Skip to content

Sensor

The base class for all sensor implementations.

Sensor

Generic sensor instrument configured with valid tags and namespace.

The Sensor class provides a base for all sensor implementations, handling Modbus RTU communication, tag validation, and dispatch to sensor-specific read functions.

Key Feature: Instruments are created on-demand during read/write operations and immediately cleaned up afterward. This prevents serial port conflicts when multiple sensors share the same physical port.

Parameters:

Name Type Description Default
port str

Serial port name (e.g., 'COM3' on Windows, '/dev/ttyUSB0' on Linux).

required
valid_tags List[ReadTag]

List of ReadTag instances that are valid for this sensor.

required
namespace dict

Dispatch namespace dictionary containing the multipledispatch Dispatcher for this sensor's tag-specific read functions.

required
serial_config_tags Set[ReadTag]

Set of tags that configure serial communication (require power cycle).

None
sensor_config_tags Set[ReadTag]

Set of tags that configure sensor behavior (may require power cycle).

None
backend_tag ModbusBackendTag

Backend tag for dispatch (default: MinimalmodbusBackendTag).

None
slave_address int

Modbus slave address (default: 1).

required
baudrate int

Serial baudrate (default: 19200).

required
stopbits Stopbits

Number of stop bits (default: Stopbits.ONE).

required
bytesize int

Number of data bits (default: 8).

required
parity Parity

Parity setting (default: Parity.NONE).

required
modbus_mode ModbusMode

Modbus mode (default: ModbusMode.RTU).

required
timeout float

Serial timeout in seconds (default: 0.5).

required

Attributes:

Name Type Description
serial_config_tags Set[ReadTag]

Tags that configure serial communication settings.

sensor_config_tags Set[ReadTag]

Tags that configure sensor behavior settings.

Notes

Instrument Lifecycle:

Unlike traditional implementations where the instrument is created once in init and persists, this implementation creates the instrument on-demand for each read/write operation:

  1. User calls read() or write()
  2. Instrument is created and configured with correct serial settings
  3. Operation is performed
  4. Instrument is cleaned up and serial port is closed
  5. Port is now available for other sensors

This design allows multiple sensors to share the same serial port without conflicts, even if they have different baudrate/stopbit settings.

Performance Impact:

Creating/destroying the instrument adds ~50-100ms overhead per operation. For typical sensor logging intervals (>1s), this is negligible.

Examples:

Multiple sensors on the same port (no conflicts!):

>>> sensor1 = GMP252(port='/dev/ttyACM0', slave_address=121)
>>> sensor2 = AlphaTRACER(port='/dev/ttyACM0', slave_address=122, baudrate=9600)
>>>
>>> # Both work perfectly - no serial port conflicts
>>> result1 = sensor1.read([CO2])  # Creates instrument, reads, cleans up
>>> result2 = sensor2.read([RADON])  # Creates instrument, reads, cleans up

Use with scheduler (original API unchanged):

>>> logger1 = SensorLogger(sensor=sensor1, tags=[CO2], interval_seconds=10, ...)
>>> logger2 = SensorLogger(sensor=sensor2, tags=[RADON], interval_seconds=600, ...)
>>>
>>> scheduler = LoggerScheduler()
>>> scheduler.add_logger(logger1)
>>> scheduler.add_logger(logger2)
>>> scheduler.run()  # Just works!
Source code in atmospyre/sensors/sensor.py
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
class Sensor:
    """Generic sensor instrument configured with valid tags and namespace.

    The Sensor class provides a base for all sensor implementations,
    handling Modbus RTU communication, tag validation, and dispatch to
    sensor-specific read functions.

    **Key Feature**: Instruments are created on-demand during read/write operations
    and immediately cleaned up afterward. This prevents serial port conflicts when
    multiple sensors share the same physical port.

    Parameters
    ----------
    port : str
        Serial port name (e.g., 'COM3' on Windows, '/dev/ttyUSB0' on Linux).
    valid_tags : List[ReadTag]
        List of ReadTag instances that are valid for this sensor.
    namespace : dict
        Dispatch namespace dictionary containing the multipledispatch Dispatcher
        for this sensor's tag-specific read functions.
    serial_config_tags : Set[ReadTag], optional
        Set of tags that configure serial communication (require power cycle).
    sensor_config_tags : Set[ReadTag], optional
        Set of tags that configure sensor behavior (may require power cycle).
    backend_tag : ModbusBackendTag, optional
        Backend tag for dispatch (default: MinimalmodbusBackendTag).
    slave_address : int, optional
        Modbus slave address (default: 1).
    baudrate : int, optional
        Serial baudrate (default: 19200).
    stopbits : Stopbits, optional
        Number of stop bits (default: Stopbits.ONE).
    bytesize : int, optional
        Number of data bits (default: 8).
    parity : Parity, optional
        Parity setting (default: Parity.NONE).
    modbus_mode : ModbusMode, optional
        Modbus mode (default: ModbusMode.RTU).
    timeout : float, optional
        Serial timeout in seconds (default: 0.5).

    Attributes
    ----------
    serial_config_tags : Set[ReadTag]
        Tags that configure serial communication settings.
    sensor_config_tags : Set[ReadTag]
        Tags that configure sensor behavior settings.

    Notes
    -----
    **Instrument Lifecycle**:

    Unlike traditional implementations where the instrument is created once
    in __init__ and persists, this implementation creates the instrument
    on-demand for each read/write operation:

    1. User calls read() or write()
    2. Instrument is created and configured with correct serial settings
    3. Operation is performed
    4. Instrument is cleaned up and serial port is closed
    5. Port is now available for other sensors

    This design allows multiple sensors to share the same serial port
    without conflicts, even if they have different baudrate/stopbit settings.

    **Performance Impact**:

    Creating/destroying the instrument adds ~50-100ms overhead per operation.
    For typical sensor logging intervals (>1s), this is negligible.

    Examples
    --------
    Multiple sensors on the same port (no conflicts!):

    >>> sensor1 = GMP252(port='/dev/ttyACM0', slave_address=121)
    >>> sensor2 = AlphaTRACER(port='/dev/ttyACM0', slave_address=122, baudrate=9600)
    >>>
    >>> # Both work perfectly - no serial port conflicts
    >>> result1 = sensor1.read([CO2])  # Creates instrument, reads, cleans up
    >>> result2 = sensor2.read([RADON])  # Creates instrument, reads, cleans up

    Use with scheduler (original API unchanged):

    >>> logger1 = SensorLogger(sensor=sensor1, tags=[CO2], interval_seconds=10, ...)
    >>> logger2 = SensorLogger(sensor=sensor2, tags=[RADON], interval_seconds=600, ...)
    >>>
    >>> scheduler = LoggerScheduler()
    >>> scheduler.add_logger(logger1)
    >>> scheduler.add_logger(logger2)
    >>> scheduler.run()  # Just works!
    """

    def __init__(
        self,
        port: str,
        valid_tags: List[ReadTag],
        namespace: dict,
        slave_address: int,
        baudrate: int,
        stopbits: Stopbits,
        bytesize: int,
        parity: Parity,
        modbus_mode: ModbusMode,
        timeout: float,
        serial_config_tags: Set[ReadTag] = None,
        sensor_config_tags: Set[ReadTag] = None,
        backend_tag: ModbusBackendTag | None = None,
    ):
        """Initialize sensor configuration without creating instrument.

        The instrument will be created on-demand during read/write operations.
        """
        # Store configuration for later instrument creation
        self._port = port
        self._slave_address = slave_address
        self._baudrate = baudrate
        self._stopbits = stopbits
        self._bytesize = bytesize
        self._parity = parity
        self._modbus_mode = modbus_mode
        self._timeout = timeout

        # Store sensor metadata
        self._valid_tags = valid_tags
        self._namespace = namespace
        self.serial_config_tags = serial_config_tags if serial_config_tags else set()
        self.sensor_config_tags = sensor_config_tags if sensor_config_tags else set()

        if backend_tag is None:
            backend_tag = self._default_backend_tag()
        self._backend_tag = backend_tag

    def _create_instrument(self) -> Instrument:
        """Create and configure a new instrument instance.

        This method is called internally before each read/write operation.
        The instrument is configured with the serial settings provided during
        initialization.

        Returns
        -------
        Instrument
            Configured minimalmodbus Instrument instance.

        Notes
        -----
        The instrument's serial port will have close_port_after_each_call=True
        set by _setup_instrument, ensuring the port is released after each
        Modbus transaction.
        """
        _create_instrument = modbusbackend_namespace["_create_instrument"]
        instrument = _create_instrument(
            self._port, self._slave_address, self._backend_tag
        )

        _setup_instrument = modbusbackend_namespace["_setup_instrument"]
        _setup_instrument(
            instrument,
            self._baudrate,
            self._stopbits,
            self._bytesize,
            self._parity,
            self._modbus_mode,
            self._timeout,
            self._backend_tag,
        )

        return instrument

    @contextmanager
    def _get_instrument(self):
        """Context manager for instrument lifecycle.

        Handles port management via backend-specific open/close functions.
        For backends with automatic port management (like minimalmodbus with
        close_port_after_each_call=True), these are no-ops. For backends
        requiring manual management, they're essential.
        """
        instrument = self._create_instrument()

        self._open_port(instrument)

        try:
            yield instrument
        finally:
            self._close_port(instrument)

    def _cleanup_instrument(self, instrument: Instrument) -> None:
        """Clean up and close the instrument's serial port.

        This method is called internally after each read/write operation
        to ensure the serial port is properly closed and resources are freed.
        Uses backend dispatch to maintain abstraction.

        Parameters
        ----------
        instrument : Instrument
            The instrument instance to clean up.

        Notes
        -----
        Dispatches to the backend's cleanup function to maintain proper
        abstraction and avoid coupling to specific backend implementations.
        """
        if instrument is not None:
            _cleanup_instrument = modbusbackend_namespace.get("_cleanup_instrument")
            if _cleanup_instrument is not None:
                try:
                    _cleanup_instrument(instrument, self._backend_tag)
                except Exception as e:
                    logger.warning(f"Failed to cleanup instrument: {e}")
        del instrument

    def _open_port(self, instrument: Instrument) -> None:
        """Clean up and close the instrument's serial port.

        This method is called internally after each read/write operation
        to ensure the serial port is properly closed and resources are freed.
        Uses backend dispatch to maintain abstraction.

        Parameters
        ----------
        instrument : Instrument
            The instrument instance to clean up.

        Notes
        -----
        Dispatches to the backend's cleanup function to maintain proper
        abstraction and avoid coupling to specific backend implementations.
        """
        if instrument is not None:
            _open_port = modbusbackend_namespace.get("_open_port")
            if _open_port is not None:
                try:
                    _open_port(instrument, self._backend_tag)
                except Exception as e:
                    logger.warning(f"Failed to cleanup instrument: {e}")

    def _close_port(self, instrument: Instrument) -> None:
        """Clean up and close the instrument's serial port.

        This method is called internally after each read/write operation
        to ensure the serial port is properly closed and resources are freed.
        Uses backend dispatch to maintain abstraction.

        Parameters
        ----------
        instrument : Instrument
            The instrument instance to clean up.

        Notes
        -----
        Dispatches to the backend's cleanup function to maintain proper
        abstraction and avoid coupling to specific backend implementations.
        """
        if instrument is not None:
            _close_port = modbusbackend_namespace.get("_close_port")
            if _close_port is not None:
                try:
                    _close_port(instrument, self._backend_tag)
                except Exception as e:
                    logger.warning(f"Failed to close port: {e}")

    def write(self, settings: dict[ReadTag, Any]) -> None:
        """Write one or more settings using tag dispatch.

        Creates an instrument, performs the write operations, then cleans up.
        The serial port is only held during the actual write operation.

        Parameters
        ----------
        settings : dict[ReadTag, Any]
            Dictionary mapping tag instances to values to write.

        Raises
        ------
        ValueError
            If any tag is not valid for writing.

        Warnings
        --------
        If writing serial configuration tags, a power cycle is required.
        Use get_serial_config_tags() to see which tags require power cycle.

        Examples
        --------
        >>> from atmospyre.sensors.implementations.gmp252 import (
        ...     PRESSURE_COMPENSATION_MODE, CO2_FILTERING_FACTOR
        ... )
        >>> sensor.write({
        ...     PRESSURE_COMPENSATION_MODE: True,
        ...     CO2_FILTERING_FACTOR: 90
        ... })
        >>> # If any serial_config_tags were written, power cycle the sensor

        Multiple sensors on same port (no conflicts):

        >>> sensor1.write({TAG1: value1})  # Creates instrument, writes, cleans up
        >>> sensor2.write({TAG2: value2})  # Creates instrument, writes, cleans up
        """
        # Create instrument for this operation
        with self._get_instrument() as instrument:

            try:
                _write = self._namespace["_write"]

                # Check if any serial config tags are being written
                serial_tags_written = [
                    tag for tag in settings.keys() if tag in self.serial_config_tags
                ]

                for tag, value in settings.items():
                    try:
                        _write(instrument, tag, value, self._backend_tag)
                        time.sleep(1)
                    except Exception as e:
                        logger.error(
                            f"Failed to write {type(tag).__name__}: {e}", exc_info=True
                        )
                        raise

                # Warn user if serial config was changed
                if serial_tags_written:
                    logger.warning(
                        f"Serial configuration tags written: {[type(t).__name__ for t in serial_tags_written]}. "
                        "Power cycle required for changes to take effect."
                    )
                    print("\n⚠️  WARNING: Serial configuration changed!")
                    print("Power cycle the sensor to apply changes.")
                    print(
                        f"Tags written: {', '.join([type(t).__name__ for t in serial_tags_written])}\n"
                    )

            finally:
                # Always cleanup, even if an error occurred
                self._cleanup_instrument(instrument)

    def read(self, tags: Union[ReadTag, List[ReadTag]]) -> dict[ReadTag, Any]:
        """Read one or more measurements using tag dispatch.

        Creates an instrument, performs the read operations, then cleans up.
        The serial port is only held during the actual read operation.

        Parameters
        ----------
        tags : ReadTag or List[ReadTag]
            Single ReadTag instance or list of ReadTag instances to read.
            All tags must be in the sensor's valid tag list.

        Returns
        -------
        dict[ReadTag, Any]
            Dictionary mapping each input tag to its measured value.

        Raises
        ------
        ValueError
            If any tag is not in the sensor's valid tag list.
        SensorReadError
            If reading any tag fails due to communication errors.
            The exception contains the failed tag and original error.

        Examples
        --------
        Single tag read:

        >>> result = sensor.read(CO2)
        >>> print(result[CO2])
        415.2

        Multiple tags:

        >>> result = sensor.read([CO2, MEASURED_TEMPERATURE])
        >>> print(f"CO2: {result[CO2]}, Temp: {result[MEASURED_TEMPERATURE]}")
        CO2: 415.2, Temp: 23.5

        Error handling:

        >>> try:
        ...     result = sensor.read([CO2, MEASURED_TEMPERATURE])
        ... except SensorReadError as e:
        ...     print(f"Failed to read {type(e.tag).__name__}")
        ...     print(f"Reason: {e.original_exception}")

        Multiple sensors on same port:

        >>> sensor1 = GMP252(port='/dev/ttyACM0', slave_address=121)
        >>> sensor2 = AlphaTRACER(port='/dev/ttyACM0', slave_address=122)
        >>> result1 = sensor1.read([CO2])    # No conflict!
        >>> result2 = sensor2.read([RADON])  # No conflict!
        """
        # Normalize input to list
        if isinstance(tags, ReadTag):
            tags = [tags]

        # Validate all tags upfront (before creating instrument)
        for tag in tags:
            if tag not in self._valid_tags:
                raise ValueError(
                    f"Tag {type(tag).__name__} not valid for this sensor. "
                    f"Valid tags: {[type(t).__name__ for t in self._valid_tags]}"
                )

        # Create instrument for this operation
        with self._get_instrument() as instrument:

            try:
                # Get the dispatchers registered at the sensor's namespace
                _read = self._namespace["_read"]

                results = {}
                for tag in tags:
                    try:
                        value = _read(instrument, tag, self._backend_tag)
                        results[tag] = value

                    except Exception as e:
                        logger.error(
                            f"Failed to read {type(tag).__name__}: {e}", exc_info=True
                        )
                        raise SensorReadError(tag, e) from e

                return results

            finally:
                # Always cleanup, even if an error occurred
                self._cleanup_instrument(instrument)

    def get_valid_tags(self) -> List[ReadTag]:
        """Get list of all valid tags for this sensor.

        Returns a copy of the valid tags list to prevent external modification.

        Returns
        -------
        List[ReadTag]
            Copy of the list of valid ReadTag instances for this sensor.

        Examples
        --------
        >>> tags = sensor.get_valid_tags()
        >>> print(f"This sensor supports {len(tags)} measurements")
        This sensor supports 5 measurements
        >>>
        >>> for tag in tags:
        ...     meta = tag.metadata
        ...     print(f"- {type(tag).__name__}: {meta.description} ({meta.unit})")
        - CO2Tag: CO2 concentration (float) (ppm)
        - TemperatureTag: Measurement temperature (°C)
        - StatusTag: General device status (None)
        """
        return self._valid_tags.copy()

    def get_serial_config_tags(self) -> Set[ReadTag]:
        """Get set of tags that configure serial communication.

        Writing to these tags requires a power cycle for changes to take effect.

        Returns
        -------
        Set[ReadTag]
            Set of tags that configure serial communication (Modbus address,
            baudrate, parity, stop bits, etc.)

        Examples
        --------
        >>> serial_tags = sensor.get_serial_config_tags()
        >>> for tag in serial_tags:
        ...     print(f"- {type(tag).__name__}: {tag.metadata.description}")
        - ModbusAddressTag: Modbus address (1-247)
        - SerialSpeedTag: Serial speed (0=4800, 1=9600, ...)
        - SerialParityTag: Serial parity (0=None, 1=Even, 2=Odd)
        - SerialStopBitsTag: Serial stop bits (1-2)
        """
        return self.serial_config_tags.copy()

    def get_sensor_config_tags(self) -> Set[ReadTag]:
        """Get set of tags that configure sensor behavior.

        These tags configure sensor-specific settings like compensation modes,
        filtering factors, etc. Some may require power cycle - check documentation.

        Returns
        -------
        Set[ReadTag]
            Set of tags that configure sensor behavior

        Examples
        --------
        >>> config_tags = sensor.get_sensor_config_tags()
        >>> for tag in config_tags:
        ...     print(f"- {type(tag).__name__}: {tag.metadata.description}")
        - PressureCompensationModeTag: Pressure compensation mode
        - CO2FilteringFactorTag: CO2 filtering factor (0-100)
        """
        return self.sensor_config_tags.copy()

    def _default_backend_tag(self):
        """Get the default Modbus backend tag."""
        from atmospyre.sensors.backends.minimalmodbus import MinimalmodbusBackendTag

        return MinimalmodbusBackendTag()

    def __repr__(self) -> str:
        """Return string representation of the sensor.

        Returns
        -------
        str
            Human-readable representation showing sensor type and configuration.

        Examples
        --------
        >>> sensor = GMP252(port='/dev/ttyACM0', slave_address=121)
        >>> print(sensor)
        GMP252(port='/dev/ttyACM0', address=121, baudrate=19200)
        """
        return (
            f"{self.__class__.__name__}("
            f"port='{self._port}', "
            f"address={self._slave_address}, "
            f"baudrate={self._baudrate})"
        )

Functions

__init__(port, valid_tags, namespace, slave_address, baudrate, stopbits, bytesize, parity, modbus_mode, timeout, serial_config_tags=None, sensor_config_tags=None, backend_tag=None)

Initialize sensor configuration without creating instrument.

The instrument will be created on-demand during read/write operations.

Source code in atmospyre/sensors/sensor.py
def __init__(
    self,
    port: str,
    valid_tags: List[ReadTag],
    namespace: dict,
    slave_address: int,
    baudrate: int,
    stopbits: Stopbits,
    bytesize: int,
    parity: Parity,
    modbus_mode: ModbusMode,
    timeout: float,
    serial_config_tags: Set[ReadTag] = None,
    sensor_config_tags: Set[ReadTag] = None,
    backend_tag: ModbusBackendTag | None = None,
):
    """Initialize sensor configuration without creating instrument.

    The instrument will be created on-demand during read/write operations.
    """
    # Store configuration for later instrument creation
    self._port = port
    self._slave_address = slave_address
    self._baudrate = baudrate
    self._stopbits = stopbits
    self._bytesize = bytesize
    self._parity = parity
    self._modbus_mode = modbus_mode
    self._timeout = timeout

    # Store sensor metadata
    self._valid_tags = valid_tags
    self._namespace = namespace
    self.serial_config_tags = serial_config_tags if serial_config_tags else set()
    self.sensor_config_tags = sensor_config_tags if sensor_config_tags else set()

    if backend_tag is None:
        backend_tag = self._default_backend_tag()
    self._backend_tag = backend_tag

read(tags)

Read one or more measurements using tag dispatch.

Creates an instrument, performs the read operations, then cleans up. The serial port is only held during the actual read operation.

Parameters:

Name Type Description Default
tags ReadTag or List[ReadTag]

Single ReadTag instance or list of ReadTag instances to read. All tags must be in the sensor's valid tag list.

required

Returns:

Type Description
dict[ReadTag, Any]

Dictionary mapping each input tag to its measured value.

Raises:

Type Description
ValueError

If any tag is not in the sensor's valid tag list.

SensorReadError

If reading any tag fails due to communication errors. The exception contains the failed tag and original error.

Examples:

Single tag read:

>>> result = sensor.read(CO2)
>>> print(result[CO2])
415.2

Multiple tags:

>>> result = sensor.read([CO2, MEASURED_TEMPERATURE])
>>> print(f"CO2: {result[CO2]}, Temp: {result[MEASURED_TEMPERATURE]}")
CO2: 415.2, Temp: 23.5

Error handling:

>>> try:
...     result = sensor.read([CO2, MEASURED_TEMPERATURE])
... except SensorReadError as e:
...     print(f"Failed to read {type(e.tag).__name__}")
...     print(f"Reason: {e.original_exception}")

Multiple sensors on same port:

>>> sensor1 = GMP252(port='/dev/ttyACM0', slave_address=121)
>>> sensor2 = AlphaTRACER(port='/dev/ttyACM0', slave_address=122)
>>> result1 = sensor1.read([CO2])    # No conflict!
>>> result2 = sensor2.read([RADON])  # No conflict!
Source code in atmospyre/sensors/sensor.py
def read(self, tags: Union[ReadTag, List[ReadTag]]) -> dict[ReadTag, Any]:
    """Read one or more measurements using tag dispatch.

    Creates an instrument, performs the read operations, then cleans up.
    The serial port is only held during the actual read operation.

    Parameters
    ----------
    tags : ReadTag or List[ReadTag]
        Single ReadTag instance or list of ReadTag instances to read.
        All tags must be in the sensor's valid tag list.

    Returns
    -------
    dict[ReadTag, Any]
        Dictionary mapping each input tag to its measured value.

    Raises
    ------
    ValueError
        If any tag is not in the sensor's valid tag list.
    SensorReadError
        If reading any tag fails due to communication errors.
        The exception contains the failed tag and original error.

    Examples
    --------
    Single tag read:

    >>> result = sensor.read(CO2)
    >>> print(result[CO2])
    415.2

    Multiple tags:

    >>> result = sensor.read([CO2, MEASURED_TEMPERATURE])
    >>> print(f"CO2: {result[CO2]}, Temp: {result[MEASURED_TEMPERATURE]}")
    CO2: 415.2, Temp: 23.5

    Error handling:

    >>> try:
    ...     result = sensor.read([CO2, MEASURED_TEMPERATURE])
    ... except SensorReadError as e:
    ...     print(f"Failed to read {type(e.tag).__name__}")
    ...     print(f"Reason: {e.original_exception}")

    Multiple sensors on same port:

    >>> sensor1 = GMP252(port='/dev/ttyACM0', slave_address=121)
    >>> sensor2 = AlphaTRACER(port='/dev/ttyACM0', slave_address=122)
    >>> result1 = sensor1.read([CO2])    # No conflict!
    >>> result2 = sensor2.read([RADON])  # No conflict!
    """
    # Normalize input to list
    if isinstance(tags, ReadTag):
        tags = [tags]

    # Validate all tags upfront (before creating instrument)
    for tag in tags:
        if tag not in self._valid_tags:
            raise ValueError(
                f"Tag {type(tag).__name__} not valid for this sensor. "
                f"Valid tags: {[type(t).__name__ for t in self._valid_tags]}"
            )

    # Create instrument for this operation
    with self._get_instrument() as instrument:

        try:
            # Get the dispatchers registered at the sensor's namespace
            _read = self._namespace["_read"]

            results = {}
            for tag in tags:
                try:
                    value = _read(instrument, tag, self._backend_tag)
                    results[tag] = value

                except Exception as e:
                    logger.error(
                        f"Failed to read {type(tag).__name__}: {e}", exc_info=True
                    )
                    raise SensorReadError(tag, e) from e

            return results

        finally:
            # Always cleanup, even if an error occurred
            self._cleanup_instrument(instrument)

write(settings)

Write one or more settings using tag dispatch.

Creates an instrument, performs the write operations, then cleans up. The serial port is only held during the actual write operation.

Parameters:

Name Type Description Default
settings dict[ReadTag, Any]

Dictionary mapping tag instances to values to write.

required

Raises:

Type Description
ValueError

If any tag is not valid for writing.

Warnings

If writing serial configuration tags, a power cycle is required. Use get_serial_config_tags() to see which tags require power cycle.

Examples:

>>> from atmospyre.sensors.implementations.gmp252 import (
...     PRESSURE_COMPENSATION_MODE, CO2_FILTERING_FACTOR
... )
>>> sensor.write({
...     PRESSURE_COMPENSATION_MODE: True,
...     CO2_FILTERING_FACTOR: 90
... })
>>> # If any serial_config_tags were written, power cycle the sensor

Multiple sensors on same port (no conflicts):

>>> sensor1.write({TAG1: value1})  # Creates instrument, writes, cleans up
>>> sensor2.write({TAG2: value2})  # Creates instrument, writes, cleans up
Source code in atmospyre/sensors/sensor.py
def write(self, settings: dict[ReadTag, Any]) -> None:
    """Write one or more settings using tag dispatch.

    Creates an instrument, performs the write operations, then cleans up.
    The serial port is only held during the actual write operation.

    Parameters
    ----------
    settings : dict[ReadTag, Any]
        Dictionary mapping tag instances to values to write.

    Raises
    ------
    ValueError
        If any tag is not valid for writing.

    Warnings
    --------
    If writing serial configuration tags, a power cycle is required.
    Use get_serial_config_tags() to see which tags require power cycle.

    Examples
    --------
    >>> from atmospyre.sensors.implementations.gmp252 import (
    ...     PRESSURE_COMPENSATION_MODE, CO2_FILTERING_FACTOR
    ... )
    >>> sensor.write({
    ...     PRESSURE_COMPENSATION_MODE: True,
    ...     CO2_FILTERING_FACTOR: 90
    ... })
    >>> # If any serial_config_tags were written, power cycle the sensor

    Multiple sensors on same port (no conflicts):

    >>> sensor1.write({TAG1: value1})  # Creates instrument, writes, cleans up
    >>> sensor2.write({TAG2: value2})  # Creates instrument, writes, cleans up
    """
    # Create instrument for this operation
    with self._get_instrument() as instrument:

        try:
            _write = self._namespace["_write"]

            # Check if any serial config tags are being written
            serial_tags_written = [
                tag for tag in settings.keys() if tag in self.serial_config_tags
            ]

            for tag, value in settings.items():
                try:
                    _write(instrument, tag, value, self._backend_tag)
                    time.sleep(1)
                except Exception as e:
                    logger.error(
                        f"Failed to write {type(tag).__name__}: {e}", exc_info=True
                    )
                    raise

            # Warn user if serial config was changed
            if serial_tags_written:
                logger.warning(
                    f"Serial configuration tags written: {[type(t).__name__ for t in serial_tags_written]}. "
                    "Power cycle required for changes to take effect."
                )
                print("\n⚠️  WARNING: Serial configuration changed!")
                print("Power cycle the sensor to apply changes.")
                print(
                    f"Tags written: {', '.join([type(t).__name__ for t in serial_tags_written])}\n"
                )

        finally:
            # Always cleanup, even if an error occurred
            self._cleanup_instrument(instrument)

get_valid_tags()

Get list of all valid tags for this sensor.

Returns a copy of the valid tags list to prevent external modification.

Returns:

Type Description
List[ReadTag]

Copy of the list of valid ReadTag instances for this sensor.

Examples:

>>> tags = sensor.get_valid_tags()
>>> print(f"This sensor supports {len(tags)} measurements")
This sensor supports 5 measurements
>>>
>>> for tag in tags:
...     meta = tag.metadata
...     print(f"- {type(tag).__name__}: {meta.description} ({meta.unit})")
- CO2Tag: CO2 concentration (float) (ppm)
- TemperatureTag: Measurement temperature (°C)
- StatusTag: General device status (None)
Source code in atmospyre/sensors/sensor.py
def get_valid_tags(self) -> List[ReadTag]:
    """Get list of all valid tags for this sensor.

    Returns a copy of the valid tags list to prevent external modification.

    Returns
    -------
    List[ReadTag]
        Copy of the list of valid ReadTag instances for this sensor.

    Examples
    --------
    >>> tags = sensor.get_valid_tags()
    >>> print(f"This sensor supports {len(tags)} measurements")
    This sensor supports 5 measurements
    >>>
    >>> for tag in tags:
    ...     meta = tag.metadata
    ...     print(f"- {type(tag).__name__}: {meta.description} ({meta.unit})")
    - CO2Tag: CO2 concentration (float) (ppm)
    - TemperatureTag: Measurement temperature (°C)
    - StatusTag: General device status (None)
    """
    return self._valid_tags.copy()