pcdsdevices.state.TwinCATStatePositioner

class pcdsdevices.state.TwinCATStatePositioner(prefix, *, name, **kwargs)

A StatePositioner from Beckhoff land.

This comes from the state record PVs included in the lcls-twincat-motion TwinCAT library. It can be used for any function block that follows the pattern set up by FB_EpicsInOut.

Use TwinCATInOutPositioner instead if the device has clear inserted and removed states.

Does not need to be subclassed to be used, unless you would like to customize the number of states by adjusting config’s state_count. See Example3DStates in example.py for an example on how to adjust the state_count and motor_count.

states_list does not have to be provided in a subclass.

Parameters:

• prefix (str) – The EPICS PV prefix for this motor.

• name (str) – An identifying name for this motor.

• settle_time (float, optional) – The amount of extra time to wait before interpreting a move as done.

• timeout (float, optional) – The amount of time to wait before automatically marking a long in-progress move as failed.

Ophyd Device Components

Attribute	Class	Suffix	Docs	Kind	Notes
state	EpicsSignalEditMD	:GET_RBV	Setpoint and readback for TwinCAT state position.	hinted
error	PytmcSignal	:ERR	True if we have an error.	normal
error_id	PytmcSignal	:ERRID	Error code.	normal
error_message	PytmcSignal	:ERRMSG	Error message	normal
busy	PytmcSignal	:BUSY	True if we have an ongoing move.	normal
done	PytmcSignal	:DONE	True if we completed the last move.	normal
reset_cmd	PytmcSignal	:RESET	Command to reset an error.	normal
config	TwinCATStateConfigDynamic		Configuration of state positions, deltas, etc.	omitted
state_velo	MultiDerivedSignal		State mover velocity. Displays the highest velocity of all the state move destinations and allows bulk writes to all of these velocity settings. Note that this velocity only applies to moves done using the state selector box.	config

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.

clear_error()

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.

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_state(value)

Given an integer or string value, return the proper state entry.

Returns:

state (~enum.Enum) – The corresponding Enum entry for this value. It has two meaningful fields, name and value.

move(position, moved_cb=None, timeout=None, wait=False)

Move to the desired state and return completion information.

Parameters:

• position (int or str) – The enumerate state or the corresponding integer.

• moved_cb (callable, optional) – Function to call at the end of motion. i.e. moved_cb(obj=self) will be called when move is complete.

• timeout (int or float, optional) – Move timeout in seconds.

• wait (bool, optional) – If True, do not return until the motion has completed.

Returns:

status (StateStatus) – Status object that represents the move’s progress.

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.

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, moved_cb=None, timeout=None)

Move to the desired state and return completion information.

This is the bare-bones implementation of the move with only motion, callbacks, and timeouts defined. Additional functional options are relegated to the move command and bells and whistles are relegated to a different interface.

Parameters:

• position (int or str) – The enumerate state or the corresponding integer.

• moved_cb (callable, optional) – Function to call at the end of motion. i.e. moved_cb(obj=self) will be called when move is complete.

• timeout (int or float, optional) – Move timeout in seconds.

Returns:

status (StateStatus) – Status object that represents the move’s progress.

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.

status() → str

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

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.

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

configuration_attrs

connected

connection_timeout

egu = 'state'

high_limit

hints

kind

limits

low_limit

moving

Whether or not the motor is moving

Returns:

moving (bool)

position

Name of the positioner’s current state. If aliases were provided, the first alias will be used instead of the base name.

settle_time

Amount of time to wait after moves to report status completion

states_list = []

stop

Hide the stop method behind an AttributeError.

This makes it so that other interfaces know that the stop method can’t be run without needing to run it to find out.

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

timeout

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