def get_pv_name(self, field, handle):
"""Get PV name for the specified field and handle.
Args:
field (str): The requested field.
handle (str): pytac.RB or pytac.SP.
Returns:
str: The readback or setpoint PV for the specified field.
Raises:
DataSourceException: if there is no data source for this field.
FieldException: if the specified field doesn't exist.
"""
try:
return (self._data_source_manager.get_data_source(
pytac.LIVE).get_device(field).get_pv_name(handle))
except DataSourceException as e:
raise DataSourceException(f"{self}: {e}")
except AttributeError:
raise DataSourceException(
f"Cannot get PV for field {field} on element "
f"{self}, as the device does not have associated PVs.")
except FieldException as e:
raise FieldException(f"{self}: {e}")
def __init__(self, name, cs, enabled=True, rb_pv=None, sp_pv=None):
"""
Args:
name (str): The prefix of EPICS PV for this device.
cs (ControlSystem): The control system object used to get and set
the value of a PV.
enabled (bool-like): Whether the device is enabled. May be a
PvEnabler object.
rb_pv (str): The EPICS readback PV.
sp_pv (str): The EPICS setpoint PV.
Raises:
DataSourceException: if no PVs are provided.
**Methods:**
"""
if rb_pv is None and sp_pv is None:
raise DataSourceException(
f"At least one PV ({pytac.RB} or {pytac.SP}) is "
"required when creating an EpicsDevice."
)
self.name = name
self._cs = cs
self.rb_pv = rb_pv
self.sp_pv = sp_pv
self._enabled = enabled
def set_value(
self,
field,
value,
units=pytac.DEFAULT,
data_source=pytac.DEFAULT,
throw=True,
):
"""Set the value for a field.
This value can be set on the machine or the simulation.
Args:
field (str): The requested field.
value (float): The value to set.
units (str): pytac.ENG or pytac.PHYS.
data_source (str): pytac.LIVE or pytac.SIM.
throw (bool): On failure: if True, raise ControlSystemException: if
False, log a warning.
Raises:
DataSourceException: if arguments are incorrect.
FieldException: if the element does not have the specified field.
"""
try:
self._data_source_manager.set_value(field, value, units,
data_source, throw)
except DataSourceException as e:
raise DataSourceException(f"{self}: {e}")
except FieldException as e:
raise FieldException(f"{self}: {e}")
def set_value(self, value, throw=None):
"""Set the value on the device.
Args:
value (numeric): the value to set.
throw (bool): Irrelevant in this case as a control system is not
used, only supported to conform with the base class.
"""
if self._readonly:
raise DataSourceException("Cannot change value of readonly SimpleDevice")
self.value = value
def get_data_source(self, data_source_type):
"""Get a data source.
Args:
data_source_type (str): the type of the data source being set
pytac.LIVE or pytac.SIM.
Raises:
DataSourceException: if there is no data source on the given field.
"""
try:
return self._data_sources[data_source_type]
except KeyError:
raise DataSourceException(
f"No data source {data_source_type} on manager {self}.")
def get_device(self, field):
"""Get the device for the given field.
A DeviceDataSource must be set before calling this method, this
defaults to pytac.LIVE as that is the only data source that currently
uses devices.
Args:
field (str): The lookup key to find the device on an element.
Returns:
Device: The device on the given field.
Raises:
DataSourceException: if no DeviceDataSource is set.
"""
try:
return self._data_source_manager.get_device(field)
except DataSourceException as e:
raise DataSourceException(f"{self}: {e}.")
def add_device(self, field, device, uc):
"""Add device and unit conversion objects to a given field.
A DeviceDataSource must be set before calling this method, this
defaults to pytac.LIVE as that is the only data source that currently
uses devices.
Args:
field (str): The key to store the unit conversion and device
objects.
device (Device): The device object used for this field.
uc (UnitConv): The unit conversion object used for this field.
Raises:
DataSourceException: if no DeviceDataSource is set.
"""
try:
self._data_source_manager.add_device(field, device, uc)
except DataSourceException as e:
raise DataSourceException(f"{self}: {e}.")
def get_pv_name(self, field, handle):
"""Get the PV name for a specific field, and handle on this lattice.
Args:
field (str): The requested field.
handle (str): pytac.RB or pytac.SP.
Returns:
str: The readback or setpoint PV for the specified field.
"""
try:
return (
self._data_source_manager.get_data_source(pytac.LIVE)
.get_device(field)
.get_pv_name(handle)
)
except AttributeError:
raise DataSourceException(
f"Cannot get PV for field {field} on lattice "
f"{self}, as the device does not have associated PVs."
)
def set_default_data_source(self, data_source_type: str) -> None:
"""Sets the default data source for the lattice and all its elements.
Args:
data_source_type: The default data source to be set across the
entire lattice, pytac.LIVE or pytac.SIM.
Raises:
DataSourceException: if specified default data source is not a
valid data source.
"""
if (data_source_type == pytac.LIVE) or (data_source_type == pytac.SIM):
self._data_source_manager.default_data_source = data_source_type
elems = self.get_elements()
for elem in elems:
elem._data_source_manager.default_data_source = data_source_type
else:
raise DataSourceException(
f"{data_source_type} is not a data source. "
f"Please enter {pytac.LIVE} or {pytac.SIM}."
)
def get_value(
self,
field,
handle=pytac.RB,
units=pytac.DEFAULT,
data_source=pytac.DEFAULT,
throw=True,
):
"""Get the value for a field.
Returns the value of a field on the element. This value is uniquely
identified by a field and a handle. The returned value is either
in engineering or physics units. The data_source flag returns either
real or simulated values.
Args:
field (str): The requested field.
handle (str): pytac.SP or pytac.RB.
units (str): pytac.ENG or pytac.PHYS returned.
data_source (str): pytac.LIVE or pytac.SIM.
throw (bool): On failure: if True, raise ControlSystemException; if
False, return None and log a warning.
Returns:
float: The value of the requested field
Raises:
DataSourceException: if there is no data source on the given field.
FieldException: if the element does not have the specified field.
"""
try:
return self._data_source_manager.get_value(field, handle, units,
data_source, throw)
except DataSourceException as e:
raise DataSourceException(f"{self}: {e}")
except FieldException as e:
raise FieldException(f"{self}: {e}")