esphome-docs/components/sensor/bl0942.rst

125 lines
5.7 KiB
ReStructuredText

Belling BL0942 Energy Monitor
=============================
.. seo::
:description: Instructions for setting up BL0942 power monitors.
:image: bl0942.png
:keywords: BL0942, Aubess, Mini Smart Switch With Energy Monitor
The ``bl0942`` sensor platform allows you to use BL0942 energy monitors sensors with
ESPHome. These are used in some Tuya-devices (e.g. Aubess Tuya WiFi Mini Smart Switch With Energy Monitor)
The communication with this component is done via a :ref:`UART <uart>`.
You must therefore have a ``uart:`` entry in your configuration with both the TX and RX pins set
to some pins on your board and the baud rate set to 4800 with 1 stop bit.
.. code-block:: yaml
# Example configuration entry
sensor:
- platform: bl0942
voltage:
name: 'BL0942 Voltage'
current:
name: 'BL0942 Current'
power:
name: 'BL0942 Power'
energy:
name: 'BL0942 Energy'
frequency:
name: "BL0942 Frequency"
Configuration variables:
------------------------
- **voltage** (*Optional*): The voltage value of the sensor in Volts.
All options from :ref:`Sensor <config-sensor>`.
- **current** (*Optional*): The current value of the sensor in Amperes. All options from
:ref:`Sensor <config-sensor>`.
- **power** (*Optional*): The (active) power value of the sensor in Watts. Note that some power meters will report this in negative values (probably wired backwards), so you may want to use a filter to multiply it by -1. All options from :ref:`Sensor <config-sensor>`.
- **energy** (*Optional*): Use the energy value of the sensor in kWh.
All options from :ref:`Sensor <config-sensor>`.
- **frequency** (*Optional*): The frequency value of the sensor in Hertz. All options from
:ref:`Sensor <config-sensor>`.
All options from :ref:`Sensor <config-sensor>`.
- **update_interval** (*Optional*, :ref:`config-time`): The interval to check the
sensor. Defaults to ``60s``.
- **uart_id** (*Optional*, :ref:`config-id`): Manually specify the ID of the :ref:`UART Component <uart>` if you want
to use multiple UART buses.
- **line_frequency** (*Optional*, string): The nominal AC line frequency of the supply voltage. One of ``50Hz``, ``60Hz``. Defaults to ``50Hz``.
- **address** (*Optional*, int): The address of the BL0942 from its strapping pins. Defaults to ``0``.
- **reset** (*Optional*, boolean): Whether to reset the BL0942 chip on startup, resetting all internal counters. Defaults to ``true``.
- **current_reference** (*Optional*, float): The calibration parameter for current readings. Defaults to ``251213.46469622``.
- **voltage_reference** (*Optional*, float): The calibration parameter for voltage readings. Defaults to ``15873.35944299``.
- **power_reference** (*Optional*, float): The calibration parameter for power readings. Defaults to ``596.0`` unless either ``current_reference`` or ``voltage_reference`` are explicitly set, in which case it is calculated. See :ref:`bl0942-calibration` for more details.
- **energy_reference** (*Optional*, float): The calibration parameter for cumulative energy readings. Defaults to ``3304.61127328`` unless any of ``current_reference``, ``voltage_reference`` or ``power_reference`` are explicitly set, in which case it is calculated. See :ref:`bl0942-calibration` for more details.
.. _bl0942-calibration:
Calibration
-----------
There are two fundamental calibration parameters which are dependent on the hardware: ``voltage_reference`` and ``current_reference``. These can be determined by using an accurate voltage and current meter with a simple resistive load.
The ``power_reference`` value can be derived from those, and will be roughly ``voltage_reference`` * ``current_reference`` * 3537 / (305978 * 73989).
The ``energy_reference`` value can be derived as roughly ``power_reference`` * 3600000 / 419430.4.
For compatibility with existing configurations, if no reference values are set then the original defaults will be used, despite the power and energy calibration not being entirely consistent.
If converting Tuya devices, the factory calibration values can often be obtained from the original firmware. For example, they may be found in DPS parameters 22-25, or the `voltage_coe` and related options.
An example from a Tongou DIN rail power meter unit. The result from ``tinytuya wizard`` included:
.. code-block:: json
{
"code": "voltage_coe",
"value": 15968
},
{
"code": "electric_coe",
"value": 12418
},
{
"code": "power_coe",
"value": 3091
},
{
"code": "electricity_coe",
"value": 2653
},
Noting that the ``electric_coe`` value (DPS 23) should be multiplied by ten, and the ``power_coe`` value should be divided by ten, this results in the following configuration:
.. code-block:: yaml
voltage_reference: 15968 # DPS 21
current_reference: 124180 # DPS 22 * 10
power_reference: 309.1 # DPS 23 / 10
energy_reference: 2653 # DPS 24
Alternatively, the values may be found on the flash of the unit without obtaining
the Tuya keys for local communication. They can be found in the "key value store"
partition. The same device as in the above example had the following (before
flashing ESPHome) at offset ``0x001d5000``:
.. code-block::
001d5000 60 3e 00 00 82 30 00 00 13 0c 00 00 5d 0a 00 00 |`>...0......]...|
The hex values 0x3e60, 0x3082, 0xc13 and 0xa5d seen there correspond to the four
DPS values reported by the running Tuya firmware.
The formulas above for deriving ``power_reference`` and ``energy_reference`` can be
used as a sanity check for the values found from the firmware.
See Also
--------
- :ref:`sensor-filters`
- :apiref:`bl0942/bl0942.h`
- :ghedit:`Edit`