Glossary · Industrial communication
OPC
Also known as: OLE for Process Control, Open Platform Communications
German: OPC
In industrial communication, OPC is the family of interoperability specifications maintained by the OPC Foundation for exchanging data between automation devices and software. The name originally stood for OLE for Process Control; today it covers OPC Classic and OPC Unified Architecture (OPC UA).
- Industrial communication
- Standards
In one sentence
OPC is the OPC Foundation's family of interoperability standards for industrial data exchange, covering OPC Classic and OPC UA.
Example
A historian collects values from controllers of three vendors through OPC servers instead of three proprietary drivers.
How it applies
- Engineering: OPC decouples client applications (SCADA, historian, MES) from device-specific protocols. Servers translate controller data into a standard interface.
- Migration: Many plants run both generations: OPC Classic on Windows systems and OPC Unified Architecture (OPC UA) for new connections. The generations aren't directly compatible; wrappers or gateways bridge them.
- Security: OPC Classic relies on Windows DCOM, which is difficult to secure across networks. OPC UA has built-in security.
- Documentation: The documentation team always names the generation and specification (for example OPC DA, OPC UA with a specific companion specification), because "OPC interface" alone doesn't tell integrators whether two products can talk to each other.
OPC Classic vs. OPC UA
OPC Classic consists of separate COM/DCOM-based specifications for current data, history and alarms. OPC UA unifies these in one platform-independent architecture with an Information model, services and security.