OpcUA Open62541 PubSub：如何发布值更改？

问题描述 投票：0回答：1

这是我在https://github.com/open62541/open62541/issues/3275

你好，

我试图了解PubSub的工作方式。我的理解是，发布者将更改发布到OPC UA中间件，订阅发布者的订户将收到OPC UA中间件的通知。我看一下这个例子：https://github.com/open62541/open62541/blob/v1.0/examples/pubsub/tutorial_pubsub_publish.c我们可以看到，在发布者方面，我们需要：

addPubSubConnection(server, transportProfile, networkAddressUrl);  
addPublishedDataSet(server);  
addDataSetField(server);  
addWriterGroup(server);  
addDataSetWriter(server);

发布的数据是在addDataSetField内部创建的，在这种情况下是服务器时间，然后服务器时间将在多播网络上连续发布。就我而言，我只想更新单个变量，当满足某些条件时说uint32变量。为此，我如下更改addDataSetField，然后在另一个线程中调用Update（）以更新变量。

UA_NodeId published_dataSet_id_, dataSet_field_id_;

static void
addDataSetField(UA_Server *server) {
    /* Add a field to the previous created PublishedDataSet */
    //UA_NodeId dataSetFieldIdent;
    UA_DataSetFieldConfig dataSetFieldConfig;
    memset(&dataSetFieldConfig, 0, sizeof(UA_DataSetFieldConfig));
    dataSetFieldConfig.dataSetFieldType = UA_PUBSUB_DATASETFIELD_VARIABLE;
    dataSetFieldConfig.field.variable.fieldNameAlias = UA_STRING("Server localtime");
    dataSetFieldConfig.field.variable.promotedField = UA_FALSE;
    dataSetFieldConfig.field.variable.publishParameters.publishedVariable =
    //UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_SERVERSTATUS_CURRENTTIME);
    UA_NODEID_NUMERIC(0, UA_NS0ID_UINT32);

    dataSetFieldConfig.field.variable.publishParameters.attributeId = UA_ATTRIBUTEID_VALUE;
    UA_Server_addDataSetField(server, published_dataSet_id_,
                              &dataSetFieldConfig, &dataSet_field_id_);
}

void Update()
{
        UA_Int32 myInteger = 42;
        UA_Variant value;
        UA_Variant_setScalar(&value, &myInteger, &UA_TYPES[UA_TYPES_INT32]);
        UA_Server_writeValue(server, dataSet_field_id_, value );
}

我知道

[2019-11-14 14:28:51.467 (UTC+0700)] info/session Connection 0 | SecureChannel 0 | Session g=00000001-0000-0000-0000-000000000000 | WriteRequest returned status code BadNodeClassInvalid

更新变量的正确方法是什么？

opc-ua
1个回答
0
投票

我在open62541问题中提供了解决方案https://github.com/open62541/open62541/issues/3275#issuecomment-554454083

================================================ ======================我在回购中的其他一些示例中环顾四周，发现解决方案如下：1.我需要添加一个变量节点

//node id
UA_NodeId gCounterNodePublisher = {1, UA_NODEIDTYPE_NUMERIC, {1234}};

addVariableNode( UA_Server * server )
{
    UA_UInt64 publishValue = 0xCAFEDEADCAFEBEAF; //0xCAFE
    UA_VariableAttributes publisherAttr = UA_VariableAttributes_default;
    UA_Variant_setScalar(&publisherAttr.value, &publishValue, &UA_TYPES[UA_TYPES_UINT64]);
    publisherAttr.displayName = UA_LOCALIZEDTEXT("en-US", "Publisher Counter");
    publisherAttr.accessLevel = UA_ACCESSLEVELMASK_READ | UA_ACCESSLEVELMASK_WRITE;
    UA_Server_addVariableNode(server, gCounterNodePublisher,
                              UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
                              UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES),
                              UA_QUALIFIEDNAME(1, "Publisher Counter"),
                              UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
                              publisherAttr, NULL, NULL);
}

在addDataSetField中，我们需要使用相同的节点ID配置数据集

addDataSetField( UA_Server * server )
{
    // Add a field to the previous created PublishedDataSet 
    //UA_NodeId dataSetFieldIdent;
    UA_DataSetFieldConfig dataSetFieldConfig;
    memset(&dataSetFieldConfig, 0, sizeof(UA_DataSetFieldConfig));
    dataSetFieldConfig.dataSetFieldType = UA_PUBSUB_DATASETFIELD_VARIABLE;
    dataSetFieldConfig.field.variable.fieldNameAlias = UA_STRING("Server localtime");
    dataSetFieldConfig.field.variable.promotedField = UA_FALSE;
    dataSetFieldConfig.field.variable.publishParameters.publishedVariable = 
    //UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_SERVERSTATUS_CURRENTTIME);
    //UA_NODEID_NUMERIC(0, UA_NS0ID_INT32);
    gCounterNodePublisher;
    dataSetFieldConfig.field.variable.publishParameters.attributeId = UA_ATTRIBUTEID_VALUE;
    UA_Server_addDataSetField(server, published_dataSet_id_,
                              &dataSetFieldConfig, &dataSet_field_id_);
}
  1. 现在棘手的事情是我需要在addPubSubConnection之前调用addVariableNode
    //server init and configuration
    addVariableNode(server);
    addPubSubConnection(server, transportProfile, networkAddressUrl);  
    addPublishedDataSet(server);  
    addDataSetField(server);  
    addWriterGroup(server);  
    addDataSetWriter(server);

现在，我可以将变量设为已发布数据。3.要更新该值，我的解决方案是我们需要在写入/读取该变量时添加回调函数。 （可能我们有另一种方法）

writeVariableNode( UA_Server * server )
{
    //Write a different integer value
    static UA_UInt64 myInteger = 0xCAFEDEADCAFEBEAF;
    UA_Variant myVar;
    UA_Variant_init(&myVar);
    myInteger++;
    UA_Variant_setScalar(&myVar, &myInteger, &UA_TYPES[UA_TYPES_UINT64]);
    UA_Server_writeValue(server, gCounterNodePublisher, myVar);

    // Set the status code of the value to an error code. The function
    //UA_Server_write provides access to the raw service. The above
    //UA_Server_writeValue is syntactic sugar for writing a specific node
    //attribute with the write service. 
    UA_WriteValue wv;
    UA_WriteValue_init(&wv);
    wv.nodeId = gCounterNodePublisher;
    wv.attributeId = UA_ATTRIBUTEID_VALUE;
    wv.value.status = UA_STATUSCODE_BADNOTCONNECTED;
    wv.value.hasStatus = true;
    UA_Server_write(server, &wv);

   //Reset the variable to a good statuscode with a value 
    wv.value.hasStatus = false;
    wv.value.value = myVar;
    wv.value.hasValue = true;
    UA_Server_write(server, &wv);
}

void onReadImpl(UA_Server *server,
               const UA_NodeId *sessionId, void *sessionContext,
               const UA_NodeId *nodeid, void *nodeContext,
               const UA_NumericRange *range, const UA_DataValue *data) {

    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
            "OPCUARuntime::onReadImpl");

    // Write a different integer value 
    static UA_UInt64 myInteger = 0xCAFEDEADCAFEBEAF;
    UA_Variant myVar;
    UA_Variant_init(&myVar);
    myInteger++;
    UA_Variant_setScalar(&myVar, &myInteger, &UA_TYPES[UA_TYPES_UINT64]);
    UA_Server_writeValue(server, gCounterNodePublisher, myVar);

    /// Set the status code of the value to an error code. The function
    // UA_Server_write provides access to the raw service. The above
    // UA_Server_writeValue is syntactic sugar for writing a specific node
    // attribute with the write service. 
    UA_WriteValue wv;
    UA_WriteValue_init(&wv);
    wv.nodeId = gCounterNodePublisher;
    wv.attributeId = UA_ATTRIBUTEID_VALUE;
    wv.value.status = UA_STATUSCODE_BADNOTCONNECTED;
    wv.value.hasStatus = true;
    UA_Server_write(server, &wv);

   //Reset the variable to a good statuscode with a value 
    wv.value.hasStatus = false;
    wv.value.value = myVar;
    wv.value.hasValue = true;
    UA_Server_write(server, &wv);
}

void onWriteImpl(UA_Server *server,
               const UA_NodeId *sessionId, void *sessionContext,
               const UA_NodeId *nodeid, void *nodeContext,
               const UA_NumericRange *range, const UA_DataValue *data) {

    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
            "OPCUARuntime::onWriteImpl");
}

addValueCallbackToVariableNode( UA_Server *server )
{
    UA_ValueCallback callback ;
    callback.onRead = onReadImpl;
    callback.onWrite = onWriteImpl;
    UA_Server_setVariableNode_valueCallback(server, gCounterNodePublisher, callback);
}

主函数中的调用顺序必须是这样的：

    //variable node need to be added before pubsub connection is establish  
    addVariableNode( server_ );

    //Register callback on read/write published data
    addValueCallbackToVariableNode( server_ );
    addPubSubConnection( server_, &transportProfile, &networkAddressUrl);
    addPublishedDataSet( server_ );
    addDataSetField( server_ );
    addWriterGroup( server_ );
    addDataSetWriter( server_ );
    //addVariableNode( server_ );

    //shutdown is taken place inside run once running is false
    UA_StatusCode retval = UA_Server_run(server_, &running_);
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