pcdsdevices.twincat_motor.TwinCATMotorInterface

class pcdsdevices.twincat_motor.TwinCATMotorInterface(prefix='', *, name, kind=None, read_attrs=None, configuration_attrs=None, parent=None, **kwargs)

A standard PVPositioner motor with PCDS interface conventions for TwinCAT axes.

This class wraps a standard positioner device and implements PCDS preferences and interface patterns. It presents all critical motion and configuration PVs found in TwinCAT motors, as well as soft limit, status, and safety/diagnostic methods.

Many methods and their core logic in this class (e.g., limits, move, check_value, limit setter/clearer, stop, status change subscriptions, error filtering) are directly reused or adapted from the legacy EpicsMotorInterface to ensure API and UX consistency across PCDS motor controls. See each method’s docstring for duplication/adaptation notes.

Notes

The PCDS interface preferences and design patterns implemented here are:

Uses the FltMvInterface mixin for name aliases and advanced functionality, such as improved tab completion and convenient move/stop helpers.
Implements all limits and soft limits via EPICS/TwinCAT NC soft limit records/tags (NC:MinPos:Goal, etc.), avoiding the internal limits cached by pyepics, which can become stale.
Provides support for detecting disabled states, with appropriate error raising.
Subscribes to all key status bits (moving, limit switches, homed, power, direction) for robust feedback and event-driven updates.
Post-move error logs are only shown after motions initiated from this client session, not from others—by maintaining _moved_in_session and filtering logs accordingly.
All IOCs differences are handled elsewhere; this interface is IOC-agnostic and can be used with any compliant TwinCAT axis IOC.

Ophyd Device Components
Attribute	Class	Suffix	Kind
setpoint	`PytmcSignal`	`fPosition`	hinted
readback	`PytmcSignal`	`fActPosition`	hinted
done	`PytmcSignal`	`bDone`	normal
actuate	`PytmcSignal`	`bMoveCmd`	normal
stop_signal	`PytmcSignal`	`bHalt`	normal
reset_signal	`PytmcSignal`	`bReset`	normal
velocity	`PytmcSignal`	`fVelocity`	config
acceleration	`PytmcSignal`	`fAcceleration`	config
deceleration	`PytmcSignal`	`fDeceleration`	config
jerk	`PytmcSignal`	`fJerk`	config
enable_mode	`PytmcSignal`	`eEnableMode`	config
brake_mode	`PytmcSignal`	`eBrakeMode`	config
motor_is_moving	`PytmcSignal`	`bMoving`	normal
motor_is_moving_negative	`PytmcSignal`	`bNegativeDirection`	normal
motor_is_moving_positive	`PytmcSignal`	`bPositiveDirection`	normal
power_is_enabled	`PytmcSignal`	`bPowerIsEnabled`	normal
high_limit_switch	`PytmcSignal`	`bLimitFwd`	normal
low_limit_switch	`PytmcSignal`	`bLimitBwd`	normal
negative_dir_enabled	`PytmcSignal`	`bNegativeMotionIsEnabled`	normal
positive_dir_enabled	`PytmcSignal`	`bPositiveMotionIsEnabled`	normal
command	`PytmcSignal`	`eCommand`	normal
motor_egu	`PytmcSignal`	`sEGU`	normal
low_limit_travel	`EpicsSignal`	`NC:MinPos:Val_RBV`	config
high_limit_travel	`EpicsSignal`	`NC:MaxPos:Val_RBV`	config
low_limit_enable	`EpicsSignal`	`NC:SoftPosMinOn:Val_RBV`	config
high_limit_enable	`EpicsSignal`	`NC:SoftPosMaxOn:Val_RBV`	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.

check_limit_switches()

Check the limit switches.

Logic structure reused from EpicsMotorInterface for API consistency. Returns a string summary.

clear_limits()

Set both low and high limits to 0.

Duplicated from EpicsMotorInterface for function and API consistency.

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.

move(position: float, wait: bool = True, **kwargs) → MoveStatus: Reused from EpicsMotorInterface: Sets _moved_in_session True, then calls superclass 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.

reset(*, success=False)

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(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.

set_high_limit(value)

Limit of travel in the positive direction. Adapted from EpicsMotorInterface.

Parameters:: value (float) – High limit value to be set.
Raises:: ValueError – When in motion or position outside of limit.

set_low_limit(value)

Set the low limit. Adapted from EpicsMotorInterface.

Parameters:: value (float) – Limit of travel in the negative direction.
Raises:: ValueError – When in motion or position outside of limit.

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()

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

actuate_value = 1

configuration_attrs

connected

connection_timeout

done_value = 1

egu: The engineering units (EGU) for this motor. Updated via the motor_egu PV.

enabled

returns: * bool – True if power is enabled and either negative or positive direction is enabled. * Explanation * ———– * - Returns True if –

Power is on (power_is_enabled)

At least one direction (negative_dir_enabled OR positive_dir_enabled) is enabled

high_limit

hints

homed: Get the home status of the motor

kind

limits

Override limits property to always return the latest values from the soft limit PVs (low_limit_travel and high_limit_travel).

This ensures no stale/cached values are reported.

low_limit

moving

Whether or not the motor is moving.

Duplicated logic from EpicsMotorInterface for API consistency.

Returns:: moving (bool)

position

The current position of the motor in its engineering units

Returns:: position (float)

put_complete

settle_time: Amount of time to wait after moves to report status completion

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

tolerated_alarm = 0