88 lines
3.0 KiB
Python
88 lines
3.0 KiB
Python
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"""Modbus TCP protocol collector."""
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import struct
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from typing import Optional
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from pymodbus.client import AsyncModbusTcpClient
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from app.collectors.base import BaseCollector
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class ModbusTcpCollector(BaseCollector):
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"""Collect data from devices via Modbus TCP.
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connection_params example:
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{
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"host": "192.168.1.100",
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"port": 502,
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"slave_id": 1,
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"registers": [
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{"address": 0, "count": 2, "data_type": "active_power", "scale": 0.1, "unit": "kW"},
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{"address": 2, "count": 2, "data_type": "voltage", "scale": 0.1, "unit": "V"}
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]
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}
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"""
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def __init__(self, device_id, device_code, connection_params, collect_interval=15):
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super().__init__(device_id, device_code, connection_params, collect_interval)
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self._client: Optional[AsyncModbusTcpClient] = None
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self._host = connection_params.get("host", "127.0.0.1")
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self._port = connection_params.get("port", 502)
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self._slave_id = connection_params.get("slave_id", 1)
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self._registers = connection_params.get("registers", [])
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async def connect(self):
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self._client = AsyncModbusTcpClient(
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self._host,
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port=self._port,
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timeout=5,
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)
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connected = await self._client.connect()
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if not connected:
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raise ConnectionError(f"Cannot connect to Modbus TCP {self._host}:{self._port}")
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async def disconnect(self):
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if self._client:
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self._client.close()
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self._client = None
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async def collect(self) -> dict:
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if not self._client or not self._client.connected:
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raise ConnectionError("Modbus client not connected")
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data = {}
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for reg in self._registers:
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address = reg["address"]
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count = reg.get("count", 1)
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data_type = reg["data_type"]
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scale = reg.get("scale", 1.0)
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unit = reg.get("unit", "")
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result = await self._client.read_holding_registers(
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address, count=count, slave=self._slave_id
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)
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if result.isError():
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self.logger.warning(
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"Modbus read error at address %d for %s: %s",
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address, self.device_code, result,
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)
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continue
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raw_value = self._decode_registers(result.registers, count)
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value = round(raw_value * scale, 4)
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data[data_type] = (value, unit)
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return data
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@staticmethod
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def _decode_registers(registers: list, count: int) -> float:
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"""Decode register values to a numeric value."""
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if count == 1:
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return float(registers[0])
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elif count == 2:
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# Two 16-bit registers -> 32-bit float (big-endian)
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raw = struct.pack(">HH", registers[0], registers[1])
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return struct.unpack(">f", raw)[0]
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else:
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# Fallback: treat as concatenated 16-bit values
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return float(registers[0])
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