OPC technology in monitoring and control system (1)

1 creation of OPC technology

OPC (OLE for Process Control) technology is an object link and embedded technology in process control applications, contains a series of industrial automation interface specification.

This technique is to address the application software and a variety of device drivers for the communication of that hardware manufacturers and software developers separate, greatly improving the working efficiency.

With the continuous development of industrial production, due to the expansion of production scale and complexity of the process, industrial control software design face enormous challenges, namely to integrate an increasing number and variety of information.

In the traditional control systems, smart devices and smart device and system software information sharing is achieved through the drivers, the devices from different manufacturers use different drivers, forcing the industrial control software contains an increasing number of underlying communication module; in addition, because relative specific application drivers typically do not support hardware changes, allows industrial control software and hardware upgrades and maintenance is extremely inconvenient. There are at the same time, two customers not on the same device for data read and write because they have different, independent of the driver, at the same time on the same device, you may cause access violation, or even crash the system. OPC technology there is a great way to address these issues. OPC to OLE/COM/DCOM technology, uses the client/server mode for the industrial automation software object-oriented development with a unified standard, the standard defines application Microsoft operating system in the PC-based Automation client to Exchange data between real time. Using this standard, the hardware developer will replace the software developers for their own hardware product development integrated OPC interface program, and software developers may waive development driver work, put more effort into the development of its core product. This not only avoids the development of repetitive, but also improved the system of openness and interoperability.

2 application of OPC technology

OPC is connecting to a data source (OPC Server) and data users (OPC applications) software interface standard.

The data source can be a PLC, DCS, barcode reader and other control devices. With the control system, as the data source of the OPC server can be either and OPC applications running on the same computer, the local OPC Server or on a separate computer running remote OPC server. OPC interface can apply through the network to the lowest control equipment available to the original data as the data consumer (OPC applications) HMI (hardware monitoring interface)/SCADA (supervisory control and data acquisition), batch processing, and other automation programs and even more top historical databases, and other applications, can also be used for the application and a direct connection to a physical device. So the OPC interface is suitable for many systems have a high thickness softness of interface standards. OPC technology innovations are the users the ability to move any visualization or control system and choose any of the hardware (i.e. PC Board) through the OPC together, as shown in Figure 1.

As can be seen from the figure, the OPC standard software bus enables multiple onsite line systems can be integrated, such as PROFIBUS, CANopen network (open control local) network, Device Net (network), etc., can also be an in-depth reflection OPC and fieldbus standardization relations: OPC to provide field bus outside the important additional performance fieldbus field standardization's main goal is rapid, reliable data transfer.

While OPC enables standard communication can achieve such a degree that any OPC Server and application software to run networking will have no problems.

3 OPC technology solutions

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