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Simultaneously HDA Interfaces instances running number?

Diego Monroy

 

Hello,

I am interested in determining the exact number of multiple instances of the HDA interface that can run simultaneously. In the following link:

https://docs.aveva.com/bundle/pi-interface-for-opc-hda/page/1012033.html

The article mentions that "is designed to run multiple instances of the interface simultaneously." But there is no information on how many or what order of magnitude this number can be, so I need to know if you can only have 10, 50, 100, or 500, etc. instances. I appreciate any comments you may have on this matter.

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    Hello ​ ,

    there is no exact number for the amount of interface instances you can run on a single Interface node. Technically you will be limited by the machine resources. I am not 100% certain but believe to remember that PI Interfaces are sold as "Node License" which means that you need one license per Interface node you are operating.

    What would be the reason for creating a second instance of a PI Interface?

    Could be that there is multiple data sources i.e. OPC HDA Servers you want to connect, and I am not talking about redundant OPC servers. OPC supports grouping of tags. A group usually uses a certain scan rate and the suggestion is to assign up to ~ 800 tags per group. When there is more tags to be scanned at the same sample frequency you could easily create a new group. As far as PI Interfaces are concerned, they can easily handle a larger amount of tags but when running into performance issues, you may want to create another interface instance and distribute tags between these 2.

    I have seen installations with up to 5 or 6 instances of a certain type but wouldn't know why one need more than 10 instances.

    What is the amount of PI OPC HDA Interface instance you like to operate on a single interface node and what's the reasoning behind?