- coil: coils are also called discrete output. Coils are 1-bit registers (on/off values) that are used to control discrete outputs. Read and Write access. 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. Read and Write access. 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
-**value_type**: (**Required**): datatype of the mod_bus register data. The default data type for modbus is a 16 bit integer in big endian format (MSB first)
-**bitmask**: (*Optional*) some values are packed in a response. The bitmask can be used to extract a value from the response. For example, if the high byte value register 0x9013 contains the minute value of the current time. To only exctract this value use bitmask: 0xFF00. The result will be automatically right shifted by the number of 0 before the first 1 in the bitmask. For 0xFF00 (0b1111111100000000) the result is shifted 8 posistions. More than one sensor can use the same address/offset if the bitmask is different.
-**skip_updates**: (*Optional*, int): By default all sensors of 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 component by address ranges to reduce number of transactions. All compoents with the same address will be updated in one request. skip_updates applies for all components in the same range.
The default size for 1 register is 16 bits (1 Word). Some devices are not adhering to this convention and have registers larger than 16 bits. In this case ``register_count`` and ``response_size`` must be set. For example, if your modbus device uses 1 registers for a FP32 value instead the default of two set ``register_count: 1`` and ``response_size: 4``.
-**response_size**: (*Optional*): 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.
-**custom_data** (*Optional*, list of bytes): raw bytes for modbus command. This allows using non-standard commands. If ``custom_data`` 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_data` how to use ``custom_command``
Lambda to be evaluated every update interval to get the new value of the sensor.
-**offset**: (*Optional*, int): only required for uncommon response encodings
offset from start address in bytes. If more than one register is read a modbus read registers 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.
- All other options from :ref:`Sensor <config-sensor>`.
This example will send 2 modbus commands (device address 1 assumed)
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.
``register_count`` can also be used to skip a register in consecutive range.
An example is a SDM meter:
..code-block:: yaml
- platform: modbus_controller
name: "Voltage Phase 1"
address: 0
register_type: "read"
value_type: FP32
- platform: modbus_controller
name: "Voltage Phase 2"
address: 2
register_type: "read"
value_type: FP32
- platform: modbus_controller
name: "Voltage Phase 3"
address: 4
register_type: "read"
value_type: FP32
- platform: modbus_controller
name: "Current Phase 1"
address: 6
register_type: "read"
value_type: FP32
accuracy_decimals: 1
Maybe you don’t care about the Voltage value for Phase 2 and Phase 3 (or you have a SDM-120).
Of course, you can delete the sensors your don’t care about. But then you have a gap in the addresses. The configuration above will generate one modbus command `read multiple registers from 0 to 6`. If you remove the registers at address 2 and 4 then 2 commands will be generated `read register 0` and `read register 6`.
To avoid the generation of multiple commands and reduce the amount of uart communication ``register_count`` can be used to fill the gaps
..code-block:: yaml
- platform: modbus_controller
name: "Voltage Phase 1"
address: 0
unit_of_measurement: "V"
register_type: "read"
value_type: FP32
register_count: 6
- platform: modbus_controller
name: "Current Phase 1"
address: 6
register_type: "read"
value_type: FP32
Because `register_count: 6` is used for the first register the command “read registers from 0 to 6” can still be used but the values in between are ignored.
**Calculation:** FP32 is a 32 bit value and uses 2 registers. Therefore, to skip the 2 FP32 registers the size of these 2 registers must be added to the default size for the first register.
So we have 2 for address 0, 2 for address 2 and 2 for address 4 then ``register_count`` must be 6.
