Retrieve data even it's not changed on OPC server
Currently Connector configured to rertieve event on change and not based on a scan class like interfaces.The Connector suscribes to the changes, and when a change comes in to the server, the data will be sent to PI connector. We need option to retrieve the data every certain minutes even data is the same and is not changed on OPC server.
We understand that for slow changing points, values might not change often and thus there is a need to collect values at certain time intervals as opposed to on change. However, scanning at frequent intervals leads to increased load on the server and thus can lead to performance degradation. We are discussing how best to solve this problem with PI Connector for OPC UA.
This feature is very important to us as missing one event in case of a Setpoint which gets only changed infrequently, would lead to have wrong information in PI until the Setpoint is changed again (might be weeks or month). As we use the PI System for GMP BatchReporting where setpoints play an important role, wrong data would invalidate our documentation. So we would like to introduce a "Scan every x seconds" on a Tag basis. Maybe in the TagNamingWorkSheet used in TagsOnly Mode. By specifying the scan rate per Tag the additional load / traffic could be limited to where needed.
At least at Startup the connector should poll all the data one time.
We have a requirement to Test existing PI Tags getting data from OPC UA Server through PI Connectors (188.8.131.52). Since the OPC UA Server is also in Testing phase so no new data can be generated on it. What would be the best way to test my connection if the Status, Timestamp and Value of OPC UA Variables doesn't changes?
Even getting one event from OPC UA Server to the corresponding PI Tag will result in successful connection.
We have same issue with that.
Most times it makes sense to ASK OPC Server to get actual values for some specific tags just to check, if connnection is alive or broken.
It is not unusual that something is going wrong on the connection and we can't see if values are reliable or not.
If I understand this correctly, the solution provided by PI Connector for OPC UA version 1.3.x requires you to maintain a csv file with all your opc server tags. That is impossible when your opc server have over +100K tags.
Gabriel Verreault commented
This functionality is available in the PI Connector for OPC UA version 1.3.x - available on the Tech Support website. Look for DataChangeTrigger in the User Guide. It explains how to set a subset of tags to update everytime the timestamp updates. In conjunction with SamplingInterval, you can define the data retrieval rate, and when is the data going to be sent to PI.
Adrien LACOTE commented
This functionality is necessary for Industry, we had it using one concurrent product, I hope you will implement it asap.
David Benco commented
Since it also has to do with unchanged data updates, allow "exception reporting" capabilities where a tag can mimic trend-like behaviors, which are useful for things such as Set Points.