Triggering Links

概述

OPC UA Part 4 §5.12.5 SetTriggering 把一个 MI 设为 trigger, 触发时把一组 linked MI 一并 burst 上报。典型场景: 阈值触发时回吐窗口数据 (类 PLC 故障录波)。

API

方法	类别	读写	说明
sub.add_triggering_links(trigger_mi, linked_mis)	写	写	添加联动, 返回每条 link 的 StatusCode
sub.remove_triggering_links(trigger_mi, linked_mis)	写	写	移除

代码示例

from opcua import (
    DarraOpcUa, AttributeId, MonitoringMode, StatusCode
)

with DarraOpcUa("opc.tcp://localhost:4840") as ua:
    ua.connect()
    sub = ua.create_subscription(100)

    # 1) 阈值监控 (trigger), Reporting
    trig_mi = sub.add("ns=2;s=Temp.High", AttributeId.VALUE, 200)

    # 2) 高频信号 (linked), Sampling — 平时不上报
    mi1 = sub.add("ns=2;s=Vibration.X", AttributeId.VALUE, 50,
                  MonitoringMode.SAMPLING, 10, True, None)
    mi2 = sub.add("ns=2;s=Vibration.Y", AttributeId.VALUE, 50,
                  MonitoringMode.SAMPLING, 10, True, None)
    mi3 = sub.add("ns=2;s=Vibration.Z", AttributeId.VALUE, 50,
                  MonitoringMode.SAMPLING, 10, True, None)

    # 3) 设置联动
    add_res = sub.add_triggering_links(trig_mi, [mi1, mi2, mi3])
    for i, rc in enumerate(add_res):
        print(f"link[{i}] = {rc}")

    @sub.on_data_changed
    def on_dc(args):
        print(f"[mi={args.client_handle}] {args.value.value}")

    # 4) 解除联动
    sub.remove_triggering_links(trig_mi, [mi3])

实现说明

• Stack 不提供 set_triggering PInvoke 时返回每项 BAD_NOT_SUPPORTED, 推 Diagnostic Warn 事件
• 服务端不支持时返回 BAD_SERVICE_UNSUPPORTED, 极少见

与 MonitoringMode 配合

trigger Mode	linked Mode	行为
REPORTING	SAMPLING	trigger fire 时 linked burst 上报 (典型)
REPORTING	DISABLED	linked 完全不上报
SAMPLING	SAMPLING	都不上报, 无效

最佳实践

• 录波场景: trigger 阈值 + Reporting, linked 高频 + Sampling
• trigger 数 ≤ 10
• trigger 和 linked 必须在同一个 Subscription
• 退出窗口前主动 remove

跨语言对照

C#	Python	Java	C++	Rust	C
AddTriggeringLinks	add_triggering_links	addTriggeringLinks	AddTriggeringLinks	add_triggering_links	DarraUa_Subscription_AddTriggeringLinks

下一步

• Set Monitoring Mode
• Subscription 自恢复