Modbus Controller Number

The modbus_controller platform creates a Number from a modbus_controller. When the Number is updated a modbus write command is created sent to the device.

Configuration variables

register_type (Optional): the type of register to write. One of holding (default), coil, or custom.
address (Required, int): start address of the first register in a range (can be decimal or hexadecimal).
value_type (Optional): datatype of the modbus register data. Defaults to U_WORD, a 16 bit integer in big endian format (MSB first):
- U_WORD (unsigned 16 bit integer from 1 register = 16bit)
- S_WORD (signed 16 bit integer from 1 register = 16bit)
- U_WORD_S (unsigned 16 bit integer from 1 register with bytes swapped within the register = 16bit)
- S_WORD_S (signed 16 bit integer from 1 register with bytes swapped within the register = 16bit)
- U_DWORD (unsigned 32 bit integer from 2 registers = 32bit)
- S_DWORD (signed 32 bit integer from 2 registers = 32bit)
- U_DWORD_R (unsigned 32 bit integer from 2 registers low word first)
- S_DWORD_R (signed 32 bit integer from 2 registers low word first)
- U_QWORD (unsigned 64 bit integer from 4 registers = 64bit)
- S_QWORD (signed 64 bit integer from 4 registers = 64bit)
- U_QWORD_R (unsigned 64 bit integer from 4 registers low word first)
- S_QWORD_R (signed 64 bit integer from 4 registers low word first)
- FP32 (32 bit IEEE 754 floating point from 2 registers)
- FP32_R (32 bit IEEE 754 floating point - same as FP32 but low word first)

WARNING

U_WORD_S and S_WORD_S are a rare, non-standard configuration: the two bytes within one 16-bit register are reversed (LSB first on the wire within that register). Modbus registers are big-endian (MSB first) per the specification. The _S suffix is not the same as _R (word order reversed / low word first across multiple registers).

min_value (Optional, float): The minimum value this number can be.
max_value (Optional, float): The maximum value this number can be.
step (Optional, float): The granularity with which the number can be set. Defaults to 1.
multiply (Optional, float): multiply the new value with this factor before sending the requests. Ignored if lambda is defined.
use_write_multiple (Optional, boolean): By default the modbus command Function Code 6 (Preset Single Registers) is used for setting the holding register if only one register is set. If your device only supports Function Code 16 (Preset Multiple Registers) set this option to true.
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 6th 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.
response_size (Optional): Size of the response for the register in bytes. If unset, defaults to the size implied by value_type (2 bytes per register).
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.
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.
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 Using custom_command how to use custom_command
lambda (Optional, lambda): Lambda to be evaluated every update interval to get the new value of the number.

Parameters passed into the lambda
- x (float): The parsed float value of the modbus data
- data (std::span<const uint8_t>): span containing the complete raw modbus response bytes for this number 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 number.
- item (pointer to a SensorItem derived object): The number object itself.
Possible return values for the lambda:
- return <FLOATING_POINT_NUMBER>; the new value for the number.
- return NAN; if the state should be considered invalid to indicate an error (advanced).
write_lambda (Optional, lambda): Lambda called before send. Lambda is evaluated before the modbus write command is created.

Parameters passed into the lambda
- x (float): The float value to be sent to the modbus device
- payload (std::vector<uint16_t> &payload): empty vector for the payload. The lambda can add 16 bit raw modbus register words.
- item (pointer to a SensorItem derived object): The number object itself.
Possible return values for the lambda:
- return <FLOATING_POINT_NUMBER>; the new value for the number.
- return <anything>; and fill payload with data if the payload is added from the lambda then these 16 bit words will be sent
- return {}; if you don’t want write the command to the device (or do it from the lambda).
All other options from Number.

Example

number:
  - platform: modbus_controller
    modbus_controller_id: modbus1
    id: battery_capacity_number
    name: "Battery Cap Number"
    address: 0x9001
    value_type: U_WORD
    multiply: 1.0

  - platform: modbus_controller
    modbus_controller_id: modbus1
    id: battery_capacity_number
    name: "Battery Cap Number"
    address: 0x9001
    value_type: U_WORD
    lambda: "return  x * 1.0; "
    write_lambda: |-
      ESP_LOGD("main","Modbus Number incoming value = %f",x);
      uint16_t b_capacity = x ;
      payload.push_back(b_capacity);
      return x * 1.0 ;

Modbus Controller Number

Configuration variables

Example

See Also