Source code for qcodes.instrument_drivers.american_magnetics.AMI430_visa

import collections
import collections.abc
import logging
import numbers
import time
import warnings
from collections import defaultdict
from contextlib import ExitStack
from functools import partial
from typing import (
    Any,
    Callable,
    Iterable,
    List,
    Optional,
    Sequence,
    Tuple,
    TypeVar,
    Union,
)

import numpy as np
from pyvisa import VisaIOError

from qcodes.instrument import Instrument, InstrumentChannel, VisaInstrument
from qcodes.math_utils import FieldVector
from qcodes.parameters import Parameter
from qcodes.utils import QCoDeSDeprecationWarning
from qcodes.validators import Anything, Bool, Enum, Ints, Numbers

log = logging.getLogger(__name__)

CartesianFieldLimitFunction = Callable[[float, float, float], bool]

T = TypeVar("T")


[docs]class AMI430Exception(Exception): pass
[docs]class AMI430Warning(UserWarning): pass
[docs]class AMI430SwitchHeater(InstrumentChannel): class _Decorators: @classmethod def check_enabled(cls, f: Callable[..., T]) -> Callable[..., T]: def check_enabled_decorator( self: "AMI430SwitchHeater", *args: Any, **kwargs: Any ) -> T: if not self.check_enabled(): raise AMI430Exception("Switch not enabled") return f(self, *args, **kwargs) return check_enabled_decorator def __init__(self, parent: "AMI430") -> None: super().__init__(parent, "SwitchHeater") # Add state parameters self.add_parameter( "enabled", label="Switch Heater Enabled", get_cmd=self.check_enabled, set_cmd=lambda x: (self.enable() if x else self.disable()), vals=Bool(), ) self.add_parameter( "state", label="Switch Heater On", get_cmd=self.check_state, set_cmd=lambda x: (self.on() if x else self.off()), vals=Bool(), ) self.add_parameter( "in_persistent_mode", label="Persistent Mode", get_cmd="PERS?", val_mapping={True: 1, False: 0}, ) # Configuration Parameters self.add_parameter( "current", label="Switch Heater Current", unit="mA", get_cmd="PS:CURR?", get_parser=float, set_cmd="CONF:PS:CURR {}", vals=Numbers(0, 125), ) self.add_parameter( "heat_time", label="Heating Time", unit="s", get_cmd="PS:HTIME?", get_parser=int, set_cmd="CONF:PS:HTIME {}", vals=Ints(5, 120), ) self.add_parameter( "cool_time", label="Cooling Time", unit="s", get_cmd="PS:CTIME?", get_parser=int, set_cmd="CONF:PS:CTIME {}", vals=Ints(5, 3600), )
[docs] def disable(self) -> None: """Turn measurement off""" self.write("CONF:PS 0") self._enabled = False
[docs] def enable(self) -> None: """Turn measurement on""" self.write("CONF:PS 1") self._enabled = True
[docs] def check_enabled(self) -> bool: return bool(int(self.ask("PS:INST?").strip()))
[docs] @_Decorators.check_enabled def on(self) -> None: self.write("PS 1") while self._parent.ramping_state() == "heating switch": self._parent._sleep(0.5)
[docs] @_Decorators.check_enabled def off(self) -> None: self.write("PS 0") while self._parent.ramping_state() == "cooling switch": self._parent._sleep(0.5)
[docs] @_Decorators.check_enabled def check_state(self) -> bool: return bool(int(self.ask("PS?").strip()))
[docs]class AMI430(VisaInstrument): """ Driver for the American Magnetics Model 430 magnet power supply programmer. This class controls a single magnet power supply. In order to use two or three magnets simultaneously to set field vectors, first instantiate the individual magnets using this class and then pass them as arguments to either the AMI430_2D or AMI430_3D virtual instrument classes. Args: name: a name for the instrument address: VISA formatted address of the power supply programmer. Of the form ``TCPIP[board]::host address::port::SOCKET`` e.g. ``TCPIP0::192.168.0.1::7800::SOCKET`` current_ramp_limit: A current ramp limit, in units of A/s """ _SHORT_UNITS = {"seconds": "s", "minutes": "min", "tesla": "T", "kilogauss": "kG"} _DEFAULT_CURRENT_RAMP_LIMIT = 0.06 # [A/s] _RETRY_WRITE_ASK = True _RETRY_TIME = 5 def __init__( self, name: str, address: str, reset: bool = False, terminator: str = "\r\n", current_ramp_limit: Optional[float] = None, **kwargs: Any, ): if "has_current_rating" in kwargs.keys(): warnings.warn( "'has_current_rating' kwarg to AMI430 " "is deprecated and has no effect", category=QCoDeSDeprecationWarning, ) kwargs.pop("has_current_rating") super().__init__( name, address, terminator=terminator, **kwargs, ) simmode = getattr(self, "visabackend", False) == "sim" # pyvisa-sim does not support connect messages if not simmode: # the AMI 430 sends a welcome message of # 'American Magnetics Model 430 IP Interface' # 'Hello' # here we read that out before communicating with the instrument # if that is not the first reply likely there is left over messages # in the buffer so read until empty message1 = self.visa_handle.read() if "American Magnetics Model 430 IP Interface" not in message1: try: while True: self.visa_handle.read() except VisaIOError: pass else: # read the hello part of the welcome message self.visa_handle.read() self._parent_instrument = None # Add reset function self.add_function("reset", call_cmd="*RST") if reset: self.reset() # Add parameters setting instrument units self.add_parameter( "ramp_rate_units", get_cmd="RAMP:RATE:UNITS?", set_cmd=(lambda units: self._update_units(ramp_rate_units=units)), val_mapping={"seconds": 0, "minutes": 1}, ) self.add_parameter( "field_units", get_cmd="FIELD:UNITS?", set_cmd=(lambda units: self._update_units(field_units=units)), val_mapping={"kilogauss": 0, "tesla": 1}, ) # Set programmatic safety limits self.add_parameter( "current_ramp_limit", get_cmd=lambda: self._current_ramp_limit, set_cmd=self._update_ramp_rate_limit, unit="A/s", ) self.add_parameter( "field_ramp_limit", get_cmd=lambda: self.current_ramp_limit(), set_cmd=lambda x: self.current_ramp_limit(x), scale=1 / float(self.ask("COIL?")), unit="T/s", ) if current_ramp_limit is None: self._update_ramp_rate_limit( AMI430._DEFAULT_CURRENT_RAMP_LIMIT, update=False ) else: self._update_ramp_rate_limit(current_ramp_limit, update=False) # Add solenoid parameters self.add_parameter( "coil_constant", get_cmd=self._update_coil_constant, set_cmd=self._update_coil_constant, vals=Numbers(0.001, 999.99999), ) self.add_parameter( "current_limit", unit="A", set_cmd="CONF:CURR:LIMIT {}", get_cmd="CURR:LIMIT?", get_parser=float, vals=Numbers(0, 80), ) # what are good numbers here? self.add_parameter( "field_limit", set_cmd=self.current_limit.set, get_cmd=self.current_limit.get, scale=1 / float(self.ask("COIL?")), ) # Add current solenoid parameters # Note that field is validated in set_field self.add_parameter( "field", get_cmd="FIELD:MAG?", get_parser=float, set_cmd=self.set_field ) self.add_parameter( "ramp_rate", get_cmd=self._get_ramp_rate, set_cmd=self._set_ramp_rate ) self.add_parameter("setpoint", get_cmd="FIELD:TARG?", get_parser=float) self.add_parameter( "is_quenched", get_cmd="QU?", val_mapping={True: 1, False: 0} ) self.add_function("reset_quench", call_cmd="QU 0") self.add_function("set_quenched", call_cmd="QU 1") self.add_parameter( "ramping_state", get_cmd="STATE?", get_parser=int, val_mapping={ "ramping": 1, "holding": 2, "paused": 3, "manual up": 4, "manual down": 5, "zeroing current": 6, "quench detected": 7, "at zero current": 8, "heating switch": 9, "cooling switch": 10, }, ) self.add_parameter( "ramping_state_check_interval", initial_value=0.05, unit="s", vals=Numbers(0, 10), set_cmd=None, ) # Add persistent switch switch_heater = AMI430SwitchHeater(self) self.add_submodule("switch_heater", switch_heater) # Add interaction functions self.add_function("get_error", call_cmd="SYST:ERR?") self.add_function("ramp", call_cmd="RAMP") self.add_function("pause", call_cmd="PAUSE") self.add_function("zero", call_cmd="ZERO") # Correctly assign all units self._update_units() self.connect_message() def _sleep(self, t: float) -> None: """ Sleep for a number of seconds t. If we are or using the PyVISA 'sim' backend, omit this """ simmode = getattr(self, "visabackend", False) == "sim" if simmode: return else: time.sleep(t) def _can_start_ramping(self) -> bool: """ Check the current state of the magnet to see if we can start ramping """ if self.is_quenched(): logging.error(__name__ + ": Could not ramp because of quench") return False if self.switch_heater.in_persistent_mode(): logging.error(__name__ + ": Could not ramp because persistent") return False state = self.ramping_state() if state == "ramping": # If we don't have a persistent switch, or it's warm if not self.switch_heater.enabled(): return True elif self.switch_heater.state(): return True elif state in ["holding", "paused", "at zero current"]: return True logging.error(__name__ + f": Could not ramp, state: {state}") return False
[docs] def set_field( self, value: float, *, block: bool = True, perform_safety_check: bool = True ) -> None: """ Ramp to a certain field Args: value: Value to ramp to. block: Whether to wait unit the field has finished setting perform_safety_check: Whether to set the field via a parent driver (if present), which might perform additional safety checks. """ # Check we aren't violating field limits field_lim = float(self.ask("COIL?")) * self.current_limit() if np.abs(value) > field_lim: msg = "Aborted _set_field; {} is higher than limit of {}" raise ValueError(msg.format(value, field_lim)) # If part of a parent driver, set the value using that driver if self._parent_instrument is not None and perform_safety_check: self._parent_instrument._request_field_change(self, value) return # Check we can ramp if not self._can_start_ramping(): raise AMI430Exception( f"Cannot ramp in current state: " f"state is {self.ramping_state()}" ) # Then, do the actual ramp self.pause() # Set the ramp target self.write(f"CONF:FIELD:TARG {value}") # If we have a persistent switch, make sure it is resistive if self.switch_heater.enabled(): if not self.switch_heater.state(): raise AMI430Exception("Switch heater is not on") self.ramp() # Check if we want to block if not block: return # Otherwise, wait until no longer ramping self.log.debug(f"Starting blocking ramp of {self.name} to {value}") exit_state = self.wait_while_ramping() self.log.debug(f"Finished blocking ramp") # If we are now holding, it was successful if exit_state != "holding": msg = "_set_field({}) failed with state: {}" raise AMI430Exception(msg.format(value, exit_state))
[docs] def wait_while_ramping(self) -> str: while self.ramping_state() == "ramping": self._sleep(self.ramping_state_check_interval()) return self.ramping_state()
def _get_ramp_rate(self) -> float: """Return the ramp rate of the first segment in Tesla per second""" results = self.ask("RAMP:RATE:FIELD:1?").split(",") return float(results[0]) def _set_ramp_rate(self, rate: float) -> None: """Set the ramp rate of the first segment in Tesla per second""" if rate > self.field_ramp_limit(): raise ValueError( f"{rate} {self.ramp_rate.unit} " f"is above the ramp rate limit of " f"{self.field_ramp_limit()} " f"{self.field_ramp_limit()}" ) self.write("CONF:RAMP:RATE:SEG 1") self.write(f"CONF:RAMP:RATE:FIELD 1,{rate},0") def _update_ramp_rate_limit( self, new_current_rate_limit: float, update: bool = True ) -> None: """ Update the maximum current ramp rate The value passed here is scaled by the units set in self.ramp_rate_units """ # Update ramp limit self._current_ramp_limit = new_current_rate_limit # And update instrument limits if update: field_ramp_limit = self.field_ramp_limit() if self.ramp_rate() > field_ramp_limit: self.ramp_rate(field_ramp_limit) def _update_coil_constant(self, new_coil_constant: Optional[float] = None) -> float: """ Update the coil constant and relevant scaling factors. If new_coil_constant is none, query the coil constant from the instrument """ # Query coil constant from instrument if new_coil_constant is None: new_coil_constant = float(self.ask("COIL?")) else: self.write(f"CONF:COIL {new_coil_constant}") # Update scaling factors self.field_ramp_limit.scale = 1 / new_coil_constant self.field_limit.scale = 1 / new_coil_constant # Return new coil constant return new_coil_constant def _update_units( self, ramp_rate_units: Optional[int] = None, field_units: Optional[int] = None ) -> None: # Get or set units on device if ramp_rate_units is None: ramp_rate_units_int: str = self.ramp_rate_units() else: self.write(f"CONF:RAMP:RATE:UNITS {ramp_rate_units}") ramp_rate_units_int = self.ramp_rate_units.inverse_val_mapping[ ramp_rate_units ] if field_units is None: field_units_int: str = self.field_units() else: self.write(f"CONF:FIELD:UNITS {field_units}") field_units_int = self.field_units.inverse_val_mapping[field_units] # Map to shortened unit names ramp_rate_units_short = AMI430._SHORT_UNITS[ramp_rate_units_int] field_units_short = AMI430._SHORT_UNITS[field_units_int] # And update all units self.coil_constant.unit = f"{field_units_short}/A" self.field_limit.unit = f"{field_units_short}" self.field.unit = f"{field_units_short}" self.setpoint.unit = f"{field_units_short}" self.ramp_rate.unit = f"{field_units_short}/{ramp_rate_units_short}" self.current_ramp_limit.unit = f"A/{ramp_rate_units_short}" self.field_ramp_limit.unit = f"{field_units_short}/{ramp_rate_units_short}" # And update scaling factors # Note: we don't update field_ramp_limit scale as it redirects # to ramp_rate_limit; we don't update ramp_rate units as # the instrument stores changed units if ramp_rate_units_short == "min": self.current_ramp_limit.scale = 1 / 60 else: self.current_ramp_limit.scale = 1 # If the field units change, the value of the coil constant also # changes, hence we read the new value of the coil constant from the # instrument via the `coil_constant` parameter (which in turn also # updates settings of some parameters due to the fact that the coil # constant changes) self.coil_constant()
[docs] def write_raw(self, cmd: str) -> None: try: super().write_raw(cmd) except VisaIOError as err: # The ami communication has found to be unstable # so we retry the communication here msg = f"Got VisaIOError while writing {cmd} to instrument." if self._RETRY_WRITE_ASK: msg += f" Will retry in {self._RETRY_TIME} sec." self.log.exception(msg) if self._RETRY_WRITE_ASK: time.sleep(self._RETRY_TIME) self.device_clear() super().write_raw(cmd) else: raise err
[docs] def ask_raw(self, cmd: str) -> str: try: result = super().ask_raw(cmd) except VisaIOError as err: # The ami communication has found to be unstable # so we retry the communication here msg = f"Got VisaIOError while asking the instrument: {cmd}" if self._RETRY_WRITE_ASK: msg += f" Will retry in {self._RETRY_TIME} sec." self.log.exception(msg) if self._RETRY_WRITE_ASK: time.sleep(self._RETRY_TIME) self.device_clear() result = super().ask_raw(cmd) else: raise err return result
[docs]class AMI430_3D(Instrument): def __init__( self, name: str, instrument_x: Union[AMI430, str], instrument_y: Union[AMI430, str], instrument_z: Union[AMI430, str], field_limit: Union[numbers.Real, Iterable[CartesianFieldLimitFunction]], **kwargs: Any, ): """ Driver for controlling three American Magnetics Model 430 magnet power supplies simultaneously for setting magnetic field vectors. The individual magnet power supplies can be passed in as either instances of AMI430 driver or as names of existing AMI430 instances. In the latter case, the instances will be found via the passed names. Args: name: a name for the instrument instrument_x: AMI430 instance or a names of existing AMI430 instance for controlling the X axis of magnetic field instrument_y: AMI430 instance or a names of existing AMI430 instance for controlling the Y axis of magnetic field instrument_z: AMI430 instance or a names of existing AMI430 instance for controlling the Z axis of magnetic field field_limit: a number for maximum allows magnetic field or an iterable of callable field limit functions that define region(s) of allowed values in 3D magnetic field space """ super().__init__(name, **kwargs) if not isinstance(name, str): raise ValueError("Name should be a string") for instrument, arg_name in zip( (instrument_x, instrument_y, instrument_z), ("instrument_x", "instrument_y", "instrument_z"), ): if not isinstance(instrument, (AMI430, str)): raise ValueError( f"Instruments need to be instances of the class AMI430 " f"or be valid names of already instantiated instances " f"of AMI430 class; {arg_name} argument is " f"neither of those" ) def find_ami430_with_name(ami430_name: str) -> AMI430: found_ami430 = AMI430.find_instrument( name=ami430_name, instrument_class=AMI430 ) return found_ami430 self._instrument_x = ( instrument_x if isinstance(instrument_x, AMI430) else find_ami430_with_name(instrument_x) ) self._instrument_y = ( instrument_y if isinstance(instrument_y, AMI430) else find_ami430_with_name(instrument_y) ) self._instrument_z = ( instrument_z if isinstance(instrument_z, AMI430) else find_ami430_with_name(instrument_z) ) self._field_limit: Union[float, Iterable[CartesianFieldLimitFunction]] if isinstance(field_limit, collections.abc.Iterable): self._field_limit = field_limit elif isinstance(field_limit, numbers.Real): # Conversion to float makes related driver logic simpler self._field_limit = float(field_limit) else: raise ValueError( "field limit should either be a number or " "an iterable of callable field limit functions." ) self._set_point = FieldVector( x=self._instrument_x.field(), y=self._instrument_y.field(), z=self._instrument_z.field(), ) # Get-only parameters that return a measured value self.add_parameter( "cartesian_measured", get_cmd=partial(self._get_measured, "x", "y", "z"), unit="T", ) self.add_parameter( "x_measured", get_cmd=partial(self._get_measured, "x"), unit="T" ) self.add_parameter( "y_measured", get_cmd=partial(self._get_measured, "y"), unit="T" ) self.add_parameter( "z_measured", get_cmd=partial(self._get_measured, "z"), unit="T" ) self.add_parameter( "spherical_measured", get_cmd=partial(self._get_measured, "r", "theta", "phi"), unit="T", ) self.add_parameter( "phi_measured", get_cmd=partial(self._get_measured, "phi"), unit="deg" ) self.add_parameter( "theta_measured", get_cmd=partial(self._get_measured, "theta"), unit="deg" ) self.add_parameter( "field_measured", get_cmd=partial(self._get_measured, "r"), unit="T" ) self.add_parameter( "cylindrical_measured", get_cmd=partial(self._get_measured, "rho", "phi", "z"), unit="T", ) self.add_parameter( "rho_measured", get_cmd=partial(self._get_measured, "rho"), unit="T" ) # Get and set parameters for the set points of the coordinates self.add_parameter( "cartesian", get_cmd=partial(self._get_setpoints, ("x", "y", "z")), set_cmd=partial(self._set_setpoints, ("x", "y", "z")), unit="T", vals=Anything(), ) self.add_parameter( "x", get_cmd=partial(self._get_setpoints, ("x",)), set_cmd=partial(self._set_setpoints, ("x",)), unit="T", vals=Numbers(), ) self.add_parameter( "y", get_cmd=partial(self._get_setpoints, ("y",)), set_cmd=partial(self._set_setpoints, ("y",)), unit="T", vals=Numbers(), ) self.add_parameter( "z", get_cmd=partial(self._get_setpoints, ("z",)), set_cmd=partial(self._set_setpoints, ("z",)), unit="T", vals=Numbers(), ) self.add_parameter( "spherical", get_cmd=partial(self._get_setpoints, ("r", "theta", "phi")), set_cmd=partial(self._set_setpoints, ("r", "theta", "phi")), unit="tuple?", vals=Anything(), ) self.add_parameter( "phi", get_cmd=partial(self._get_setpoints, ("phi",)), set_cmd=partial(self._set_setpoints, ("phi",)), unit="deg", vals=Numbers(), ) self.add_parameter( "theta", get_cmd=partial(self._get_setpoints, ("theta",)), set_cmd=partial(self._set_setpoints, ("theta",)), unit="deg", vals=Numbers(), ) self.add_parameter( "field", get_cmd=partial(self._get_setpoints, ("r",)), set_cmd=partial(self._set_setpoints, ("r",)), unit="T", vals=Numbers(), ) self.add_parameter( "cylindrical", get_cmd=partial(self._get_setpoints, ("rho", "phi", "z")), set_cmd=partial(self._set_setpoints, ("rho", "phi", "z")), unit="tuple?", vals=Anything(), ) self.add_parameter( "rho", get_cmd=partial(self._get_setpoints, ("rho",)), set_cmd=partial(self._set_setpoints, ("rho",)), unit="T", vals=Numbers(), ) self.add_parameter( "block_during_ramp", set_cmd=None, initial_value=True, unit="", vals=Bool() ) self.ramp_mode = Parameter( name="ramp_mode", instrument=self, get_cmd=None, set_cmd=None, vals=Enum("default", "simultaneous"), initial_value="default", ) self.ramping_state_check_interval = Parameter( name="ramping_state_check_interval", instrument=self, initial_value=0.05, unit="s", vals=Numbers(0, 10), set_cmd=None, get_cmd=None, ) self.vector_ramp_rate = Parameter( name="vector_ramp_rate", instrument=self, unit="T/s", vals=Numbers(min_value=0.0), set_cmd=None, get_cmd=None, set_parser=self._set_vector_ramp_rate_units, docstring="Ramp rate along a line (vector) in 3D space. Only active" " if `ramp_mode='simultaneous'`.", ) """Ramp rate along a line (vector) in 3D field space""" self._exit_stack = ExitStack() def _set_vector_ramp_rate_units(self, val: float) -> float: _, common_ramp_rate_units = self._raise_if_not_same_field_and_ramp_rate_units() self.vector_ramp_rate.unit = common_ramp_rate_units return val
[docs] def ramp_simultaneously(self, setpoint: FieldVector, duration: float) -> None: """ Ramp all axes simultaneously to the given setpoint and in the given time The method calculates and sets the required ramp rates per magnet axis, and then initiates a ramp simultaneously on all the axes. The trajectory of the tip of the magnetic field vector is thus linear in 3D space, from the current field value to the setpoint. If ``block_during_ramp`` parameter is ``True``, the method will block until all axes finished ramping. If ``block_during_ramp`` parameter is ``True``, the ramp rates of individual magnet axes will be restored after the end of the ramp to their original values before the call of this method. If ``block_during_ramp`` parameter is ``False``, call the ``wait_while_all_axes_ramping`` method when needed to restore the ramp rates of the individual magnet axes. It is required for all axis instruments to have the same units for ramp rate and field, otherwise an exception is raised. The given setpoint and time are assumed to be in those common units. Args: setpoint: ``FieldVector`` setpoint duration: time in which the setpoint field has to be reached on all axes """ ( common_field_units, common_ramp_rate_units, ) = self._raise_if_not_same_field_and_ramp_rate_units() self.log.debug( f"Simultaneous ramp: setpoint {setpoint.repr_cartesian()} " f"{common_field_units} in {duration} {common_ramp_rate_units}" ) # Get starting field value start_field = self._get_measured_field_vector() self.log.debug( f"Simultaneous ramp: start {start_field.repr_cartesian()} " f"{common_field_units}" ) self.log.debug( f"Simultaneous ramp: delta {(setpoint - start_field).repr_cartesian()} " f"{common_field_units}" ) # Calculate new vector ramp rate based on time and setpoint vector_ramp_rate = self.calculate_vector_ramp_rate_from_duration( start=start_field, setpoint=setpoint, duration=duration ) self.vector_ramp_rate(vector_ramp_rate) self.log.debug( f"Simultaneous ramp: new vector ramp rate for {self.full_name} " f"is {vector_ramp_rate} {common_ramp_rate_units}" ) # Launch the simultaneous ramp self.ramp_mode("simultaneous") self.cartesian(setpoint.get_components("x", "y", "z"))
[docs] @staticmethod def calculate_axes_ramp_rates_for( start: FieldVector, setpoint: FieldVector, duration: float ) -> Tuple[float, float, float]: """ Given starting and setpoint fields and expected ramp time calculates required ramp rates for x, y, z axes (in this order) where axes are ramped simultaneously. """ vector_ramp_rate = AMI430_3D.calculate_vector_ramp_rate_from_duration( start, setpoint, duration ) return AMI430_3D.calculate_axes_ramp_rates_from_vector_ramp_rate( start, setpoint, vector_ramp_rate )
[docs] @staticmethod def calculate_vector_ramp_rate_from_duration( start: FieldVector, setpoint: FieldVector, duration: float ) -> float: return setpoint.distance(start) / duration
[docs] @staticmethod def calculate_axes_ramp_rates_from_vector_ramp_rate( start: FieldVector, setpoint: FieldVector, vector_ramp_rate: float ) -> Tuple[float, float, float]: delta_field = setpoint - start ramp_rate_3d = delta_field / delta_field.norm() * vector_ramp_rate return abs(ramp_rate_3d["x"]), abs(ramp_rate_3d["y"]), abs(ramp_rate_3d["z"])
def _raise_if_not_same_field_and_ramp_rate_units(self) -> Tuple[str, str]: instruments = (self._instrument_x, self._instrument_y, self._instrument_z) field_units_of_instruments = defaultdict(set) ramp_rate_units_of_instruments = defaultdict(set) for instrument in instruments: ramp_rate_units_of_instruments[instrument.ramp_rate_units.cache.get()].add( instrument.full_name ) field_units_of_instruments[instrument.field_units.cache.get()].add( instrument.full_name ) if len(field_units_of_instruments) != 1: raise ValueError( f"Magnet axes instruments should have the same " f"`field_units`, instead they have: " f"{field_units_of_instruments}" ) if len(ramp_rate_units_of_instruments) != 1: raise ValueError( f"Magnet axes instruments should have the same " f"`ramp_rate_units`, instead they have: " f"{ramp_rate_units_of_instruments}" ) common_field_units = tuple(field_units_of_instruments.keys())[0] common_ramp_rate_units = tuple(ramp_rate_units_of_instruments.keys())[0] return common_field_units, common_ramp_rate_units def _verify_safe_setpoint( self, setpoint_values: Tuple[float, float, float] ) -> bool: if isinstance(self._field_limit, (int, float)): return bool(np.linalg.norm(setpoint_values) < self._field_limit) answer = any( [limit_function(*setpoint_values) for limit_function in self._field_limit] ) return answer def _adjust_child_instruments(self, values: Tuple[float, float, float]) -> None: """ Set the fields of the x/y/z magnets. This function is called whenever the field is changed and performs several safety checks to make sure no limits are exceeded. Args: values: a tuple of cartesian coordinates (x, y, z). """ self.log.debug("Checking whether fields can be set") # Check if exceeding the global field limit if not self._verify_safe_setpoint(values): raise ValueError("_set_fields aborted; field would exceed limit") # Check if the individual instruments are ready for name, value in zip(["x", "y", "z"], values): instrument = getattr(self, f"_instrument_{name}") if instrument.ramping_state() == "ramping": msg = "_set_fields aborted; magnet {} is already ramping" raise AMI430Exception(msg.format(instrument)) # Now that we know we can proceed, call the individual instruments self.log.debug("Field values OK, proceeding") if self.ramp_mode() == "simultaneous": self._perform_simultaneous_ramp(values) else: self._perform_default_ramp(values) def _update_individual_axes_ramp_rates( self, values: Tuple[float, float, float] ) -> None: if self.vector_ramp_rate() is None or self.vector_ramp_rate() == 0: raise ValueError( "The value of the `vector_ramp_rate` Parameter is " "currently None or 0. Set it to an appropriate " "value to use the simultaneous ramping feature." ) new_axes_ramp_rates = self.calculate_axes_ramp_rates_from_vector_ramp_rate( start=self._get_measured_field_vector(), setpoint=FieldVector(x=values[0], y=values[1], z=values[2]), vector_ramp_rate=self.vector_ramp_rate.get(), ) instruments = (self._instrument_x, self._instrument_y, self._instrument_z) for instrument, new_axis_ramp_rate in zip(instruments, new_axes_ramp_rates): instrument.ramp_rate.set(new_axis_ramp_rate) self.log.debug( f"Simultaneous ramp: new rate for {instrument.full_name} " f"is {new_axis_ramp_rate} {instrument.ramp_rate.unit}" ) def _perform_simultaneous_ramp(self, values: Tuple[float, float, float]) -> None: self._prepare_to_restore_individual_axes_ramp_rates() self._update_individual_axes_ramp_rates(values) axes = (self._instrument_x, self._instrument_y, self._instrument_z) for axis_instrument, value in zip(axes, values): current_actual = axis_instrument.field() # If the new set point is practically equal to the # current one then do nothing if np.isclose(value, current_actual, rtol=0, atol=1e-8): self.log.debug( f"Simultaneous ramp: {axis_instrument.short_name} is " f"already at target field {value} " f"{axis_instrument.field.unit} " f"({current_actual} exactly)" ) continue self.log.debug( f"Simultaneous ramp: setting {axis_instrument.short_name} " f"target field to {value} {axis_instrument.field.unit}" ) axis_instrument.set_field(value, perform_safety_check=False, block=False) if self.block_during_ramp() is True: self.log.debug(f"Simultaneous ramp: blocking until ramp is finished") self.wait_while_all_axes_ramping() else: self.log.debug("Simultaneous ramp: not blocking until ramp is finished") self.log.debug(f"Simultaneous ramp: returning from the ramp call") def _perform_default_ramp(self, values: Tuple[float, float, float]) -> None: operators: Tuple[Callable[[Any, Any], bool], ...] = (np.less, np.greater) for operator in operators: # First ramp the coils that are decreasing in field strength. # This will ensure that we are always in a safe region as # far as the quenching of the magnets is concerned for name, value in zip(["x", "y", "z"], values): instrument = getattr(self, f"_instrument_{name}") current_actual = instrument.field() # If the new set point is practically equal to the # current one then do nothing if np.isclose(value, current_actual, rtol=0, atol=1e-8): continue # evaluate if the new set point is smaller or larger # than the current value if not operator(abs(value), abs(current_actual)): continue instrument.set_field( value, perform_safety_check=False, block=self.block_during_ramp.get(), ) def _prepare_to_restore_individual_axes_ramp_rates(self) -> None: for instrument in (self._instrument_x, self._instrument_y, self._instrument_z): self._exit_stack.enter_context(instrument.ramp_rate.restore_at_exit()) self._exit_stack.callback( self.log.debug, "Restoring individual axes ramp rates", )
[docs] def wait_while_all_axes_ramping(self) -> None: """ Wait and blocks as long as any magnet axis is ramping. After the ramping is finished, also resets the individual ramp rates of the magnet axes if those were made to be restored, e.g. by using ``simultaneous`` ramp mode. """ while self.any_axis_is_ramping(): self._instrument_x._sleep(self.ramping_state_check_interval.get()) self._exit_stack.close()
[docs] def any_axis_is_ramping(self) -> bool: """ Returns True if any of the magnet axes are currently ramping, or False if none of the axes are ramping. """ return any( axis_instrument.ramping_state() == "ramping" for axis_instrument in ( self._instrument_x, self._instrument_y, self._instrument_z, ) )
[docs] def pause(self) -> None: """Pause all magnet axes.""" for axis_instrument in ( self._instrument_x, self._instrument_y, self._instrument_z, ): axis_instrument.pause()
def _request_field_change(self, instrument: AMI430, value: numbers.Real) -> None: """ This method is called by the child x/y/z magnets if they are set individually. It results in additional safety checks being performed by this 3D driver. """ if instrument is self._instrument_x: self._set_x(value) elif instrument is self._instrument_y: self._set_y(value) elif instrument is self._instrument_z: self._set_z(value) else: msg = "This magnet doesnt belong to its specified parent {}" raise NameError(msg.format(self)) def _get_measured_field_vector(self) -> FieldVector: return FieldVector( x=self._instrument_x.field(), y=self._instrument_y.field(), z=self._instrument_z.field(), ) def _get_measured(self, *names: str) -> Union[numbers.Real, List[numbers.Real]]: measured_field_vector = self._get_measured_field_vector() measured_values = measured_field_vector.get_components(*names) # Convert angles from radians to degrees d = dict(zip(names, measured_values)) # Do not do "return list(d.values())", because then there is # no guaranty that the order in which the values are returned # is the same as the original intention return_value = [d[name] for name in names] if len(names) == 1: return_value = return_value[0] return return_value def _get_setpoints( self, names: Sequence[str] ) -> Union[numbers.Real, List[numbers.Real]]: measured_values = self._set_point.get_components(*names) # Convert angles from radians to degrees d = dict(zip(names, measured_values)) return_value = [d[name] for name in names] # Do not do "return list(d.values())", because then there is # no guarantee that the order in which the values are returned # is the same as the original intention if len(names) == 1: return_value = return_value[0] return return_value def _set_setpoints(self, names: Sequence[str], values: Sequence[float]) -> None: kwargs = dict(zip(names, np.atleast_1d(values))) set_point = FieldVector() set_point.copy(self._set_point) if len(kwargs) == 3: set_point.set_vector(**kwargs) else: set_point.set_component(**kwargs) self._adjust_child_instruments(set_point.get_components("x", "y", "z")) self._set_point = set_point