OPC
Open Platform Communications
Frustrated with OPC downtime?
What is Open Platform Communications (OPC)?
Open Platform Communications (OPC) is a series of standards and specifications for industrial telecommunication. Originally known as OLE for Process Control, OPC has evolved to facilitate interoperability in industrial automation by providing a common interface for different hardware and software systems to communicate. The OPC standards are developed and maintained by the OPC Foundation, which ensures that various automation systems can work together seamlessly.
OPC DA
OPC DA (Data Access) is one of the primary specifications within the OPC standard and is designed to facilitate real-time data communication between different devices and applications in industrial automation systems. It uses a client-server architecture based on Microsoft COM/DCOM technology which ties it to the Windows platform. From a security standpoint, OPC DA has limited features and relies on the underlying DCOM mechanisms, which can be complex to configure securely. OPC DA uses a flat, tag-based structure, representing data points with tag – this simple structure however lacks the ability to model complex data relationships.
OPC UA
OPC UA (Unified Architecture) is a comprehensive, platform-independent industrial communication protocol designed to enhance interoperability and security in automation systems. It represents a significant evolution from earlier OPC specifications like OPC DA (Data Access). OPC UA is platform-independent, using standard internet protocols, making it suitable for a wide range of operating systems and devices. It includes robust security measures such as user authentication, message encryption and data integrity checks, using modern standards for secure communication and supports a rich, object-oriented data model, enabling the representation of complex data structures and hierarchical relationships, which better reflect real-world systems.
What is an OPC Server?
An OPC server is a software application that acts as an intermediary between data sources (such as PLCs, RTUs and databases) and client applications (such as SCADA systems, HMIs, or other data analytics tools). The primary role of an OPC server is to collect data from various devices and make this data available in a standardized format to OPC clients.
Commonly Asked Questions about OPC DA and OPC UA
OPC DA and OPC UA are both part of the OPC standards but differ significantly in their design and capabilities.
OPC DA focuses on real-time data access within industrial automation systems and uses a client-server architecture based on Microsoft COM/DCOM technology, which ties it to the Windows platform and limits cross-platform compatibility.
OPC UA is a comprehensive framework that unifies various OPC specifications and supports both client-server and publish-subscribe models. OPC UA is platform-independent, using standard internet protocols, making it suitable for a wide range of operating systems and devices.
OPC stands for Open Platform Communications.
Explore other industrial protocols
MAC Automation
MAC Engineering