综合场景例程 4：新风机组（时段启停 + 送风 PI + 防冻 + 滤网堵塞）

这一页只讲这一个例程。母页 b-05-integrated-scenarios 里留着例程 1，其余例程各自一页、在那一页的目录里点。

场景：组合式空调机组的标准配置：按时间段自动启停、按送风温度调水阀、盘管防冻优先、滤网压差报警。

软元件

软元件	作用
M610	时段条件
M611	风机故障
X30	急停
M600	机组运行
D110	送风温度
D112	盘管温度（防冻探头）
D640	滤网压差
D230	水阀开度
Y0	送风机
Y20	滤网堵塞报警

块图（照着拖即可）

对应的 ddc.json（点「生成 JSON」得到的就是它；也可存成 .ddc.json 导入）

{
  "version": 1,
  "name": "新风机组",
  "scan_ms": 500,
  "lines": [
    {
      "op": "assign",
      "target": {"op":"ref","device":"M","addr":600},
      "expr": {
        "op": "rs",
        "id": "rs_ahu",
        "args": [
          {"op":"ref","device":"M","addr":610},
          {
            "op": "or",
            "args": [{"op":"ref","device":"M","addr":611},{"op":"ref","device":"X","addr":30}]
          }
        ]
      }
    },
    {
      "op": "assign",
      "target": {"op":"ref","device":"D","addr":210},
      "expr": {
        "op": "pi",
        "id": "pi_ahu",
        "args": [
          {"op":"ref","device":"M","addr":600},
          {"op":"const","value":1},
          {"op":"ref","device":"D","addr":110},
          {"op":"const","value":18},
          {"op":"const","value":1},
          {"op":"const","value":10},
          {"op":"const","value":128}
        ]
      }
    },
    {
      "op": "assign",
      "target": {"op":"ref","device":"M","addr":601},
      "expr": {
        "op": "cmp",
        "cmp": "<=",
        "args": [{"op":"ref","device":"D","addr":112},{"op":"const","value":5}]
      }
    },
    {
      "op": "if",
      "cond": {
        "op": "or",
        "args": [
          {"op":"ref","device":"M","addr":601},
          {"op":"not","args":[{"op":"ref","device":"M","addr":600}]}
        ]
      },
      "then": [
        {
          "op": "assign",
          "target": {"op":"ref","device":"D","addr":230},
          "expr": {"op":"const","value":100}
        }
      ],
      "else": [
        {
          "op": "assign",
          "target": {"op":"ref","device":"D","addr":230},
          "expr": {
            "op": "limit",
            "args": [
              {"op":"ref","device":"D","addr":210},
              {"op":"const","value":10},
              {"op":"const","value":90}
            ]
          }
        }
      ]
    },
    {
      "op": "assign",
      "target": {"op":"ref","device":"Y","addr":0},
      "expr": {
        "op": "and",
        "args": [
          {"op":"ref","device":"M","addr":600},
          {"op":"not","args":[{"op":"ref","device":"M","addr":601}]}
        ]
      }
    },
    {
      "op": "assign",
      "target": {"op":"ref","device":"Y","addr":20},
      "expr": {
        "op": "cmp",
        "cmp": ">=",
        "args": [{"op":"ref","device":"D","addr":640},{"op":"const","value":200}]
      }
    }
  ]
}

要点

• 防冻优先于温度调节：用「如果」整段覆盖输出（水阀全开 + 停风机），而不是在 PI 里加条件——防冻是安全动作，不能被调节逻辑覆盖。
• 防冻的两个动作缺一不可：停风机 + 全开水阀。只做一个，盘管照样冻裂。
• 滤网压差是报警不是控制：提醒清洗即可，不要用它去停机组（会频繁误停）。

验证：M610 = 1 → M600 = 1、Y0 = 1；把 D112 写成 3 → D230 = 100、Y0 = 0、M601 = 1；D640 写 250 → Y20 = 1。

注意事项

• 只靠 PI 的使能做防冻：使能只停止调节，输出停在原值，阀可能是关的——冻裂风险就在这里。
• 冬夏共用一套参数：冬季要换成加热（正比例 = 0）并改设定值和防冻阈值。
• 时段条件或故障没并进停止孔：下班后机组还在跑，或故障时不停机。