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Roger Palmen

I've written this blog post many times in my head, as frequently new issues or limitations of the OPC-UA options for PI pop up. After my latest learning i decided to write this down so that some awareness is created on the limitations. I always hoped OPC-UA would bring benefits over the classic OPC-DA connectivity, but as things stand to date, i have severe doubts. And especially as there is no clear vision / roadmap on datacollection i think this is a really big problem for PI. If we cannot collect data into PI scaleable and reliable, the future of PI is doubtful. OPC-UA should be the only protocol one would need in a modern environment, but PI does not provide a proper way to connect to OPC-UA


Below a brief list of major issues and limitations i've encountered while dealing with OPC-UA.

  • Connector-level redundancy / failover is not supported by Gen2 OPC-UA Collector, only by Gen1 OPC-UA connector
  • Source-level redundancy / failover is not supported by either Gen1 or Gen2 OPC-UA Connectors, except for 'transparent' source failover supported by the OPC-UA server (which i have not seen anywhere)
  • Failover only fires when connection to ALL datasources is lost
  • PI Adapter for OPC-UA does not support redundancy / failover (yet...)
  • PI Adapter for OPC-UA is not scaleable when used with PI Data Archive, as using PI Web API endpoint adds limitation of 100K data streams
  • Routing feature of Gen2 connector does not really do routing all data sources are combined into a single data stream to the destination(s)
  • Tag renaming on PI Connector Gen1 and Gen2 cannot be done without data loss
  • Advice only mode leaves slowly updating data stale and/or incorrect

And then there is a long list of defects and functional limitations to add to this.

Parents

  • Thank you for inquiring and bumping up this thread. If you're looking for failover capabilities and buffering functionality, AVEVA Adapter for OPC UA should be suitable for your needs. The latest version of the adapter offers both server-level and client-level failover. As for buffering, in the event that your adapter's connectivity to the data endpoint (whether it be Edge Data Store, AVEVA PI Server, AVEVA Data Hub, or any combination of those three) is lost, the adapter will buffer data for as long as it takes to reestablish a connection or until you run out of disk space. That being said, I would like to hear more about your specific architecture and data throughput expectations to ensure that this is the best fit for you.

Comment

  • Thank you for inquiring and bumping up this thread. If you're looking for failover capabilities and buffering functionality, AVEVA Adapter for OPC UA should be suitable for your needs. The latest version of the adapter offers both server-level and client-level failover. As for buffering, in the event that your adapter's connectivity to the data endpoint (whether it be Edge Data Store, AVEVA PI Server, AVEVA Data Hub, or any combination of those three) is lost, the adapter will buffer data for as long as it takes to reestablish a connection or until you run out of disk space. That being said, I would like to hear more about your specific architecture and data throughput expectations to ensure that this is the best fit for you.

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