but attaches _attenuated
name: name of this parameter, by default uses v1 name
but attaches _attenuated
"""
def __init__(self,
v1: Parameter,
division_value: Union[int, float],
name: Optional[str] = None,
label: Optional[str] = None,
instrument: Union[None, Instrument] = None) -> None:
self.v1 = v1
self.division_value = division_value
if label:
self.label = label
else:
self.label = f"{self.v1.label}_attenuated"
if not name:
name = f"{self.v1.name}_attenuated"
if not instrument:
instrument = getattr(self.v1, "_instrument", None)
super().__init__(
name=name,
instrument=instrument,
label=self.label,
unit=self.v1.unit,
metadata=self.v1.metadata)
# extend metadata
self._meta_attrs.extend(["division_value"])
[docs] def set_raw(self, value: Union[int, float]) -> None:
instrument_value = value * self.division_value
self.v1.set(instrument_value)
[docs] def get_raw(self) -> Union[int, float]:
"""
Returns:
value at which was set at the sample
"""
value = self.v1.get() / self.division_value
return value
[docs] def get_instrument_value(self) -> Union[int, float]:
"""
Returns:
value at which the attached parameter is (i.e. does
not account for the scaling)
"""
return self.v1.get()