TwinCAT OPC UA：通过直接访问单独设置发布速率

我已经配置了TwinCAT OPC UA服务器，需要对约400字节的关键变量实现1000Hz的高速循环数据交换。但如果在XML配置中为所有变量设置1ms发布速率，会导致CPU占用100%且通信失效。请问能否通过变量属性（如下方示例代码）为不同变量单独设置发布速率？

示例代码（ST变量定义） #

{attribute 'OPC.UA.DA' := '1'}
//{datarate := 1000Hz}
CriticalData : Struct_of_CriticalData;
//{datarate := 10Hz} 
UncriticalData : Struct_of_UncriticalData;
{attribute 'OPC.UA.DA' := '0'}

当前OPC UA服务器XML配置 #

<?xml version="1.0"?>
<OpcServerConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <UaServerConfig>
    <MaxRequestAge>0</MaxRequestAge>
    <MaxSessionCount>100</MaxSessionCount>
    <MinSessionTimeout>10000</MinSessionTimeout>
    <MaxSessionTimeout>3600000</MaxSessionTimeout>
    <MaxBrowseContinuationPoints>0</MaxBrowseContinuationPoints>
    <MaxHistoryContinuationPoints>0</MaxHistoryContinuationPoints>
    <MinPublishingInterval>1</MinPublishingInterval>
    <MaxPublishingInterval>0</MaxPublishingInterval>
    <MinKeepAliveInterval>5000</MinKeepAliveInterval>
    <MinSubscriptionLifetime>10000</MinSubscriptionLifetime>
    <MaxSubscriptionLifetime>0</MaxSubscriptionLifetime>
    <MaxRetransmitionQueueSize>10</MaxRetransmitionQueueSize>
    <MaxNotificationsPerPublish>0</MaxNotificationsPerPublish>
    <MaxDataQueueSize>100</MaxDataQueueSize>
    <MaxEventQueueSize>10000</MaxEventQueueSize>
    <MaxSubscriptionCount>0</MaxSubscriptionCount>
    <MaxMonitoredItemCount>0</MaxMonitoredItemCount>
    <MaxMonitoredItemPerSubscriptionCount>0</MaxMonitoredItemPerSubscriptionCount>
    <AvailableLocaleIds>
      <LocaleId>en</LocaleId>
    </AvailableLocaleIds>
    <AvailableServerProfiles>
      <ServerProfileUri>http://opcfoundation.org/UAProfile/Server/StandardUA</ServerProfileUri>
      <ServerProfileUri>http://opcfoundation.org/UAProfile/Server/DataAccess</ServerProfileUri>
      <ServerProfileUri>http://opcfoundation.org/UAProfile/Server/Methods</ServerProfileUri>
      <ServerProfileUri>http://opcfoundation.org/UAProfile/Server/EventSubscription</ServerProfileUri>
    </AvailableServerProfiles>
    <IsAuditActivated>false</IsAuditActivated>
    <RedundancySettings>
      <RedundancySupport>None</RedundancySupport>
    </RedundancySettings>
    <MinSupportedSampleRate>0</MinSupportedSampleRate>
    <AvailableSamplingRates>
      <SamplingRate>1</SamplingRate>
      <SamplingRate>2</SamplingRate>
      <SamplingRate>3</SamplingRate>
      <SamplingRate>4</SamplingRate>
      <SamplingRate>5</SamplingRate>
      <SamplingRate>6</SamplingRate>
      <SamplingRate>7</SamplingRate>
      <SamplingRate>8</SamplingRate>
      <SamplingRate>9</SamplingRate>
      <SamplingRate>10</SamplingRate>
      <SamplingRate>15</SamplingRate>
      <SamplingRate>20</SamplingRate>
      <SamplingRate>25</SamplingRate>
      <SamplingRate>30</SamplingRate>
      <SamplingRate>35</SamplingRate>
      <SamplingRate>40</SamplingRate>
      <SamplingRate>45</SamplingRate>
      <SamplingRate>50</SamplingRate>
      <SamplingRate>60</SamplingRate>
      <SamplingRate>70</SamplingRate>
      <SamplingRate>80</SamplingRate>
      <SamplingRate>90</SamplingRate>
      <SamplingRate>100</SamplingRate>
      <SamplingRate>150</SamplingRate>
      <SamplingRate>200</SamplingRate>
      <SamplingRate>250</SamplingRate>
      <SamplingRate>300</SamplingRate>
      <SamplingRate>350</SamplingRate>
      <SamplingRate>400</SamplingRate>
      <SamplingRate>450</SamplingRate>
      <SamplingRate>500</SamplingRate>
      <SamplingRate>550</SamplingRate>
      <SamplingRate>600</SamplingRate>
      <SamplingRate>650</SamplingRate>
      <SamplingRate>700</SamplingRate>
      <SamplingRate>750</SamplingRate>
      <SamplingRate>800</SamplingRate>
      <SamplingRate>850</SamplingRate>
      <SamplingRate>900</SamplingRate>
      <SamplingRate>950</SamplingRate>
      <SamplingRate>1000</SamplingRate>
      <SamplingRate>2000</SamplingRate>
      <SamplingRate>5000</SamplingRate>
      <SamplingRate>10000</SamplingRate>
    </AvailableSamplingRates>
</OpcServerConfig>

解决方案 #

可以通过TwinCAT变量属性配置结合OPC UA订阅分组实现差异化数据更新，具体操作如下：

• 为变量配置采样速率属性
  TwinCAT支持使用{attribute 'OPC.UA.SamplingInterval' := 'X'}（X为毫秒数）为单个变量指定采样间隔，替代你示例中注释的自定义格式。注意取值必须在XML配置的AvailableSamplingRates列表内，你的配置已包含1和100，符合需求。修正后的ST代码：

  {attribute 'OPC.UA.DA' := '1'}
  {attribute 'OPC.UA.SamplingInterval' := '1'} // 1ms采样，对应1000Hz
  CriticalData : Struct_of_CriticalData;
  
  {attribute 'OPC.UA.SamplingInterval' := '100'} // 100ms采样，对应10Hz
  UncriticalData : Struct_of_UncriticalData;
  {attribute 'OPC.UA.DA' := '0'}
  

• 客户端创建对应发布间隔的订阅
  服务器端的采样速率配置需要配合客户端的订阅设置才能生效：

  • 为CriticalData创建发布间隔为1ms的订阅
  • 为UncriticalData创建发布间隔为100ms的订阅
    这样服务器会根据订阅的发布间隔分配资源，避免全变量高速更新导致的CPU过载。

• XML配置优化（可选）
  现有配置的MinPublishingInterval已设为1ms，满足高速需求，但可调整MaxDataQueueSize至200，提升高速数据的缓存能力，避免数据溢出：

  <MaxDataQueueSize>200</MaxDataQueueSize>
  

补充说明 #

• TwinCAT OPC UA服务器不会自动为变量分配不同发布速率，必须结合客户端订阅配置实现差异化更新
• 400字节关键变量在1000Hz下的带宽需求约为3.2Mbps，需确保网络带宽充足，避免通信瓶颈

内容的提问来源于stack exchange，提问作者Paul