# ----------------------------------------------------------------------------
# Description : D5a SPI module native interface
# Git repository : https://gitlab.com/qblox/packages/software/qblox_instruments.git
# Copyright (C) Qblox BV (2021)
# ----------------------------------------------------------------------------
import numpy as np
import threading
from time import sleep
from typing import List, Optional, Tuple
from spirack.D5a_module import D5a_module as D5aApi
from qblox_instruments.native.spi_rack_modules import SpiModuleBase
class DummyD5aApi:
"""
Mock implementation of
`spirack API <https://github.com/mtiggelman/SPI-rack/blob/master/spirack/D5a_module.py>`_,
for use with the dummy drivers.
"""
# DAC software span constants
range_4V_uni = 0
range_4V_bi = 2
range_8V_uni = 1
range_8V_bi = 3
range_2V_bi = 4
SPAN_MAPPING = {
"range_4V_uni": range_4V_uni,
"range_8V_uni": range_8V_uni,
"range_4V_bi": range_4V_bi,
"range_8V_bi": range_8V_bi,
"range_2V_bi": range_2V_bi,
}
DAC_RESOLUTION = 2**18
def __init__(
self, spi_rack, module: int, reset_voltages: bool = True, num_dacs: int = 16
):
"""
Instantiates the mock communication layer with identical parameters to
the `spirack.D5a_module.D5a_module` constructor.
Parameters
----------
spi_rack : DummySpiApi
Mock SPI_rack class object via which the communication runs
module : int
module number set on the hardware
reset_voltages : bool
if True, then reset all voltages to zero and change the span
to `range_4V_bi`. If a voltage jump would occur, then ramp
to zero in steps of 10 mV
num_dacs: int
number of DAC channels available
Returns
----------
"""
self.parent = spi_rack
self._voltages = [0.0] * num_dacs
init_span = self.SPAN_MAPPING["range_4V_bi"] if reset_voltages else 0
self._num_dacs = num_dacs
self._spans = [init_span] * num_dacs
self.address = module
def change_span_update(self, DAC: int, span: int) -> None:
"""
Mocks the `change_span_update` function of the API.
Parameters
----------
DAC : int
Current output of which to change the span
span : int
Values for the span as mentioned in the datasheet, use from
SPAN_MAPPING
Returns
----------
"""
self._spans[DAC] = span
def change_span(self, DAC: int, span: int) -> None:
"""
Mocks the `change_span` function of the API.
Parameters
----------
DAC : int
Current output of which to change the span
span : int
Values for the span as mentioned in the datasheet, use from
SPAN_MAPPING
Returns
----------
"""
self.change_span_update(DAC, span)
def set_voltage(self, DAC: int, voltage: float) -> None:
"""
Mocks the `set_voltage` function of the API
Parameters
----------
DAC: int
DAC inside the module of which to update the voltage
voltage: float
new DAC voltage
Returns
----------
"""
self._voltages[DAC] = voltage
def get_settings(self, DAC: int) -> Tuple[float, int]:
"""
Mocks the `get_settings` function of the API
Parameters
----------
DAC : int
Current output of which the settings will be read
Returns
----------
float
voltage
int
span
"""
return self._voltages[DAC], self._spans[DAC]
def get_stepsize(self, DAC: int) -> float:
"""
Mocks the `get_stepsize` function of the API.
Parameters
----------
DAC : int
DAC inside the module of which the stepsize is calculated
Returns
----------
float
Smallest voltage step possible with DAC
"""
if DAC not in range(self._num_dacs):
raise ValueError(
f"D5a module {self.address} [get_stepsize]: DAC {DAC} does not exist."
)
voltage_ranges = {
"range_4V_uni": 4.0,
"range_8V_uni": 8.0,
"range_4V_bi": 8.0,
"range_8V_bi": 16.0,
"range_2V_bi": 4,
}
# Reverse dict lookup
span_as_str = next(
key for key, value in self.SPAN_MAPPING.items() if value == self._spans[DAC]
)
return voltage_ranges[span_as_str] / self.DAC_RESOLUTION
[docs]
class D5aModule(SpiModuleBase):
"""
Native driver for the D5a SPI module.
"""
NUMBER_OF_DACS = 16 # Set by hardware constraints
[docs]
def __init__(
self,
parent,
name: str,
address: int,
reset_voltages: bool = False,
dac_names: Optional[List[str]] = None,
is_dummy: bool = False,
):
"""
Instantiates the driver object. This is the object that should be
instantiated by the
:func:`~qblox_instruments.native.SpiRack.add_spi_module` function.
Parameters
----------
parent
Reference to the :class:`~qblox_instruments.native.SpiRack` parent
object. This is handled by the
:func:`~qblox_instruments.native.SpiRack.add_spi_module` function.
name : str
Name given to the InstrumentChannel.
address : int
Module number set on the hardware.
reset_voltages : bool
If True, then reset all voltages to zero and change the span to
`range_max_bi`.
dac_names : Optional[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.
is_dummy : bool
If true, do not connect to physical hardware, but use dummy module.
Returns
----------
Raises
----------
ValueError
Length of the dac names list does not match the number of dacs.
"""
super().__init__(parent, name, address)
api = DummyD5aApi if is_dummy else D5aApi
self.api = api(
parent.spi_rack,
module=address,
reset_voltages=reset_voltages,
num_dacs=self.NUMBER_OF_DACS,
)
self._channels = []
for dac in range(self.NUMBER_OF_DACS):
if dac_names is None:
ch_name = f"dac{dac}"
elif len(dac_names) == self.NUMBER_OF_DACS:
ch_name = dac_names[dac]
else:
raise ValueError(f"Length of dac_names must be {self.NUMBER_OF_DACS}")
channel = D5aDacChannel(self, ch_name)
self._channels.append(channel)
[docs]
def set_dacs_zero(self) -> None:
"""
Sets all voltages of all outputs to 0.
Returns
----------
"""
for ch in self._channels:
ch.voltage(0)
class D5aDacChannel:
"""
Native driver for the dac channels of the D5a module. This class is used
by the :class:`~qblox_instruments.native.spi_rack_modules.D5aModule` to
define the individual dac channels and should not be used directly.
"""
def __init__(self, parent: D5aModule, name: str):
"""
Constructor for the dac channel instrument channel.
Parameters
----------
parent : D5aModule
Reference to the parent
:class:`~qblox_instruments.native.spi_rack_modules.D5aModule`
name : str
Name for the instrument channel
dac : int
Number of the dac that this channel corresponds to
Returns
----------
Raises
----------
"""
self._api = parent.api
self._chan_name = name
self._ramping_enabled = False
self._ramp_rate = 100e-3
self._ramp_max_step = 100e-3
self._is_ramping = False
self._ramp_thread = None
def _get_span(self, dac: int) -> int:
"""
Gets the span set by the module.
Parameters
----------
dac : int
the dac of which to get the span
Returns
----------
int
The current span
"""
_, span = self._api.get_settings(dac)
return span
def _set_span(self, dac: int, val: int) -> None:
"""
Sets the span set by the module.
Parameters
----------
dac : int
the dac of which to set the span
val: int
The integer representation of the new spen
Raises
----------
ValueError
When the present current on the output does not fit into the new span
"""
v, _ = self._api.get_settings(dac)
# check if v fits into the new span
if val == self._api.range_4V_uni:
maxV = 4.0
minV = 0.0
elif val == self._api.range_4V_bi:
maxV = 4.0
minV = -4.0
if val == self._api.range_8V_uni:
maxV = 8.0
minV = 0.0
elif val == self._api.range_8V_bi:
maxV = 8.0
minV = -8.0
elif val == self._api.range_2V_bi:
maxV = 2.0
minV = -2.0
if v < minV or v > maxV:
raise ValueError(
f"Present voltage is {v} V, which is out of the range [{minV} V, {maxV } V], the newly selected span"
)
self._api.change_span(dac, val)
self.set_voltage_instant(dac, v)
def _get_voltage(self, dac: int) -> float:
""" "
Gets the voltage set by the module.
Parameters
----------
dac : int
the dac of which to get the voltage
Returns
----------
float
The output voltage reported by the hardware
"""
voltage, _ = self._api.get_settings(dac)
return voltage
def _set_voltage(self, dac: int, val: float) -> None:
"""
Sets the voltage either through ramping or instantly.
Parameters
----------
dac : int
the dac of which to set the voltage
val : float
The new value of the voltage
Returns
----------
"""
if self._ramping_enabled:
self._set_voltage_ramp(dac, val)
else:
self.set_voltage_instant(dac, val)
def set_voltage_instant(self, dac: int, val: float) -> None:
""" "
Wrapper function around the set_voltage API call. Instantaneously sets
the voltage.
Parameters
----------
dac : int
the dac of which to set the voltage
val : float
The new value of the voltage
Returns
----------
"""
self._api.get_settings(dac)
self._api.set_voltage(dac, val)
def _set_voltage_ramp(self, dac: int, val: float) -> None:
"""
Ramps the voltage in steps set by `ramp_max_step` with a rate set by
`ramp_rate`. Ramping is non-blocking so the user should check
`is_ramping() == False` to see if the final value is reached.
Parameters
----------
dac : int
the dac of which to set the voltage
val : float
The new value of the voltage after ramping
Returns
----------
"""
class RampThread(threading.Thread):
"""
Inner class that defines a thread that can be safely killed.
"""
def __init__(self, *args, **kwargs):
super().__init__(target=self.worker_function, *args, **kwargs)
self._stopped = False
def worker_function(self, ch, dac, vals, dt):
"""
Conducts the actual ramping
"""
for val in vals:
if self._stopped:
return
sleep(dt)
ch.set_voltage_instant(dac, val)
ch._is_ramping = False
def exit(self):
"""
Stops the thread.
"""
self._stopped = True
# Start of function code
# Stop ramping to the value set previously, and ramp to new value.
if self._is_ramping:
self._ramp_thread.exit()
self._is_ramping = True
val_begin = self._get_voltage(dac)
num_steps = int(np.ceil(np.abs(val_begin - val) / self._ramp_max_step))
vals = np.linspace(val_begin, val, num_steps)
dt = np.abs(val_begin - val) / self._ramp_rate / num_steps
th = RampThread(args=(self, dac, vals, dt))
self._ramp_thread = th
th.start()
