I am building a PI 2016 R2 system. I have a Novatech D/3 control system, version 14 and am using the PI Interface for GSE D/3 DBA interface. Is there any standard practice or guidance for defining scan classes?
There are no specific scan class requirements for the PI Interface for GSE D/3 DBA, so I would suggest starting by placing all of your tags in a single scan class, set at your desired update frequency.
From there you can view the performance and adjust as needed. You can use the UniInt health points to see your interface's performance. In particular, you want the "Scans Skipped" health point for your scan class to equal zero. You can use your scan class' Performance Point in order to see how long your scans take. These tags can be created from the Health Points and Performance Points tabs in the Interface Configuration Utility.
If scans are being skipped you can increase the scan time or distribute the tag load by creating additional scan classes or interface instances.
Matthew is right, but I do want to add that the GSETID3 Interface does not support advise scanning. You could get the D/3 OPC Server installed on two of your DCMs (with appropriate licensing) and make use of the PI OPC DA Interface, which does support advise scanning for all of your DEV/DIN/DOT scanning needs. I would recommend this anyway if you have the D/3 OPC Server available as I've found the PI OPC Interface to be much more reliable than GSETID3. The only big difference in PI point configuration is including the PCM name in the instrumenttag, i.e. EPN.TIC1000.AI_0.AI_MEAS instead of TIC1000:0:AI_MEAS.
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