pcdsdevices.crix_motion.QuadraticBeckhoffMotor

class pcdsdevices.crix_motion.QuadraticBeckhoffMotor(prefix: str, *, name: str, ca: float, cb: float, cc: float, pol: int, limits: tuple[float, float], **kwargs)

Pseudomotor of the form calc = ax^2 + bx + c.

This represents a linear BeckhoffAxis that turns a crystal. The translation from linear (mm) motion to angular (mrad) motion can be approximated well by a best-fit polynomial of degree 2.

Parameters:

  • prefix (str) – The motor record prefix of the underlying real BeckhoffAxis.

  • name (str, required keyword) – The name of the device to use as a reference.

  • ca (float, required keyword) – The “a” constant in the best-fit polynomial.

  • cb (float, required keyword) – The “b” constant in the best-fit polynomial.

  • cc (float, required keyword) – The “c” constant in the best-fit polynomial.

  • pol (-1 or 1, required keyword) – The polarity of the best-fit curve when converting back from calculated position to real position for requesting a move. The inverse of a quadratic function has two solutions at most points, so we need to pick which one is correct.

  • limits (tuple of floats, required keyword) – The limits to enforce on moves of the calculated axis. This should be a tuple of size 2.

Ophyd Device Components

Attribute

Class

Suffix

Docs

Kind

Notes

calc

PseudoSingleInterface

hinted

real

BeckhoffAxis

omitted

user_readback

InternalSignal

omitted

user_setpoint

InternalSignal

omitted

high_limit_travel

InternalSignal

omitted

low_limit_travel

InternalSignal

omitted

Methods

camonitor()

Shows a live-updating motor position in the terminal.

This will be the value that is returned by the position attribute.

This method ends cleanly at a ctrl+c or after a call to end_monitor_thread(), which may be useful when this is called in a background thread.

check_single(pseudo_single, single_pos)

Check if a new position for a single pseudo positioner is valid

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.

end_monitor_thread()

Stop a camonitor() or wm_update() that is running in another thread.

forward(pseudo_pos: NamedTuple) → NamedTuple

Calculate the position of the motor in mm given the mrad angle.

This is called when we request a move and when we check if the position requested is within the limits of the linear motor.

Note: it is possible for this to come up with a “nan” value if the input falls outside the bounds and gives us a negative in the sqrt function. However, during normal use, we can rely on the pseudo limits to keep us within the range that this calculation is valid and non-nan.

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.

inverse(real_pos: NamedTuple) → NamedTuple

Calculate the position of the crystal in mrad given the mm position.

This is called when we check the current position of the PseudoPositioner.

move(*args, **kwargs)

Move to a specified position, optionally waiting for motion to complete.

Parameters:

  • position – Pseudo 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:
move_single(pseudo, position, **kwargs)

Move one PseudoSingle axis to a position

All other positioners will use their current setpoint/target value, if available. Failing that, their current readback value will be used (see PseudoSingle.sync and PseudoSingle.target).

Parameters:

  • pseudo (PseudoSingle) – PseudoSingle positioner to move

  • position (float) – Position only for the PseudoSingle

  • kwargs (dict) – Passed onto move

mv(position, timeout=None, wait=False, log=True)

Absolute move to a position.

Parameters:

  • position – Desired end position.

  • timeout (float, optional) – If provided, the mover will throw an error if motion takes longer than timeout to complete. If omitted, the mover’s default timeout will be use.

  • wait (bool, optional) – If True, wait for motion completion before returning. Defaults to False.

  • log (bool, optional) – If True, logs the move at INFO level.

mv_ginput(timeout=None)

Moves to a location the user clicks on.

If there are existing plots, this will be the position on the most recently active plot. If there are no existing plots, an empty plot will be created with the motor’s limits as the range.

mvr(delta, timeout=None, wait=False, log=True)

Relative move from this position.

Parameters:

  • delta (float) – Desired change in position.

  • timeout (float, optional) – If provided, the mover will throw an error if motion takes longer than timeout to complete. If omitted, the mover’s default timeout will be use.

  • wait (bool, optional) – If True, wait for motion completion before returning. Defaults to False.

  • log (bool, optional) – If True, logs the move at INFO level.

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.

set(position, **kwargs)

Move to a new position asynchronously

Parameters:

position (PseudoPosition) – Position for the all of the pseudo axes

Returns:

status (MoveStatus)

set_current_position(position)

Adjust all offsets so that the pseudo position matches the input.

This will raise an AttributeError if any of the real motors is missing a set_current_position method.

Parameters:

position (PseudoPos) – The position

set_position(position)

Alias for set_current_position.

Will fail if the motor does not have set_current_position.

status() → str

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

stop(success=False)

Stop the Device and all (instantiated) subdevices

summary()
to_pseudo_tuple(*args, **kwargs)

Convert arguments to a PseudoPosition namedtuple and kwargs

to_real_tuple(*args, **kwargs)

Convert arguments to a RealPosition namedtuple and kwargs

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.

tweak(scale=0.1)

Control this motor using the arrow keys.

Use left arrow to step negative and right arrow to step positive. Use up arrow to increase step size and down arrow to decrease step size. Press q or ctrl+c to quit.

Parameters:

scale (float) – starting step size, default = 0.1

umv(position, timeout=None, log=True, newline=True)

Move to a position, wait, and update with a progress bar.

Parameters:

  • position (float) – Desired end position.

  • timeout (float, optional) – If provided, the mover will throw an error if motion takes longer than timeout to complete. If omitted, the mover’s default timeout will be use.

  • log (bool, optional) – If True, logs the move at INFO level.

  • newline (bool, optional) – If True, inserts a newline after the updates.

umvr(delta, timeout=None, log=True, newline=True)

Relative move from this position, wait, and update with a progress bar.

Parameters:

  • delta (float) – Desired change in position.

  • timeout (float, optional) – If provided, the mover will throw an error if motion takes longer than timeout to complete. If omitted, the mover’s default timeout will be use.

  • log (bool, optional) – If True, logs the move at INFO level.

  • newline (bool, optional) – If True, inserts a newline after the updates.

wait(timeout=None)
wm()

Get the mover’s current positon (where motor).

wm_update()

Shows a live-updating motor position in the terminal.

This will be the value that is returned by the position attribute.

This method ends cleanly at a ctrl+c or after a call to end_monitor_thread(), which may be useful when this is called in a background thread.

Attributes

composite_egu

The composite engineering units (EGU) from all PseudoSingles

concurrent

If concurrent is set, motors will move concurrently (in parallel)

configuration_attrs
connected
egu

The engineering units (EGU) for positions

high_limit

All PseudoSingle high limits as a namedtuple

hints
kind
limits

All PseudoSingle limits as a namedtuple

low_limit

All PseudoSingle low limits as a namedtuple

moving
position

Pseudo motor position namedtuple

pseudo_positioners

Pseudo positioners instances in a namedtuple

Returns:

positioner_instances (PseudoPosition)

real_position

Real motor position namedtuple

real_positioners

Real positioners instances in a namedtuple

Returns:

positioner_instances (RealPosition)

sequential

If sequential is set, motors will move in the sequence they were defined in (i.e., in series)

settle_time

Amount of time to wait after moves to report status completion

subscriptions: ClassVar[FrozenSet[str]] = frozenset({'_req_done', 'acq_done', 'done_moving', 'readback', 'start_moving'})
target

Last commanded target positions

timeout

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