client.remote_variable.RemoteVariable

class documentation

class RemoteVariable(RemoteUaObject['RemoteVariableContainer'], UaDataChangeSubscriber):

Constructor: RemoteVariable(name, ua_node, server, parent)

The remote interface for a server-side UaVariable.

Method	`__init__`	Create a new instance. Must be asynchronously initialized with `init()` before use.
Method	`__str__`	Return string representation of this variable.
Async Method	`read_history`	Provide requested (default=all) historic samples of this variable.
Async Method	`read_raw_value`	Read the actual raw value from the remote server.
Async Method	`read_resolved_value`	Read the resolved value of this variable. Fall back to normal value if there is nothing to resolve.
Async Method	`read_sample`	Read the actual sample from the remote server, not the cached local one.
Async Method	`read_value`	Read the actual value from the remote server, not the cached local one.
Async Method	`ua_on_data_change`	Undocumented
Async Method	`update_from_data_value`	Update the cached sample from given data value or subscription callback data.
Async Method	`write_value`	Try to directly write the given value to the server.
Instance Variable	`children`	Undocumented
Instance Variable	`range`	Range of this variable.
Instance Variable	`unit`	Unit of this variable.
Instance Variable	`value_changed`	Callback when the value or its status changed.
Property	`is_value_node_id`	Return `True` if the value of this RemoteVariable is a not null Node ID.
Property	`is_writable`	Whether this variable is writable or read-only.
Property	`raw_value`	Return the raw value as an OPC UA Variant.
Property	`sample`	Cached sample of this variable: value, status and timestamps.
Property	`timestamp`	Timestamp of the cached sample: source timestamp, falling back to the server timestamp.
Property	`ua_data_type`	Internal OPC UA data type.
Property	`ua_value_rank`	Internal OPC UA value rank (-1 for Scalar, 0 for 1 or more, >=1 exact dimension).
Property	`valid_values`	Valid values of this remote variable in dictionary form.
Property	`value`	Cached Value of this variable.
Async Method	`_init`	Undocumented
Method	`_process_value`	Undocumented
Class Variable	`_data_type_python`	Undocumented
Instance Variable	`_is_writable`	Undocumented
Instance Variable	`_sample`	Undocumented
Instance Variable	`_ua_data_type`	Undocumented
Instance Variable	`_ua_value_rank`	Undocumented
Instance Variable	`_valid_values`	Undocumented

def __init__(self, *, name: str, ua_node: Node, server: RemoteServer, parent: RemoteVariableContainer): ¶

Create a new instance. Must be asynchronously initialized with init() before use.

def __str__(self) -> str: ¶

Return string representation of this variable.

async def read_history(self, start_time: datetime | None = None, end_time: datetime | None = None, num_values: int = 0, return_bounds: bool = True) -> list[Sample[Any]]: ¶

Provide requested (default=all) historic samples of this variable.

Parameters
start_time:`datetime \| None`	Start timestamp in UTC for the first data point of the period if specified.
end_time:`datetime \| None`	End timestamp in UTC for the last data point of the period if specified.
num_values:`int`	Maximum number of values returned. 0 = No maximum.
return_bounds:`bool`	Include the bounding values?

Returns
`list[Sample[Any]]`	Undocumented

async def read_raw_value(self) -> Variant: ¶

Read the actual raw value from the remote server.

async def read_resolved_value(self) -> Any: ¶

Read the resolved value of this variable. Fall back to normal value if there is nothing to resolve.

For example, if this variable value is a node id, resolve it to the display name of the target node. If the display name is not readable, fall back to the browse name. If that is also not readable, return the last part of the string identifier of the node.

async def read_sample(self, *, update_cache: bool = False) -> Sample[Any]: ¶

Read the actual sample from the remote server, not the cached local one.

async def read_value(self, *, update_cache: bool = False) -> Any: ¶

Read the actual value from the remote server, not the cached local one.

@override

async def ua_on_data_change(self, node: Node, val: Any, data: DataChangeNotif): ¶

Undocumented

async def update_from_data_value(self, value: DataValue | DataChangeNotif | None): ¶

Update the cached sample from given data value or subscription callback data.

Sends value_changed only if the value or its status changed, like the OPC UA default data change trigger.

async def write_value(self, value: Any): ¶

Try to directly write the given value to the server.

Might fail if variable is not writable or user has currently no rights to write the variable.

children: dict[str, RemoteVariable] = ¶

Undocumented

range: ua.Range | None = ¶

Range of this variable.

unit: ua.EUInformation | None = ¶

Unit of this variable.

value_changed = ¶

Callback when the value or its status changed.

@property

is_value_node_id: bool = ¶

Return True if the value of this RemoteVariable is a not null Node ID.

@property

is_writable: bool = ¶

Whether this variable is writable or read-only.

Note however, that this is separate from the current access rights of the user.

@property

raw_value: Variant = ¶

Return the raw value as an OPC UA Variant.

@property

sample: Sample[Any] = ¶

Cached sample of this variable: value, status and timestamps.

Has the status BadWaitingForInitialData until the first value was read or received.

@property

timestamp: datetime | None = ¶

Timestamp of the cached sample: source timestamp, falling back to the server timestamp.

@property

ua_data_type: str = ¶

Internal OPC UA data type.

@property

ua_value_rank: int = ¶

Internal OPC UA value rank (-1 for Scalar, 0 for 1 or more, >=1 exact dimension).

@property

valid_values: dict[int, str] | dict[str, str] = ¶

Valid values of this remote variable in dictionary form.

Used for e.g. selection dropdown in front-end.

@property

value: Any = ¶

Cached Value of this variable.

@override

async def _init(self): ¶

Undocumented

def _process_value(self, value: Variant | None) -> Any: ¶

Undocumented

_data_type_python: type | None = ¶

Undocumented

_is_writable: bool = ¶

Undocumented

_sample: Sample[Any] = ¶

Undocumented

_ua_data_type: str = ¶

Undocumented

_ua_value_rank: int = ¶

Undocumented

_valid_values: dict[int, str] | dict[str, str] = ¶

Undocumented