档案馆环境异常联动策略：温湿度超标自动启动恒湿净化一体机策略

传感器多点采集
  → 滑动均值/趋势判断
    → 持续超标延时判定
      → 分级策略（预警/微调/强制）
        → 加湿除湿互锁
          → 错峰下发 Modbus 指令
            → 回读状态字确认
              → 平台记审计日志

# humidity_decision.py
from collections import deque

class HumidityLinkage:
    def __init__(self, window=12, sustain_sec=30,
                 hi_start=63.0, hi_stop=58.0,
                 lo_start=42.0, lo_stop=47.0):
        self.buf = deque(maxlen=window)
        self.sustain_sec = sustain_sec
        self.hi_start, self.hi_stop = hi_start, hi_stop
        self.lo_start, self.lo_stop = lo_start, lo_stop
        self.state = "idle"   # idle / dehumid / humidify

    def feed(self, rh: float, dt_sec: int = 5) -> dict:
        self.buf.append(rh)
        if len(self.buf) < self.buf.maxlen:
            return {"action": "none", "reason": "warmup"}

        avg = sum(self.buf) / len(self.buf)
        over_cnt = sum(1 for x in self.buf if x > self.hi_start)
        under_cnt = sum(1 for x in self.buf if x < self.lo_start)
        sustained_over = over_cnt * dt_sec >= self.sustain_sec
        sustained_under = under_cnt * dt_sec >= self.sustain_sec

        # 状态机：先停再切，互锁
        if self.state == "idle":
            if sustained_over:
                self.state = "dehumid"
                return {"action": "start_dehumid", "avg": avg}
            if sustained_under:
                self.state = "humidify"
                return {"action": "start_humidify", "avg": avg}
            return {"action": "none", "avg": avg}

        if self.state == "dehumid":
            if avg <= self.hi_stop:
                self.state = "idle"
                return {"action": "stop_dehumid", "avg": avg}
            return {"action": "keep_dehumid", "avg": avg}

        if self.state == "humidify":
            if avg >= self.lo_stop:
                self.state = "idle"
                return {"action": "stop_humidify", "avg": avg}
            return {"action": "keep_humidify", "avg": avg}

1. 读 40016 local_remote_mode → 必须=1（远程）
2. 读 40015 safety_interlock → 有人/门开/消防 则只许恒湿，禁消毒
3. 写 40001 run_mode = 1（自动）或 3（除湿）/2（加湿）
4. 写 40002 target_rh = 550 （55.0%RH）
5. 写 40004 湿控死区 = 50 （5.0%RH）
6. 写 40009 purify_enable = 1
7. 回读 40001 / 40009 / 40018 确认
8. 写审计：who / when / before / after / slave_id / func / raw / result