from typing import Any, Optional
from qcodes.instrument import Instrument
from qcodes.parameters import MultiParameter, Parameter, ParamRawDataType
from qcodes.validators import Bool, Enum
class VoltageParameter(MultiParameter):
"""
Amplified voltage measurement via an SR560 preamp and a measured voltage.
To be used when you feed a voltage into an SR560, send the SR560's
output voltage to a lockin or other voltage amplifier, and you have
the voltage reading from that amplifier as a qcodes parameter.
``VoltageParameter.get()`` returns ``(voltage_raw, voltage)``
Args:
measured_param: a gettable parameter returning the
voltage read from the SR560 output.
v_amp_ins: an SR560 instance where you manually
maintain the present settings of the real SR560 amp.
Note: it should be possible to use other voltage preamps, if they
define parameters ``gain`` (V_out / V_in) and ``invert``
(bool, output is inverted)
name: the name of the current output. Default 'volt'.
Also used as the name of the whole parameter.
"""
def __init__(self,
measured_param: Parameter,
v_amp_ins: "SR560",
name: str = 'volt',
snapshot_value: bool = True):
p_name = measured_param.name
super().__init__(name=name,
names=(p_name+'_raw', name),
shapes=((), ()),
instrument=v_amp_ins)
self._measured_param = measured_param
p_label = getattr(measured_param, "label", "")
p_unit = getattr(measured_param, "unit", "")
self.labels = (p_label, 'Voltage')
self.units = (p_unit, 'V')
def get_raw(self) -> tuple[ParamRawDataType, ParamRawDataType]:
volt = self._measured_param.get()
assert isinstance(self.instrument, SR560)
volt_amp = volt / self.instrument.gain.get()
if self.instrument.invert.get():
volt_amp *= -1
value = (volt, volt_amp)
return value
[docs]
class SR560(Instrument):
"""
QCoDeS driver for the Stanford Research Systems SR560 Voltage-preamplifier.
This is a virtual driver only and will not talk to your instrument.
Note:
- The ``cutoff_lo`` and ``cutoff_hi`` parameters will interact with
each other on the instrument (hi cannot be <= lo) but this is not
managed here, you must ensure yourself that both are correct whenever
you change one of them.
- ``gain`` has a vernier setting, which does not yield a well-defined
output. We restrict this driver to only the predefined gain values.
"""
def __init__(self, name: str, **kwargs: Any):
super().__init__(name, **kwargs)
cutoffs = ['DC', 0.03, 0.1, 0.3, 1, 3, 10, 30, 100, 300, 1000,
3000, 10000, 30000, 100000, 300000, 1000000]
gains = [1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000,
10000, 20000, 50000]
self.add_parameter('cutoff_lo',
get_cmd=None, set_cmd=None,
initial_value='DC',
label='High pass',
unit='Hz',
vals=Enum(*cutoffs))
self.add_parameter('cutoff_hi',
get_cmd=None, set_cmd=None,
initial_value=1e6,
label='Low pass',
unit='Hz',
vals=Enum(*cutoffs))
self.add_parameter('invert',
get_cmd=None, set_cmd=None,
initial_value=True,
label='Inverted output',
vals=Bool())
self.add_parameter('gain',
get_cmd=None, set_cmd=None,
initial_value=10,
label='Gain',
unit=None,
vals=Enum(*gains))
[docs]
def get_idn(self) -> dict[str, Optional[str]]:
vendor = 'Stanford Research Systems'
model = 'SR560'
serial = None
firmware = None
return {'vendor': vendor, 'model': model,
'serial': serial, 'firmware': firmware}