Modbus Controller
=================

.. seo::
    :description: Instructions for setting up the ModBUS Controller component.
    :image: modbus.png

The ``modbus_controller`` component creates a RS485 connection to control a ModBUS slave device, letting your ESPHome node to act as a ModBUS master.
You can access the coils and registers from your slave ModBUS device as sensors, switches or various other ESPHome components and present them to your favorite Home Automation system.

.. figure:: /images/modbus.png
    :align: center
    :width: 25%

The ``modbus_controller`` component relies on the :doc:`/components/modbus`.



Hardware setup
--------------
You need an RS485 transceiver module:

.. figure:: /images/rs485.jpg

See `How is this RS485 module working? <https://electronics.stackexchange.com/questions/244425/how-is-this-rs485-module-working>`__ on stackexchange for more details.

The transceiver connects to the UART of the MCU. For ESP32, pin ``16`` to ``TXD`` and pin ``17`` to ``RXD`` are the default ones but any other pins can be used as well. ``3.3V`` to ``VCC`` and naturally ``GND`` to ``GND``.

On the bus side, you need 120 Ohm termination resistors at the ends of the bus cable as per ModBUS standard. Some transceivers have this already solderes onboard, and some slave devices may have them preinstalled with a jumper or a dip switch.

.. note::

    If you are using an ESP8266, serial logging may cause problems reading from UART. For best results, hardware serial is recommended. Software serial may not be able to read all received data if other components spend a lot of time in the ``loop()``.

    For hardware serial only a limited set of pins can be used. Either ``tx_pin: GPIO1`` and ``rx_pin: GPIO3``  or ``tx_pin: GPIO15`` and ``rx_pin: GPIO13``.

    The disadvantage of using the hardware uart is that you can't use serial logging because the serial logs would be sent to the ModBUS device and cause errors.

    Serial logging can be disabled by setting ``baud_rate: 0``.

    See :doc:`logger` for more details

    .. code-block:: yaml

        logger:
            level: <level>
            baud_rate: 0



Configuration variables:
------------------------

- **modbus_id** (*Optional*, :ref:`config-id`): Manually specify the ID of the ``modbus`` hub.

- **address** (**Required**, :ref:`config-id`): The ModBUS address of the slave device

- **command_throttle** (*Optional*, :ref:`config-time`): minimum time in between 2 requests to the device. Default is ``0ms``.
  Some ModBUS slave devices limit the rate of requests from the master, the interval between sending requests can be altered.

- **update_interval** (*Optional*, :ref:`config-time`): The interval that the sensors should be checked.
  Defaults to 60 seconds.

- **offline_skip_updates** (*Optional*, integer): When a slave doesn't respond to a command, it is
  marked as offline, you can specify how many updates will be skipped while it is offline. If using a bus with multiple
  slaves, this avoids waiting for timeouts allowing to read other slaves in the same bus. When the slave
  responds to a command, it'll be marked online again.


Example
-------
The following code creates a ``modbus_controller`` hub talking to a ModBUS device at address ``1`` with ``115200`` bps

ModBUS sensors can be directly defined (inline) under the ``modbus_controller`` hub or as standalone components
Technically there is no difference between the "inline" and the standard definitions approach.

.. code-block:: yaml

    uart:
      id: mod_bus
      tx_pin: 17
      rx_pin: 16
      baud_rate: 115200
      stop_bits: 1

    modbus:
      flow_control_pin: 5
      id: modbus1

    modbus_controller:
      - id: epever
        address: 0x1   ## address of the ModBUS slave device on the bus
        modbus_id: modbus1
        setup_priority: -10

    text_sensor:
      - name: "rtc_clock"
        platform: modbus_controller
        modbus_controller_id: epever
        id: rtc_clock
        internal: true
        register_type: holding
        address: 0x9013    ## address of the register inside the ModBUS slave device
        register_count: 3
        raw_encode: HEXBYTES
        response_size: 6

    switch:
      - platform: modbus_controller
        modbus_controller_id: epever
        id: reset_to_fabric_default
        name: "Reset to Factory Default"
        register_type: coil
        address: 0x15
        bitmask: 1

    sensor:
      - platform: modbus_controller
        modbus_controller_id: epever
        name: "Battery Capacity"
        id: battery_capacity
        register_type: holding
        address: 0x9001
        unit_of_measurement: "AH"
        value_type: U_WORD


Bitmasks
--------

Some devices use decimal values in read registers to show multiple binary states occupying only one register address. To decode them, you can use bitmasks according to the table below. The decimal value corresponding to a bit is always double of the previous one in the row. Multiple bits can be represented in a single register by making a sum of all the values corresponding to the bits.

+------------+------------------+-----------+-----------+ 
| Alarm  bit | Description      | DEC value | HEX value |
+============+==================+===========+===========+ 
| bit 0      | Binary Sensor 0  | 1         | 1         |
+------------+------------------+-----------+-----------+ 
| bit 1      | Binary Sensor 1  | 2         | 2         |
+------------+------------------+-----------+-----------+ 
| bit 2      | Binary Sensor 2  | 4         | 4         |
+------------+------------------+-----------+-----------+ 
| bit 3      | Binary Sensor 3  | 8         | 8         |
+------------+------------------+-----------+-----------+ 
| bit 4      | Binary Sensor 4  | 16        | 10        |
+------------+------------------+-----------+-----------+ 
| bit 5      | Binary Sensor 5  | 32        | 20        |
+------------+------------------+-----------+-----------+ 
| bit 6      | Binary Sensor 6  | 64        | 40        |
+------------+------------------+-----------+-----------+ 
| bit 7      | Binary Sensor 7  | 128       | 80        |
+------------+------------------+-----------+-----------+ 
| bit 8      | Binary Sensor 8  | 256       | 100       |
+------------+------------------+-----------+-----------+ 
| bit 9      | Binary Sensor 9  | 512       | 200       |
+------------+------------------+-----------+-----------+ 
| bit 10     | Binary Sensor 10 | 1024      | 400       |
+------------+------------------+-----------+-----------+ 
| bit 11     | Binary Sensor 11 | 2048      | 800       |
+------------+------------------+-----------+-----------+ 
| bit 12     | Binary Sensor 12 | 4096      | 1000      |
+------------+------------------+-----------+-----------+ 
| bit 13     | Binary Sensor 13 | 8192      | 2000      |
+------------+------------------+-----------+-----------+ 
| bit 14     | Binary Sensor 14 | 16384     | 4000      |
+------------+------------------+-----------+-----------+ 
| bit 15     | Binary Sensor 15 | 32768     | 8000      |
+------------+------------------+-----------+-----------+ 

For example, when reading register ``15``, a decimal value of ``12288`` is the sum of ``4096`` + ``8192``, meaning the corresponding bits ``12`` and ``13`` are ``1``, the other bits are ``0``. 

To gather some of these bits as binary sensors in ESPHome, use ``bitmask``:

.. code-block:: yaml

    binary_sensor:
    - platform: modbus_controller
      modbus_controller_id: ventilation_system
      name: Alarm bit0
      entity_category: diagnostic
      device_class: problem
      register_type: read
      address: 15
      bitmask: 0x1
    - platform: modbus_controller
      modbus_controller_id: ventilation_system
      name: Alarm bit1
      entity_category: diagnostic
      device_class: problem
      register_type: read
      address: 15
      bitmask: 0x2
    - platform: modbus_controller
      modbus_controller_id: ventilation_system
      name: Alarm bit10
      entity_category: diagnostic
      device_class: problem
      register_type: read
      address: 15
      bitmask: 0x400
    - platform: modbus_controller
      modbus_controller_id: ventilation_system
      name: Alarm bit15
      entity_category: diagnostic
      device_class: problem
      register_type: read
      address: 15
      bitmask: 0x8000



Protocol decoding example
-------------------------

.. code-block:: yaml

    sensors:
      - platform: modbus_controller
        modbus_controller_id: epever
        id: array_rated_voltage
        name: "array_rated_voltage"
        address: 0x3000
        unit_of_measurement: "V"
        register_type: read
        value_type: U_WORD
        accuracy_decimals: 1
        skip_updates: 60
        filters:
          - multiply: 0.01

      - platform: modbus_controller
        modbus_controller_id: epever
        id: array_rated_current
        name: "array_rated_current"
        address: 0x3001
        unit_of_measurement: "V"
        register_type: read
        value_type: U_WORD
        accuracy_decimals: 2
        filters:
          - multiply: 0.01

      - platform: modbus_controller
        modbus_controller_id: epever
        id: array_rated_power
        name: "array_rated_power"
        address: 0x3002
        unit_of_measurement: "W"
        register_type: read
        value_type: U_DWORD_R
        accuracy_decimals: 1
        filters:
          - multiply: 0.01

      -platform: modbus_controller
        modbus_controller_id: epever
        id: battery_rated_voltage
        name: "battery_rated_voltage"
        address: 0x3004
        unit_of_measurement: "V"
        register_type: read
        value_type: U_WORD
        accuracy_decimals: 1
        filters:
          - multiply: 0.01

      - platform: modbus_controller
        modbus_controller_id: epever
        id: battery_rated_current
        name: "battery_rated_current"
        address: 0x3005
        unit_of_measurement: "A"
        register_type: read
        value_type: U_WORD
        accuracy_decimals: 1
        filters:
          - multiply: 0.01

      - platform: modbus_controller
        modbus_controller_id: epever
        id: battery_rated_power
        name: "battery_rated_power"
        address: 0x3006
        unit_of_measurement: "W"
        register_type: read
        value_type: U_DWORD_R
        accuracy_decimals: 1
        filters:
          - multiply: 0.01

      - platform: modbus_controller
        modbus_controller_id: epever id: charging_mode
        name: "charging_mode"
        address: 0x3008
        unit_of_measurement: ""
        register_type: read
        value_type: U_WORD
        accuracy_decimals: 0


To minimize the required transactions all registers with the same base address are read in one request.
The response is mapped to the sensor based on ``register_count`` and offset in bytes. For example:

**Request**

+-----------+-----------------------------------------+
| data      | description                             |
+===========+=========================================+
| 0x1  (01) | device address                          |
+-----------+-----------------------------------------+
| 0x4  (04) | function code 4 (Read Input Registers)  |
+-----------+-----------------------------------------+
| 0x30 (48) | start address high byte                 |
+-----------+-----------------------------------------+
| 0x0  (00) | start address low byte                  |
+-----------+-----------------------------------------+
| 0x0  (00) | number of registers to read high byte   |
+-----------+-----------------------------------------+
| 0x9  (09) | number of registers to read low byte    |
+-----------+-----------------------------------------+
| 0x3f (63) | crc                                     |
+-----------+-----------------------------------------+
| 0xc  (12) | crc                                     |
+-----------+-----------------------------------------+



**Response**

+--------+------------+--------------------+--------------------------------------------+
| offset | data       | value (type)       | description                                |
+========+============+====================+============================================+
|   H    | 0x1  (01)  |                    | device address                             |
+--------+------------+--------------------+--------------------------------------------+
|   H    | 0x4  (04)  |                    | function code                              |
+--------+------------+--------------------+--------------------------------------------+
|   H    | 0x12 (18)  |                    | byte count                                 |
+--------+------------+--------------------+--------------------------------------------+
|   0    | 0x27 (39)  | U_WORD             | array_rated_voltage  high byte             |
+--------+------------+--------------------+--------------------------------------------+
|   1    | 0x10 (16)  | 0x2710 (100000)    | array_rated_voltage  low byte              |
+--------+------------+--------------------+--------------------------------------------+
|   2    | 0x7  (7)   | U_WORD             | array_rated_current  high byte             |
+--------+------------+--------------------+--------------------------------------------+
|   3    | 0xd0 (208) | 0x7d0 (2000)       | array_rated_current  low byte              |
+--------+------------+--------------------+--------------------------------------------+
|   4    | 0xcb (203) | U_DWORD_R          | array_rated_power high byte of low word    |
+--------+------------+--------------------+--------------------------------------------+
|   5    | 0x20 (32)  | spans 2 register   | array_rated_power low byte of low word     |
+--------+------------+--------------------+--------------------------------------------+
|   6    | 0x0  (0)   |                    | array_rated_power high byte of high word   |
+--------+------------+--------------------+--------------------------------------------+
|   7    | 0x0  (0)   | 0x0000CB20 (52000) | array_rated_power low byte of high word    |
+--------+------------+--------------------+--------------------------------------------+
|   8    | 0x9  (09)  | U_WORD             | battery_rated_voltage high byte            |
+--------+------------+--------------------+--------------------------------------------+
|   9    | 0x60 (96)  | 0x960 (2400)       | battery_rated_voltage low byte             |
+--------+------------+--------------------+--------------------------------------------+
|   10   | 0x7  (07)  | U_WORD             | battery_rated_current high word            |
+--------+------------+--------------------+--------------------------------------------+
|   11   | 0xd0 (208) | 0x7d0 (2000)       | battery_rated_current high word            |
+--------+------------+--------------------+--------------------------------------------+
|   12   | 0xcb (203) | U_DWORD_R          | battery_rated_power high byte of low word  |
+--------+------------+--------------------+--------------------------------------------+
|   13   | 0x20 (32)  | spans 2 register   | battery_rated_power low byte of low word   |
+--------+------------+--------------------+--------------------------------------------+
|   14   | 0x0  (0)   |                    | battery_rated_power high byte of high word |
+--------+------------+--------------------+--------------------------------------------+
|   15   | 0x0  (0)   | 0x0000CB20 (52000) | battery_rated_power low byte of high word  |
+--------+------------+--------------------+--------------------------------------------+
|   16   | 0x0  (0)   | U_WORD             | charging_mode high byte                    |
+--------+------------+--------------------+--------------------------------------------+
|   17   | 0x2  (02)  | 0x2 (MPPT)         | charging_mode low  byte                    |
+--------+------------+--------------------+--------------------------------------------+
|   C    | 0x2f (47)  |                    | crc                                        |
+--------+------------+--------------------+--------------------------------------------+
|   C    | 0x31 (49)  |                    | crc                                        |
+--------+------------+--------------------+--------------------------------------------+


.. note::

    Write support is only implemented for switches and selects.
    However the C++ code provides the required API to write to a ModBUS device.

    These methods can be called from a lambda.

    Here is an example how to set config values to for an EPEVER Trace AN controller.
    The code synchronizes the localtime of MCU to the epever controller
    The time is set by writing 12 bytes to register 0x9013.
    Then battery charge settings are sent.
    
    .. code-block:: yaml

        esphome:
          on_boot:
            ## configure controller settings at setup
            ## make sure priority is lower than setup_priority of modbus_controller
            priority: -100
            then:
              - lambda: |-
                  // get local time and sync to controller
                  time_t now = ::time(nullptr);
                  struct tm *time_info = ::localtime(&now);
                  int seconds = time_info->tm_sec;
                  int minutes = time_info->tm_min;
                  int hour = time_info->tm_hour;
                  int day = time_info->tm_mday;
                  int month = time_info->tm_mon + 1;
                  int year = time_info->tm_year % 100;
                  esphome::modbus_controller::ModbusController *controller = id(epever);
                  // if there is no internet connection localtime returns year 70
                  if (year != 70) {
                    // create the payload
                    std::vector<uint16_t> rtc_data = {uint16_t((minutes << 8) | seconds), uint16_t((day << 8) | hour),
                                                      uint16_t((year << 8) | month)};
                    // Create a ModBUS command item with the time information as the payload
                    esphome::modbus_controller::ModbusCommandItem set_rtc_command =
                        esphome::modbus_controller::ModbusCommandItem::create_write_multiple_command(controller, 0x9013, 3, rtc_data);
                    // Submit the command to the send queue
                    epever->queue_command(set_rtc_command);
                    ESP_LOGI("ModbusLambda", "EPSOLAR RTC set to %02d:%02d:%02d %02d.%02d.%04d", hour, minutes, seconds, day, month,
                            year + 2000);
                  }
                  // Battery settings
                  // Note: these values are examples only and apply my AGM Battery
                  std::vector<uint16_t> battery_settings1 = {
                      0,       // 9000 Battery Type 0 =  User
                      0x0073,  // 9001 Battery Cap 0x55 == 115AH
                      0x012C,  // 9002 Temp compensation -3V /°C/2V
                      0x05DC,  // 9003 0x5DC == 1500 Over Voltage Disconnect Voltage 15,0
                      0x058C,  // 9004 0x58C == 1480 Charging Limit Voltage 14,8
                      0x058C,  // 9005 Over Voltage Reconnect Voltage 14,8
                      0x05BF,  // 9006 Equalize Charging Voltage 14,6
                      0x05BE,  // 9007 Boost Charging Voltage 14,7
                      0x0550,  // 9008 Float Charging Voltage 13,6
                      0x0528,   // 9009 Boost Reconnect Charging Voltage 13,2
                      0x04C4,  // 900A Low Voltage Reconnect Voltage 12,2
                      0x04B0,  // 900B Under Voltage Warning Reconnect Voltage 12,0
                      0x04BA,  // 900c Under Volt. Warning Volt 12,1
                      0x04BA,  // 900d Low Volt. Disconnect Volt. 11.8
                      0x04BA   // 900E Discharging Limit Voltage 11.8
                  };
    
                  // Boost and equalization periods
                  std::vector<uint16_t> battery_settings2 = {
                      0x0000,  // 906B Equalize Duration (min.) 0
                      0x0075   // 906C Boost Duration (aka absorb) 117 mins
                  };
                  esphome::modbus_controller::ModbusCommandItem set_battery1_command =
                      esphome::modbus_controller::ModbusCommandItem::create_write_multiple_command(controller, 0x9000, battery_settings1.size() ,
                                                                                                  battery_settings1);
    
                  esphome::modbus_controller::ModbusCommandItem set_battery2_command =
                      esphome::modbus_controller::ModbusCommandItem::create_write_multiple_command(controller, 0x906B, battery_settings3.size(),
                                                                                                  battery_settings2);
                  delay(200) ;
                  controller->queue_command(set_battery1_command);
                  delay(200) ;
                  controller->queue_command(set_battery2_command);
                  ESP_LOGI("ModbusLambda", "EPSOLAR Battery set");
    
        uart:
          id: mod_bus
          tx_pin: 19
          rx_pin: 18
          baud_rate: 115200
          stop_bits: 1
    
        modbus:
          #flow_control_pin: 23
          send_wait_time: 200ms
          id: mod_bus_epever
    
        modbus_controller:
          - id: epever
            ## the Modbus device addr
            address: 0x1
            modbus_id: mod_bus_epever
            command_throttle: 0ms
            setup_priority: -10
            update_interval: ${updates}
    
        sensor:
          - platform: modbus_controller
            modbus_controller_id: epever
            id: array_rated_voltage
            name: "array_rated_voltage"
            address: 0x3000
            unit_of_measurement: "V"
            register_type: read
            value_type: U_WORD
            accuracy_decimals: 1
            filters:
              - multiply: 0.01
    
          - platform: modbus_controller
            modbus_controller_id: epever
            id: array_rated_current
            name: "array_rated_current"
            address: 0x3001
            unit_of_measurement: "A"
            register_type: read
            value_type: U_WORD
            accuracy_decimals: 2
            filters:
              - multiply: 0.01
    
          - platform: modbus_controller
            modbus_controller_id: epever
            id: array_rated_power
            name: "array_rated_power"
            address: 0x3002
            unit_of_measurement: "W"
            register_type: read
            value_type: U_DWORD_R
            accuracy_decimals: 1
            filters:
              - multiply: 0.01


See Also
--------

- :doc:`/components/modbus`
- :doc:`/components/binary_sensor/modbus_controller`
- :doc:`/components/text_sensor/modbus_controller`
- :doc:`/components/switch/modbus_controller`
- :doc:`/components/number/modbus_controller`
- :doc:`/components/output/modbus_controller`
- `ModBUS RTU Protocol Description <https://www.modbustools.com/modbus.html>`__
- `EPEVER MPPT Solar Charge Controller (Tracer-AN Series) <https://devices.esphome.io/devices/epever_mptt_tracer_an>`__
- `Genvex, Nibe, Alpha-Innotec heat recovery ventilation <https://devices.esphome.io/devices/Genvex-Nibe-AlphaInnotec-heat-recovery-ventilation>`__
- :ghedit:`Edit`
