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Understanding OPC and OPC UA

Jun 29, 2024

Understanding OPC and OPC UA

Introduction

  • Objective: Explain OPC and where it fits in the architecture compared to MQTT.
  • Sponsored by: EMQX (enterprise broker).
  • **Key Points: **OPC is not considered an IIoT protocol by many engineers, despite the OPC Foundation's stance.

What is OPC?

  • Full Form: OLE for Process Control (Object Linking and Embedding for Process Control).
  • Origin: Derived from Microsoft's OLE technology in the 90s for application interoperability within Windows OS.
  • Purpose: Facilitate industrial process control by allowing different software to communicate.
  • Management: Standards governed by the OPC Foundation, a consortium with members from various companies.
  • Key Members: Beckhoff, Microsoft, Rockwell Automation, etc.

How OPC is Used

  • Example: Manufacturing floor with different PLCs (e.g., Beckhoff, Rockwell, Siemens).
  • Common Solution: Use a tool like Kepware’s KepServerEX to connect and manage PLCs.
  • Process:
    • Purchase appropriate drivers for each PLC type (e.g., Beckhoff, Allen-Bradley, Siemens).
    • Create a namespace in KepServerEX to organize tags and information.
    • Expose this namespace via OPC UA standard to any OPC client.

OPC Standards

  • OPC Classic: Based on COM and DCOM tech from the 90s and early 2000s.
  • OPC UA: Updated standard incorporating modern technologies.
  • **Challenges: ** OPC UA carries technical debt from OPC Classic, complicating integration.

Why OPC UA is Not the Future of IIoT

  1. Technical Debt: Remnants of OPC Classic make it hard to use.
  2. Commercial Focus: Corporations in OPC Foundation aim to sell products rather than true interoperability.
  • Example: 600 members, yet their products often don’t seamlessly interoperate.
  1. Bureaucracy: Heavy bureaucracy within the OPC Foundation reduces efficiency.

What Should You Do?

  • Homework: Compare OPC Foundation’s website and EMQX’s website.
  • EMQX Benefits:
    • Open source.
    • Massively scalable (supports millions of IoT devices).
    • Cloud-native.
    • Elastic capacity for scaling.

Conclusion

  • Summary: OPC was created for process control but has limitations in IIoT applications due to technical debt and commercial interests.
  • Next Steps: Future videos will delve deeper into OPC architectures and practical use cases.
  • Acknowledgment: Thanks to EMQX for sponsoring the video series.

Full transcript