What are the functional requirements for an OPC server?

It is neither pure hardware nor pure software; it is a set of standards and specifications. The function of an OPC server is to exchange data with lower-level devices, and this involves a large number of communication programs and data storage programs. Then a standard OPC interface is provided for use by other software. Once the procedures are standardized, other software vendors only need to develop programs that interact with the server, without having to create separate hardware drivers for different hardware devices. It reduces the workload and makes it easier to use. Below is a standard description of OPC. It’s a bit long, but it’s very helpful for understanding OPC: OPC is an abbreviation for OLE for Process Control, which means applying OLE to the field of industrial control. OLE stands for Object Linking and Embedding; with the release of OLE 2, its scope has gone far beyond this original concept. Today’s OLE incorporates many new features such as unified data transfer, structured storage, and automation; it has become a standard that is independent of computer languages, operating systems, and even hardware platforms, representing a further extension of the concepts of object-oriented programming. OPC is built on top of the OLE standard, and it provides a standard data access mechanism for the field of industrial control. The field of industrial control makes use of a large number of field devices; before the emergence of OPC, software developers had to create numerous drivers to connect to these devices. Even if the hardware supplier makes minor changes to the hardware, the application may need to be rewritten ； At the same time, since the drivers for different devices or even different units of the same device can vary, it is difficult for software developers to access these devices simultaneously in order to optimize their operation. Hardware suppliers are also trying to solve this problem; however, due to the different needs of various customers as well as the existence of various data transmission protocols, there has yet to be a complete solution. Since OPC was introduced, this problem has finally been solved. The OPC specification consists of an OPC server and an OPC client; its essence is to establish a set of complete \"rules\" between hardware suppliers and software developers. By following these rules, data exchange remains transparent for both parties – hardware suppliers need not consider the various requirements of applications or transmission protocols, while software developers do not need to understand the workings and operations of the hardware. The advantages of OPC are obvious: hardware suppliers only need to provide a set of programs that comply with the OPC Server specifications, without having to consider the needs of engineers. Software developers do not need to rewrite a large number of device drivers. Engineers now have more options when selecting equipment. l OPC expands the concept of devices. As long as they comply with the OPC server standards, OPC clients can exchange data with them without needing to know whether the device is a PLC or a meter; even when OPC standards are implemented in database systems, OPC clients can still facilitate data exchange with them. Scope of application for OPC: The ultimate goal of OPC designers is to establish a set of data transmission standards in the industrial sector, and they have developed a series of plans for its development. The existing OPC specifications cover the following areas: online data monitoring. It enables efficient and flexible data reading and writing between applications and industrial control devices. Alarm and event handling. It provides a mechanism to send notifications to OPC clients in the event of an exception occurring in the OPC server, as well as when events set by the OPC server arrive. Access to historical data. Methods for reading, operating on, and editing historical databases have been implemented. Remote data access. Leveraging Microsoft’s DCOM technology, OPC enables high-performance remote data access. Other functions that OPC will implement in the near future include security, batch processing, and access to historical alarm event data. The designers of OPC followed these principles when creating it: ease of implementation. Flexibly meet the diverse needs of customers. Powerful features. Efficient operation.

The OPC server can upload factory data to the factory information management system. In device production, process data is uploaded to the real-time database using OPC; the real-time database then provides this process data to the Manufacturing Execution System (MES) and the enterprise’s management departments, with data transmission generally occurring in a one-way manner.