csaxs_bec.devices.epics.specMotors.MonoTheta2#

class MonoTheta2(read_pv, *, string=False, name=None, **kwargs)[source]#

Bases: VirtualEpicsSignalRO

Converts the pusher motor position to theta angle

Methods

`add_instantiation_callback`	Register a callback which will receive each OphydObject instance.
`calc`
`check_value`	Check if the value is valid for this object
`clear_sub`	Remove a subscription, given the original callback function
`describe`	Return the description as a dictionary
`describe_configuration`	Provide schema & meta-data for `BlueskyInterface.read_configuration()`
`destroy`	Disconnect the Signal from the underlying control layer; destroy it
`get`	Get the readback value through an explicit call to EPICS.
`put`	Disabled for a read-only signal
`read`	Put the status of the signal into a simple dictionary format for data acquisition
`read_configuration`	Dictionary mapping names to value dicts with keys: value, timestamp
`set`	Disabled for a read-only signal
`set_default_timeout`
`set_defaults`	Set class-wide defaults for EPICS CA communications
`subscribe`	Subscribe to events this event_type generates.
`trigger`	Call that is used by bluesky prior to read()
`unsubscribe`	Remove a subscription
`unsubscribe_all`
`wait_for_connection`	Wait for the underlying signals to initialize or connect

Attributes

`SUB_META`
`SUB_VALUE`
`alarm_severity`	PV alarm severity
`alarm_status`	PV status
`as_string`	Attempt to cast the EPICS PV value to a string by default
`attr_name`
`connected`	Is the signal connected to its associated hardware, and ready to use?
`connection_timeout`
`dotted_name`	Return the dotted name
`enum_strs`	List of strings if PV is an enum type
`event_types`	Events that can be subscribed to via `obj.subscribe`
`high_limit`	The high, inclusive control limit for the Signal
`hints`	Field hints for plotting
`kind`
`limits`	The PV control limits (low, high), such that low <= value <= high
`low_limit`	The low, inclusive control limit for the Signal
`metadata`	A copy of the metadata dictionary associated with the signal
`metadata_keys`	Metadata keys that will be passed along on value subscriptions
`name`	name of the device
`parent`	The parent of the ophyd object.
`precision`	The precision of the read PV, as reported by EPICS
`pvname`	The readback PV name
`read_access`	Can the signal be read?
`report`	A report on the object.
`root`	Walk parents to find ultimate ancestor (parent's parent...).
`source_name`
`subscriptions`
`timeout`
`timestamp`	Timestamp of readback PV, according to EPICS
`tolerance`	The absolute tolerance associated with the value.
`value`	The signal's value
`write_access`	Can the signal be written to?
`write_timeout`

classmethod add_instantiation_callback(callback, fail_if_late=False)#

Register a callback which will receive each OphydObject instance.

Parameters:

callback (callable) – Expected signature: f(ophydobj_instance)
fail_if_late (boolean) – If True, verify that OphydObj has not yet been instantiated and raise RuntimeError if it has, as a way of verify that no instances will be “missed” by this registry. False by default.

property alarm_severity#: PV alarm severity

property alarm_status#: PV status

property as_string#: Attempt to cast the EPICS PV value to a string by default

check_value(value, **kwargs)#

Check if the value is valid for this object

This function does no normalization, but may raise if the value is invalid.

Raises:: ValueError –

clear_sub(cb, event_type=None)#

Remove a subscription, given the original callback function

See also subscribe(), unsubscribe()

Parameters:

cb (callable) – The callback
event_type (str, optional) – The event to unsubscribe from (if None, removes it from all event types)

property connected#: Is the signal connected to its associated hardware, and ready to use?

describe()#

Return the description as a dictionary

Returns:: Dictionary of name and formatted description string
Return type:: dict

describe_configuration()#

Provide schema & meta-data for BlueskyInterface.read_configuration()

This keys in the OrderedDict this method returns must match the keys in the OrderedDict return by read().

This provides schema related information, (ex shape, dtype), the source (ex PV name), and if available, units, limits, precision etc.

Returns:: data_keys – The keys must be strings and the values must be dict-like with the event_model.event_descriptor.data_key schema.
Return type:: OrderedDict

destroy()#

Disconnect the Signal from the underlying control layer; destroy it

Clears all subscriptions on this Signal. Once destroyed, the signal may no longer be used.

property dotted_name: str#: Return the dotted name

property enum_strs#: List of strings if PV is an enum type

property event_types#: Events that can be subscribed to via obj.subscribe

get(*args, **kwargs)#

Get the readback value through an explicit call to EPICS.

Parameters:

count (int, optional) – Explicitly limit count for array data
as_string (bool, optional) – Get a string representation of the value, defaults to as_string from this signal, optional
as_numpy (bool) – Use numpy array as the return type for array data.
timeout (float, optional) – maximum time to wait for value to be received. (default = 0.5 + log10(count) seconds)
use_monitor (bool, optional) – to use value from latest monitor callback or to make an explicit CA call for the value. (default: True)
connection_timeout (float, optional) – If not already connected, allow up to connection_timeout seconds for the connection to complete.
form ({'time', 'ctrl'}) – PV form to request

property high_limit#: The high, inclusive control limit for the Signal

property hints#: Field hints for plotting

property limits#: The PV control limits (low, high), such that low <= value <= high

property low_limit#: The low, inclusive control limit for the Signal

property metadata#: A copy of the metadata dictionary associated with the signal

property metadata_keys#: Metadata keys that will be passed along on value subscriptions

property name#: name of the device

property parent#

The parent of the ophyd object.

If at the top of its hierarchy, parent will be None

property precision#: The precision of the read PV, as reported by EPICS

put(*args, **kwargs)#: Disabled for a read-only signal

property pvname#: The readback PV name

read()#

Put the status of the signal into a simple dictionary format for data acquisition

Return type:: dict

property read_access#: Can the signal be read?

read_configuration()#: Dictionary mapping names to value dicts with keys: value, timestamp

property report#: A report on the object.

property root#: Walk parents to find ultimate ancestor (parent’s parent…).

set(*args, **kwargs)#: Disabled for a read-only signal

classmethod set_defaults(*, timeout=2.0, connection_timeout=1.0, write_timeout=None, auto_monitor=False)#

Set class-wide defaults for EPICS CA communications

This may be called only before any instances of EpicsSignalBase are made.

This setting applies to the class it is called on and all its subclasses. For example,

>>> EpicsSignalBase.set_defaults(...)

will apply to EpicsSignalRO and EpicsSignal, which are both subclasses of EpicsSignalBase.

but

>>> EpicsSignal.set_defaults(...)

will not apply to EpicsSignalRO.

Parameters:

auto_monitor (bool, optional) – If True, update cached value from EPICS CA monitor callbacks. If False, request new value from EPICS each time get() is called.
connection_timeout (float, optional) – Time (seconds) allocated for establishing a connection with the IOC.
timeout (float, optional) – Total time budget (seconds) for reading, not including connection time.
write_timeout (float, optional) – Time (seconds) allocated for writing, not including connection time. The write_timeout is very different than the connection and read timeouts above. It relates to how long an action takes to complete. Any default value we choose here is likely to cause problems—either by being too short and giving up too early on a lengthy action or being too long and delaying the report of a failure. The default, None, waits forever.

Raises:

RuntimeError – If called after EpicsSignalBase has been instantiated for the first time.

subscribe(callback, event_type=None, run=True)#

Subscribe to events this event_type generates.

The callback will be called as cb(*args, **kwargs) with the values passed to _run_subs with the following additional keys:

sub_type : the string value of the event_type obj : the host object, added if ‘obj’ not already in kwargs

if the key ‘timestamp’ is in kwargs _and_ is None, then it will be replaced with the current time before running the callback.

The *args, **kwargs passed to _run_subs will be cached as shallow copies, be aware of passing in mutable data.

Warning

If the callback raises any exceptions when run they will be silently ignored.

Parameters:

callback (callable) –
A callable function (that takes kwargs) to be run when the event is generated. The expected signature is
```
def cb(*args, obj: OphydObject, sub_type: str, **kwargs) -> None:
```
The exact args/kwargs passed are whatever are passed to _run_subs
event_type (str, optional) –
The name of the event to subscribe to (if None, defaults to the default sub for the instance - obj._default_sub)

This maps to the sub_type kwargs in _run_subs
run (bool, optional) – Run the callback now