pcdsdevices.mps.MPSLimits

class pcdsdevices.mps.MPSLimits(prefix, logic, **kwargs)

Logical combination of two MPS bits.

The MPSLimits class is to determine what action is to be taken based on the MPS values of a device pertaining to a single device. If a device has two MPS values, there is certain logic that needs to be followed to determine whether or not the beam is allowed through.

Parameters:

• prefix (str) – Base of the MPS PVs.

• name (str) – Name of the MPS combination.

• logic (callable) –

  Determine whether the MPS is faulted based on the state of each limit. The function signature should look like:

  def logic(in_limit: bool, out_limit: bool) -> bool
  

Ophyd Device Components

Attribute	Class	Suffix	Docs	Kind	Notes
in_limit	MPS	_IN		normal
out_limit	MPS	_OUT		normal

Methods

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.

post_elog_status()

Post device status to the primary elog, if possible.

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.

screen()

Open a screen for controlling the device.

Default behavior is the typhos screen, but this method can be overridden for more specialized screens.

status() → str

Returns a str with the current pv values for the device.

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

SUB_FAULT_CH = 'sub_mps_faulted'

bypassed

Whether either limit is bypassed.

configuration_attrs

connected

faulted

This property determines whether the two MPS values are faulted and applies a logic function depending on the states of mps_A and mps_B.

hints

kind

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

tripped

Whether this will trip the MPS system.

This is based off of both the faulted state as well as any temporary bypasses on the MPS bit.