我目前正在尝试使用名为 open62541 的 OPC UA 实现发布日期时间值和温度值。
为此，我一直在使用来自 open62541 github 存储库的测试示例，因为它已经发布了当前日期时间。我试图为温度值添加另一个 DSF(DataSetField)，就像它与日期时间一起显示的那样。但它不会发布它。
以下代码片段显示了我如何定义添加 DataSetFields 的方法：
/**
* **DataSetField handling**
*
* The DataSetField (DSF) is part of the PDS and describes exactly one published
* field. */
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);
dataSetFieldConfig.field.variable.publishParameters.attributeId =
UA_ATTRIBUTEID_VALUE;
UA_Server_addDataSetField(server, publishedDataSetIdent,
&dataSetFieldConfig, &dataSetFieldIdent);
}
static void
addDataSetFieldTemperature(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("Temperature");
dataSetFieldConfig.field.variable.promotedField = UA_FALSE;
dataSetFieldConfig.field.variable.publishParameters.publishedVariable =
UA_NODEID_NUMERIC(0, 50);
dataSetFieldConfig.field.variable.publishParameters.attributeId =
UA_ATTRIBUTEID_VALUE;
UA_Server_addDataSetField(server, publishedDataSetIdent,
&dataSetFieldConfig,
&dataSetFieldIdent);
}
在主函数中，然后我调用这两个方法将它们添加到 PDS（PublishedDataSet）：
addPubSubConnection(server, transportProfile, networkAddressUrl);
addPublishedDataSet(server);
addDataSetFieldTemperature(server);
addDataSetField(server);
addWriterGroup(server);
addDataSetWriter(server);
温度值是一个简单的双精度值，那么我在这里做错了什么？也许错误在订阅的客户端应用程序中？
为了订阅已发布的值，我还使用了 github 上的示例（文件名为 tutorial_pubsub_subscribe.c），我正在尝试按如下方式解析值：
/* Loop over the fields and print well-known content types */
for(int i = 0; i < dsm->data.keyFrameData.fieldCount; i++) {
const UA_DataType *currentType = dsm->data.keyFrameData.dataSetFields[i].value.type;
if(currentType == &UA_TYPES[UA_TYPES_BYTE]) {
UA_Byte value = *(UA_Byte *)dsm->data.keyFrameData.dataSetFields[i].value.data;
UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
"Message content: [Byte] \tReceived data: %i", value);
} else if (currentType == &UA_TYPES[UA_TYPES_DATETIME]) {
UA_DateTime value = *(UA_DateTime *)dsm->data.keyFrameData.dataSetFields[i].value.data;
UA_DateTimeStruct receivedTime = UA_DateTime_toStruct(value);
UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
"Message content: [DateTime] \t"
"Received date: %02i-%02i-%02i Received time: %02i:%02i:%02i",
receivedTime.year, receivedTime.month, receivedTime.day,
receivedTime.hour, receivedTime.min, receivedTime.sec);
} else if(currentType == &UA_TYPES[UA_TYPES_UINT16]) {
UA_UInt16 receivedTemp =
*(UA_UInt16 *)dsm->data.keyFrameData.dataSetFields[i].value.data;
UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
"Message content: [UA_UInt16] \t"
"Received temperature: %i",
receivedTemp);
}
有什么建议么？非常感谢您，如果您需要有关此问题的更多详细信息，请告诉我，我将进一步编辑问题！
编辑：如果您想查看整个示例代码，请查看以下链接：对于发布应用程序： https ://github.com/open62541/open62541/blob/master/examples/pubsub/tutorial_pubsub_publish 。C
对于订阅应用程序：https ://github.com/open62541/open62541/blob/master/examples/pubsub/tutorial_pubsub_subscribe.c