pcdsdevices.valve.VRC

class pcdsdevices.valve.VRC(*args, input_branches=[], output_branches=[], **kwargs)

VRC = Valve with Readback and Control

This is the standard normally-closed valve class. It corresponds with ST_VRC in the lcls-twincat-vacuum library, though it also adds some PVs from ST_ValveBase.

This class does not contain detailed interlocking information, rather it only includes whether or not an interlock is present.

Ophyd Device Components

Attribute	Class	Suffix	Docs	Kind	Notes
lightpath_summary	SummarySignal			omitted	Inherited from LightpathMixin
valve_position	EpicsSignalRO	:POS_STATE_RBV	Ex: OPEN, CLOSED, MOVING, INVALID, OPEN_F	hinted	Inherited from VVC
open_command	EpicsSignalWithRBV	:OPN_SW	Epics command to Open valve	normal	Inherited from VVC
interlock_ok	EpicsSignalRO	:OPN_OK_RBV	Valve is OK to Open interlock	normal	Inherited from VVC
open_do	EpicsSignalRO	:OPN_DO_RBV	PLC Output to Open valve, 1 means 24V on command cable	normal	Inherited from VVC
error_reset	EpicsSignalWithRBV	:ALM_RST	Reset Error state to valid by toggling this	normal	Inherited from VVC
override_status	EpicsSignalRO	:OVRD_ON_RBV	Epics Readback on Override mode	omitted	Inherited from VVC
override_force_open	EpicsSignalWithRBV	:FORCE_OPN	Epics Command to force open the valve inoverride mode	omitted	Inherited from VVC
state	EpicsSignalRO	:STATE_RBV	Valve state	normal
open_limit	EpicsSignalRO	:OPN_DI_RBV	Open limit switch digital input	hinted
closed_limit	EpicsSignalRO	:CLS_DI_RBV	Closed limit switch digital input	hinted

Methods

calc_lightpath_state(open_limit: int, closed_limit: int) → LightpathState

Callback for updating inserted/removed for lightpath.

configure(d: Dict[str, Any]) → Tuple[Dict[str, Any], Dict[str, Any]]

Configure the device for something during a run

This default implementation allows the user to change any of the configuration_attrs. Subclasses might override this to perform additional input validation, cleanup, etc.

Parameters:

d (dict) – The configuration dictionary. To specify the order that the changes should be made, use an OrderedDict.

Returns:

• (old, new) tuple of dictionaries

• Where old and new are pre- and post-configure configuration states.

describe() → OrderedDictType[str, Dict[str, Any]]

Provide schema and meta-data for read().

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 (OrderedDict) – The keys must be strings and the values must be dict-like with the event_model.event_descriptor.data_key schema.

get(**kwargs)

Get the value of all components in the device

Keyword arguments are passed onto each signal.get(). Components beginning with an underscore will not be included.

get_lightpath_state(use_cache: bool = True) → LightpathState

Return the current LightpathState

Returns:

LightpathState – a dataclass containing the Lightpath state

read() → OrderedDictType[str, Dict[str, Any]]

Read data from the device.

This method is expected to be as instantaneous as possible, with any substantial acquisition time taken care of in trigger().

The OrderedDict returned by this method must have identical keys (in the same order) as the OrderedDict returned by describe().

By convention, the first key in the return is the ‘primary’ key and maybe used by heuristics in bluesky.

The values in the ordered dictionary must be dict (-likes) with the keys {'value', 'timestamp'}. The 'value' may have any type, the timestamp must be a float UNIX epoch timestamp in UTC.

Returns:

data (OrderedDict) – The keys must be strings and the values must be dict-like with the keys {'value', 'timestamp'}

read_configuration() → OrderedDictType[str, Dict[str, Any]]

Dictionary mapping names to value dicts with keys: value, timestamp

To control which fields are included, change the Component kinds on the device, or modify the configuration_attrs list.

stop(*, success=False)

Stop the Device and all (instantiated) subdevices

summary()

trigger() → StatusBase

Trigger the device and return status object.

This method is responsible for implementing ‘trigger’ or ‘acquire’ functionality of this device.

If there is an appreciable time between triggering the device and it being able to be read (via the read() method) then this method is also responsible for arranging that the StatusBase object returned by this method is notified when the device is ready to be read.

If there is no delay between triggering and being readable, then this method must return a StatusBase object which is already completed.

Returns:

status (StatusBase) – StatusBase object which will be marked as complete when the device is ready to be read.

Attributes

configuration_attrs

connected

hints

kind

lightpath_cpts = ['open_limit', 'closed_limit']

md

subscriptions: ClassVar[FrozenSet[str]] = frozenset({'acq_done'})