SPI Rack

QCoDeS driver

class spi_rack.spi_rack.dummy_spi_api(address, baud_rate, timeout=1.0)

Bases: object

” A dummy API that can be used to test the SPI rack driver.

TEMPERATURE = 25.0

BATTERY_LVLS = [6.0, -6.0]

FIRMWARE_VERSION = 'v1.0'

__init__(address, baud_rate, timeout=1.0)

Instantiates the dummy API object.

Parameters

• address – Mock value for the address on which the spi_rack is connected. This value is assigned to a member variable, but is not actually used.

• address – Mock value for the baud_rate for the serial connection. This value is assigned to a member variable, but is not actually used.

• timeout – Mock value for the timeout for the serial connection. This value is assigned to a member variable, but is not actually used.

get_temperature() → float

Return a mock temperature.

Returns

returns dummy_spi_api.TEMPERATURE

Return type

float

get_battery() → List[float]

Return a mock battery level list. In the actual API these are two values read from the battery ADCs. For the mock API simply constant values are returned. The expected values to be returned can also be gotten through dummy_spi_api.BATTERY_LVLS.

Returns

returns dummy_spi_api.BATTERY_LVLS

Return type

List[float]

get_firmware_version() → str

Returns a firmware version string. In the actual API this is returned by the microcontroller.

Returns

returns dummy_spi_api.FIRMWARE_VERSION

Return type

str

close()

Not relevant for dummy api but added to remove errors

unlock()

Unlocks the communication to the microcontroller. Since for the dummy implementation there is no communication to the microcontroller, this simply sets a self.locked to False.

class spi_rack.spi_rack.spi_rack(name: str, address: str, baud_rate: int = 9600, timeout: float = 1, dummy_api: Optional[Type[spi_rack.spi_rack.dummy_spi_api]] = None)

Bases: qcodes.instrument.base.Instrument

SPI rack driver class based on QCoDeS <https://qcodes.github.io/Qcodes/>. This class relies on the spirack API <https://github.com/mtiggelman/SPI-rack/>.

Example usage:

from spi_rack.spi_rack import spi_rack
from spi_rack.S4g_module import S4g_module

spi = spi_rack("my_spi_rack", "COM4")
spi.add_spi_module(2, "S4g", "bob")     # adds an S4g module with address 2 named "bob"
spi.add_spi_module(6, S4g_module)       # adds an S4g module with address 6 with the default name module6

spi.bob.dac0.current(10e-3)             # sets the current of output 0 of the S4g module named "bob" to 10 mA

__init__(name: str, address: str, baud_rate: int = 9600, timeout: float = 1, dummy_api: Optional[Type[spi_rack.spi_rack.dummy_spi_api]] = None)

Instantiates the driver object.

Parameters

• name (str) – Instrument name.

• address (str) – COM port used by SPI rack controller unit (e.g. “COM4”)

• baud_rate (int) – Baud rate

• timeout (float) – Data receive timeout in seconds

• dummy_api (Type[dummy_spi_api]) – If the dummy API is passed instead of None, the SPI rack driver is operating in “dummy” mode for testing purposes.

add_spi_module(address: int, module_type: Union[spi_rack.spi_module_base.spi_module_base, str], name: Optional[str] = None, **kwargs)

Add a module to the driver.

Parameters

• address (int) – Address that the module is set to (set internally on the module itself with a jumper).

• module_type (Union[str, spi_module_base]) – Either a str that is defined in _MODULES_MAP, or a reference to a class derived from SPI_Module_Base.

• name (str) – Optional name of the module. If no name is given or is None, a default name of “module{address}” is used.

Raises

ValueError – module_type is not a string or a subclass of SPI_Module_Base

get_idn()

Generates the IDN dict.

Returns

The QCoDeS style IDN dictionary. Currently only the firmware version is actually read from hardware.

Return type

dict

close()

Closes connection to hardware and closes the Instrument.

set_dacs_zero()

Calls the set_dacs_zero() function on all the modules, which in turn should cause all output values to be set to 0.

connect_message(idn_param: str = 'IDN', begin_time: Optional[float] = None) → None

Print a standard message on initial connection to an instrument. Overridden from superclass to accommodate IEEE488.2 for IDN.

Parameters

• idn_param (str) – Name of parameter that returns ID dict. Default IDN.

• begin_time (Optional[float]) – time.time() when init started. Default is self._t0, set at start of Instrument.__init__.

class spi_rack.spi_module_base.spi_module_base(parent, name: str, address: int, **kwargs)

Bases: qcodes.instrument.channel.InstrumentChannel

Defines an abstract base class for SPI modules. All module drivers should inherit from this class.

This class defines no actual functionality but rather serves to provide a common interface shared among all modules.

Parameters

• parent – Reference to the spi_rack parent object. This is handled by the add_spi_module function.

• name (str) – Name given to the InstrumentChannel.

• address (int) – Module number set on the hardware (set internally on the module itself with a jumper).

__init__(parent, name: str, address: int, **kwargs)

abstract set_dacs_zero()

” Base method for set_dacs_zero. Should be overridden by subclass.

class spi_rack.spi_module_base.dummy_spi_module(parent, name: str, address: int)

Bases: spi_rack.spi_module_base.spi_module_base

A dummy implementation of module driver, used for mock implementations.

__init__(parent, name: str, address: int)

set_dacs_zero()

” Base method for set_dacs_zero. Should be overridden by subclass.

QCoDeS parameters

spi_rack.IDN

Please see QCoDeS for a description.

Properties

• value: Anything

spi_rack.temperature

Returns the temperature in the C1b module. Reads the temperature from the internal C1b temperature sensor. Accuracy is +- 0.5 degrees in 0-70 degree range.

Properties

• unit: C

• value: on

spi_rack.battery_voltages

Calculates the battery voltages from the ADC channel values. Returns: [VbatPlus, VbatMin]

Properties

• unit: V

• value: on

S4g module

class spi_rack.s4g_module.s4g_module(parent, name: str, address: int, reset_currents: bool = True, dac_names: Optional[List[str]] = None)

Bases: spi_rack.spi_module_base.spi_module_base

QCoDeS <https://qcodes.github.io/Qcodes/>- style instrument channel driver for the S4g SPI module.

NUMBER_OF_DACS = 4

__init__(parent, name: str, address: int, reset_currents: bool = True, dac_names: Optional[List[str]] = None)

Instantiates the driver object. This is the object that should be instantiated by the add_spi_module function.

Parameters

• parent – Reference to the spi_rack parent object. This is handled by the add_spi_module function.

• name (str) – Name given to the InstrumentChannel.

• address (int) – Module number set on the hardware.

• reset_currents (bool) – If True, then reset all currents to zero and change the span to range_max_bi.

• dac_names (List[str]) – List of all the names to use for the dac channels. If no list is given or is None, the default name “dac{i}” is used for the i-th dac channel.

Raises

ValueError – Length of the dac names list does not match the number of dacs.

set_dacs_zero()

Sets all currents of all outputs to 0.

class spi_rack.s4g_module.s4g_dac_channel(parent: spi_rack.s4g_module.s4g_module, name: str, dac: int)

Bases: qcodes.instrument.channel.InstrumentChannel

QCoDeS <https://qcodes.github.io/Qcodes/>- style instrument channel driver for the dac channels of the S4g module. This class is used by the S4g_module to define the individual dac channels and should not be used directly.

__init__(parent: spi_rack.s4g_module.s4g_module, name: str, dac: int)

Constructor for the dac channel instrument channel.

Parameters

• parent (s4g_module) – Reference to the parent s4g_module

• name (str) – Name for the instrument channel

• dac (int) – Number of the dac that this channel corresponds to

set_current_instant(dac, val)

” Wrapper function around the set_current API call.