SR844 RF Lock-in Amplifier

class QInstrument.instruments.StanfordResearch.SR844.instrument.QSR844(portName=None, **kwargs)

Bases: QSerialInstrument

SRS SR844 RF Lock-in Amplifier

Properties

Reference and Phase

frequencyfloat [Hz]

Reference frequency for the internal oscillator. Rounded to 5 significant digits or 0.0001 Hz, whichever is greater. Range: 25 MHz <= frequency <= 200 MHz

harmonicint

Detection harmonic. Range: 1 <= harmonic < 20000, frequency * harmonic <= 200 MHz

internal_referencebool

True: use internal reference source. False: use external reference source.

phasefloat [degrees]

Reference phase shift. Range: -360 <= phase <= 729.99

reference_impedanceint

Reference input impedance. 0: 50 Ohm, 1: 10 kOhm

Signal Input

input_impedanceint

Signal input impedance. 0: 50 Ohm, 1: 1 MOhm

wide_reserveint

Wide-band dynamic reserve mode. 0: high reserve, 1: normal, 2: low noise

Gain and Time Constant

close_reserveint

Close-in dynamic reserve mode. 0: high reserve, 1: normal, 2: low noise

low_pass_slopeint

0: 6 dB/octave, 1: 12 dB/octave, 2: 18 dB/octave, 3: 24 dB/octave

sensitivityint

0: 100 nVrms / -127 dBm 8: 1 mVrms / -47 dBm 1: 300 nVrms / -117 dBm 9: 3 mVrms / -37 dBm 2: 1 μVrms / -107 dBm 10: 10 mVrms / -27 dBm 3: 3 μVrms / -97 dBm 11: 30 mVrms / -17 dBm 4: 10 μVrms / -87 dBm 12: 100 mVrms / -7 dBm 5: 30 μVrms / -77 dBm 13: 300 mVrms / +3 dBm 6: 100 μVrms / -67 dBm 14: 1 Vrms / +13 dBm 7: 300 μVrms / -57 dBm

time_constantint

Input filter time constant. 0: 100 μs 9: 3 s 1: 300 μs 10: 10 s 2: 1 ms 11: 30 s 3: 3 ms 12: 100 s 4: 10 ms 13: 300 s 5: 30 ms 14: 1 ks 6: 100 ms 15: 3 ks 7: 300 ms 16: 10 ks 8: 1 s 17: 30 ks

comm = {'baudRate': qtpy.QtSerialPort.QSerialPort.BaudRate.Baud19200, 'dataBits': qtpy.QtSerialPort.QSerialPort.DataBits.Data8, 'eol': '\r', 'flowControl': qtpy.QtSerialPort.QSerialPort.FlowControl.NoFlowControl, 'parity': qtpy.QtSerialPort.QSerialPort.Parity.NoParity, 'stopBits': qtpy.QtSerialPort.QSerialPort.StopBits.OneStop}

identify()

Return True if the connected device identifies as an SR844.

Queries the instrument identification string (*IDN?) and checks for the 'SR844' model token in the response.

Return type:

bool

report()

Return the current frequency, magnitude, and phase simultaneously.

Uses the SNAP command for simultaneous capture, avoiding the timing errors that would result from three sequential queries.

Return type:

list[float]

Returns:

list[float] – [frequency [Hz], R [V], theta [degrees]]

reset()

Reset the SR844 to its factory default settings.

Return type:

None

auto_gain()

Automatically adjust the sensitivity (autorange gain).

Return type:

None

auto_close_reserve()

Automatically adjust the close-in dynamic reserve.

Return type:

None

auto_wide_reserve()

Automatically adjust the wide-band dynamic reserve.

Return type:

None

auto_phase()

Automatically adjust the reference phase.

Return type:

None

auto_offset_x()

Automatically offset the X output channel to zero.

Return type:

None

auto_offset_y()

Automatically offset the Y output channel to zero.

Return type:

None

auto_offset_r()

Automatically offset the R output channel to zero.

Return type:

None

auto_offset(channel)

Automatically offset the specified output channel to zero.

Parameters:

channel (int) – 1: X, 2: Y, 3: R

Return type:

None

class QInstrument.instruments.StanfordResearch.SR844.fake.QFakeSR844(*args, **kwargs)

Bases: QFakeInstrument, QSR844

Fake SR844 for UI development without hardware.

All read/write properties are backed by an in-memory store via the MRO auto-mock pattern.

identify()

Return True if the connected device identifies as an SR844.

Queries the instrument identification string (*IDN?) and checks for the 'SR844' model token in the response.

Return type:

bool

report()

Return simulated [frequency, R, theta].

Return type:

list[float]

class QInstrument.instruments.StanfordResearch.SR844.widget.QSR844Widget(*args: Any, **kwargs: Any)

Bases: QInstrumentWidget

Stanford Research Systems SR844 RF Lock-in Amplifier

UIFILE = 'SR844Widget.ui'

INSTRUMENT

alias of QSR844

class QInstrument.instruments.StanfordResearch.SR844.tree.QSR844Tree(*args, device=None, fields=None, **kwargs)

Bases: QInstrumentTree

Parameter tree for the Stanford Research Systems SR844 RF Lock-in Amplifier.

INSTRUMENT

alias of QSR844