Yes—most modern OPC communication uses Ethernet as its primary transport medium. OPC (OLE for Process Control) started in the 1990s as a Windows-based technology relying on Microsoft’s COM/DCOM framework, typically over Ethernet-based industrial networks. While early implementations could run across different connection types, it quickly became the standard because of its speed, reliability, and broad adoption in industrial automation. Today, whether you’re dealing with OPC DA (Data Access), OPC HDA (Historical Data Access), or OPC UA (Unified Architecture), Ethernet underpins the majority of deployments.

Why Ethernet Matters for OPC

Ethernet provides the backbone that makes OPC scalable and practical in real-world industrial environments. Unlike legacy fieldbuses, Ethernet allows OPC servers and clients to operate across local networks and even securely across the internet. This means automation systems, historians, and SCADA platforms can exchange data quickly without needing proprietary cabling or specialized gateways. OPC UA in particular was designed with Ethernet in mind, allowing cross-platform communication while supporting encryption, authentication, and role-based security.

OPC Variants and Ethernet Use

• OPC DA / HDA / A&E (Classic OPC): These rely on DCOM for communication. While DCOM itself can run on different transports, in practice, it is almost always implemented over Ethernet within Windows networks.
• OPC UA: This is the modern standard and was engineered to take full advantage of Ethernet. It uses TCP/IP for communication and can also run over HTTPS or WebSockets, making it versatile for both on-premises and cloud integrations.
• OPC Tunneling Solutions: To simplify firewalls and IT policies, many tunneling tools package OPC communication into a single TCP port—again, over Ethernet.

Real-World Application

Imagine a manufacturing plant with PLCs, sensors, and an MES system. Ethernet provides a high-speed local network. OPC servers expose machine data, while OPC clients consume it for dashboards, alarms, and analytics. Because it’s Ethernet-based, the system is flexible, easy to scale, and integrates with higher-level IT systems.