Defining a station

In this example we will shortly discuss the use of a station with instruments. A station bounds instruments and has functionality to control and store the settings of the devices. We will start from a simulated station (the virtual dot array) that has a special function initialize to directly create the station object with simulated instruments:

from qtt.simulation import virtual_dot_array
station = virtual_dot_array.initialize()

initialize: create virtualdot
initialized virtual dot system (2 dots)

The simulated station contain the instuments; gates, keithley1, keithley3, keithley4, ivvi1, ivvi2, vawg and a digitizer. In general, every Instrument of a station have Parameter items, which are gettable or settable. For example, using the simulated station we can get the keithley and P1 gate amplitude:

gates = station.gates
print(gates)
print(gates.P1.get())

gates.P1.set(1.5)
print(gates.P1.get())

keithley1 = station.keithley1
print(keithley1)
print(keithley1.amplitude.get())

gates: gates (16 gates)
0.3166101322411219
1.5
<VirtualMeter: keithley1>
2.9964151248162425

Default workflow after connecting the instruments (the initialize function) is to use the station with the measurement functions. The measurements make use of the instruments in the station. To create a station, you need to define you own initialize function. An example initialize function is shown below. For your own setup to have to modify the code with the correct instruments and settings.

from qtt.instrument_drivers.gates import VirtualDAC

# the gate_map defines the relation between names gates and the DAC channels of physical instruments
gate_map = {'P0': (0,1), 'P1', (0,2), 'P3', (0,3), 'B0', (1,0), 'B1': (1,1), 'B2': (1,2), 'B3': (1,3)}

def initialize():

    logging.info('my station: initialize')

    # Loading IVVI
    logging.info('my station: load IVVI driver')
    ivvi1 = IVVI.IVVI(name='ivvi1', address='COM5', numdacs=16,)
    ivvi2 = IVVI.IVVI(name='ivvi2', address='COM6', numdacs=16,)

    # Loading Lockins
    logging.info('my station: load lockin driver')
    lockin1 = SR830.SR830(name='lockin1', address='GPIB1::6::INSTR')
    lockin1.output_interface('GPIB')

    # Loading digitizer
    logging.info('my station: load digitizer driver')
    digitizer = M4i.M4i(name='digitizer')

    logging.info('my station: all drivers have been loaded')

    # Create virtual instruments
    gates = VirtualDAC(name='gates', gate_map=gate_map, instruments=[ivvi1, ivvi2])

    #Creating the experimental station
    station = qcodes.Station(ivvi1, ivvi2,, lockin1, digitizer, gates)

    logging.info('my station: initialization done')
    return station

A view of all the settings of a instrument or station can be shown using the snapshot function. The measurements use snapshot to collect the settings, which are stored together with the measurement results.

print(keithley1.snapshot())

{'functions': {}, 'submodules': {}, '__class__': 'qtt.instrument_drivers.virtual_instruments.VirtualMeter', 'parameters': {'IDN': {'value': None, 'ts': None, 'raw_value': None, '__class__': 'qcodes.instrument.parameter.Parameter', 'full_name': 'keithley1_IDN', 'unit': '', 'instrument': 'qtt.instrument_drivers.virtual_instruments.VirtualMeter', 'instrument_name': 'keithley1', 'label': 'IDN', 'inter_delay': 0, 'name': 'IDN', 'vals': '<Anything>', 'post_delay': 0}, 'amplitude': {'value': 2.9964151248162425, 'ts': '2018-09-16 21:34:35', 'raw_value': 2.9964151248162425, '__class__': 'qcodes.instrument.parameter.Parameter', 'full_name': 'keithley1_amplitude', 'unit': 'a.u.', 'instrument': 'qtt.instrument_drivers.virtual_instruments.VirtualMeter', 'instrument_name': 'keithley1', 'label': 'keithley1 amplitude', 'inter_delay': 0, 'name': 'amplitude', 'post_delay': 0}, 'readnext': {'value': None, 'ts': None, 'raw_value': None, '__class__': 'qcodes.instrument.parameter.Parameter', 'full_name': 'keithley1_readnext', 'unit': '', 'instrument': 'qtt.instrument_drivers.virtual_instruments.VirtualMeter', 'instrument_name': 'keithley1', 'label': 'keithley1', 'inter_delay': 0, 'name': 'readnext', 'post_delay': 0}}, 'name': 'keithley1'}

snapshot = station.snapshot()
print(snapshot.keys())

dict_keys(['instruments', 'parameters', 'components', 'default_measurement', 'metadata'])

After all experiments are over, all devices need to be disconnected. The virtual_dot_array has a close function to stop and clean up all the instrument resources:

virtual_dot_array.close()

close gates: gates (16 gates)
close <VirtualMeter: keithley1>
close <VirtualMeter: keithley3>
close <VirtualMeter: keithley4>
close VirtualIVVI: ivvi1
close VirtualIVVI: ivvi2
close <SimulationAWG: vawg>
close <SimulationDigitizer: sdigitizer>

For your own setup to have to write your own close function.