An error occurred while saving the commentcjrancur commented
Because this can prevent data loss, it should be a high priority. Data loss will be caused without this feature whenever an OPC server loses it's health, and sends all data to the PI interface marked with BAD status. This feature request will prevent extended periods of data loss, in cases where an unhealthy OPC server marks all data from a DCS system as bad. The OPC/UA interface has a default setting that requires 80% of data from each interface to be of good quality, or else it marks the interface as being in "CONNECT/NODATA" state. That setting can be lowered, but if it is lowered to 0, it will cause excess resource usage at the PI interface hardware and network level. The percent good quality limit, if not reached, will force the interface to shutdown, despite interface redundancy. Because the bad tags are not ever rechecked, the interface does not restart again even after all data returns to good status when the OPC server returns to health. This delay in PI interface restart can cause data loss over large numbers of PI tags, and the period of data loss can be extended because problem notifications and interventions are required before the interface can be restarted.
Looking for more inputs on how to determine what the last good value is (was). While it’s simple to say a numeric value is good, but what if it’s a non-sensical numeric value like 1000 for temperature? It is also possible to the source system to send out status like NoData. How should that be interpreted? Please provide your inputs.