modbus-server-nd/modbus_codec.py

"""Encode point values to Modbus registers."""

import struct


def encode_registers(value: object, data_type: str) -> list[int]:
    if value is None:
        value = 0

    if data_type == "int16":
        packed = struct.pack(">h", int(value))
    elif data_type == "int32":
        packed = struct.pack(">i", int(value))
    elif data_type == "float32":
        packed = struct.pack(">f", float(value))
    else:
        raise ValueError(f"unsupported data_type: {data_type}")

    return [int.from_bytes(packed[index:index + 2], "big") for index in range(0, len(packed), 2)]