-``coil``: Coils are 1-bit registers (ON/OFF values) that are used to control discrete outputs. They may be read and/or written. Modbus *Function Code 1 (Read Coil Status)* will be used.
-``discrete_input``: discrete input register (read only coil) are similar to coils but can only be read. Modbus *Function Code 2 (Read Input Status)* will be used.
-``holding``: Holding Registers - Holding registers are the most universal 16-bit register. They may be read and/or written. Modbus *Function Code 3 (Read Holding Registers)* will be used.
-``read``: Read Input Registers - registers are 16-bit registers used for input, and may only be read. Modbus *Function Code 4 (Read Input Registers)* will be used.
-**address** (**Required**, int): start address of the first register in a range (can be decimal or hexadecimal).
-**value_type** (**Required**): data type of the modbus register data. The default data type for modbus is a 16 bit integer in big endian format (MSB first).
-**bitmask** (*Optional*, int): sometimes multiple values are packed in a single register's response. The bitmask can be used to extract a value from the response. See :ref:`bitmasks`.
-**skip_updates** (*Optional*, int): By default, all sensors of a modbus_controller are updated together. For data points that don't change very frequently, updates can be skipped. A value of 5 would only update this sensor range in every 5th update cycle. Note: The modbus_controller groups components by address ranges to reduce number of transactions. All components with the same starting address will be updated in one request. ``skip_updates`` applies for *all* components in the same range.
-**register_count** (*Optional*, int): The number of consecutive registers this read request should span or skip in a single command. Default is 1. See :ref:`modbus_register_count` for more details.
-**response_size** (*Optional*, int): Size of the response for the register in bytes. Defaults to register_count*2.
-**force_new_range** (*Optional*, boolean): If possible sensors with sequential addresses are grouped together and requested in one range. Setting ``force_new_range: true`` enforces the start of a new range at that address.
-**x** (float): The parsed float value of the modbus data
-**data** (std::vector<uint8_t): vector containing the complete raw modbus response bytes for this sensor
*note:* because the response contains data for all registers in the same range you have to use ``data[item->offset]`` to get the first response byte for your sensor.
-**item** (const pointer to a SensorItem derived object): The sensor object itself.
Possible return values for the lambda:
-``return <FLOATING_POINT_NUMBER>;`` the new value for the sensor.
-``return NAN;`` if the state should be considered invalid to indicate an error (advanced).
-**custom_command** (*Optional*, list of bytes): raw bytes for modbus command. This allows using non-standard commands. If ``custom_command`` is used ``address`` and ``register_type`` can't be used.
Custom data must contain all required bytes including the modbus device address. The CRC is automatically calculated and appended to the command.
See :ref:`modbus_custom_command` how to use ``custom_command``
-**offset** (*Optional*, int): Offset from start address in bytes (only required for uncommon response encodings). If more than one register is written in a command this value is used to find the start of this datapoint relative to start address. The component calculates the size of the range based on offset and size of the value type. For ``coil`` or ``discrete_input`` registers offset is the position of the coil/register because these registers encode 8 coils in one byte.
