pcdsdevices.pv_positioner.PVPositionerNoInterrupt

class pcdsdevices.pv_positioner.PVPositionerNoInterrupt(*args, **kwargs)

A PV positioner whose moves cannot be interrupted.

If we try to start a new move before the previous move completes, instead we will get a clear error advising us to wait.

Parameters:

  • prefix (str, optional) – The device prefix used for all sub-positioners. This is optional as it may be desirable to specify full PV names for PVPositioners.

  • limits (2-element sequence, optional) – (low_limit, high_limit)

  • name (str) – The device name

  • egu (str, optional) – The engineering units (EGU) for the position

  • settle_time (float, optional) – The amount of time to wait after moves to report status completion

  • timeout (float, optional) – The default timeout to use for motion requests, in seconds.

setpoint

The setpoint (request) signal

Type:

Signal

readback

The readback PV (e.g., encoder position PV)

Type:

Signal or None

actuate

The actuation PV to set when movement is requested

Type:

Signal or None

actuate_value

The actuation value, sent to the actuate signal when motion is requested

Type:

any, optional

stop_signal

The stop PV to set when motion should be stopped

Type:

Signal or None

stop_value

The value sent to stop_signal when a stop is requested

Type:

any, optional

done

A readback value indicating whether motion is finished

Type:

Signal

done_value

The value that the done pv should be when motion has completed

Type:

any, optional

put_complete

If set, the specified PV should allow for asynchronous put completion to indicate motion has finished. If actuate is specified, it will be used for put completion. Otherwise, the setpoint will be used. See the -c option from caput for more information.

Type:

bool, optional

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.

move(position: float, wait: bool = True, timeout: float | None = None, moved_cb: Callable[[PVPositionerNoInterrupt], None] | None = None)

Move to a specified position, optionally waiting for motion to complete. Unlike the standard move, this will fail with a clear error message when a move is already in progress.

Parameters:

  • position (float) – Position to move to

  • moved_cb (callable) – Call this callback when movement has finished. This callback must accept one keyword argument: ‘obj’ which will be set to this positioner instance.

  • timeout (float, optional) – Maximum time to wait for the motion. If None, the default timeout for this positioner is used.

Returns:

status (MoveStatus)

Raises:

  • TimeoutError – When motion takes longer than timeout

  • ValueError – On invalid positions

  • RuntimeError – If motion fails other than timing out, including when a move is attempted while another move is already in progress.

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.

set(new_position: Any, *, timeout: float = None, moved_cb: Callable = None, wait: bool = False) → StatusBase

Set a value and return a Status object

Parameters:

  • new_position (object) – The input here is whatever the device requires (this should be over-ridden by the implementation. For example a motor would take a float, a shutter the strings {‘Open’, ‘Close’}, and a goineometer (h, k, l) tuples

  • timeout (float, optional) – Maximum time to wait for the motion. If None, the default timeout for this positioner is used.

  • moved_cb (callable, optional) –

    Deprecated

    Call this callback when movement has finished. This callback must accept one keyword argument: ‘obj’ which will be set to this positioner instance.

  • wait (bool, optional) –

    Deprecated

    If the method should block until the Status object reports it is done.

    Defaults to False

Returns:

status (StatusBase) – Status object to indicate when the motion / set is done.

classmethod set_defaults(*, connection_timeout=10.0)

Set class-wide defaults for device communications

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

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

>>> Device.set_defaults(...)

will apply to any Device subclass.

Parameters:

connection_timeout (float, optional) – Time (seconds) allocated for establishing a connection with the IOC.

Raises:

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

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

actuate = None
actuate_value = 1
configuration_attrs
connected
connection_timeout
done = None
done_value = 1
egu

The engineering units (EGU) for a position

high_limit
hints
kind
limits
low_limit
moving

Whether or not the motor is moving

If a done PV is specified, it will be read directly to get the motion status. If not, it determined from the internal state of PVPositioner.

Returns:

bool

position

The current position of the motor in its engineering units

Returns:

position (any)

put_complete
readback = None
setpoint = None
settle_time

Amount of time to wait after moves to report status completion

stop_signal = None
stop_value = 1
subscriptions: ClassVar[FrozenSet[str]] = frozenset({'_req_done', 'acq_done', 'done_moving', 'readback', 'start_moving'})
timeout

Amount of time to wait before to considering a motion as failed