Determine if the real-time window is configured appropriately for a swinging door deadband

To determine if the real-time window is configured correctly for a swinging door deadband, look at the number of data values that are forced to be stored while the system waits for the next valid data point to make the filtering calculation.

The SysRateDeadbandForcedValues system tag counts the number of "extra" points forced to be stored as a result of an insufficient real-time window for swinging door storage. Also, you can determine the number of points forced to be stored for an individual tag by executing a query that uses the full retrieval mode and specifies a quality detail of 2240, which indicates that these points were stored because of an insufficient real-time window.

If you find a large number of forced storage points, you can either reconfigure the tag to use delta storage or increase the real-time window.

Note: The first two points received for a tag configured for swinging door storage are always stored.

Also, use caution when setting the real-time window to accommodate a swinging door deadband.

• If your system has a large tag count or high data throughput, increasing the real-time window will increase the memory requirements for storage, because the storage system will have to process more data as real-time data, which is more resource-intensive than the storage of late data.

• If you increase the real-time window and you apply a swinging door deadband to a slow-changing tag, the amount of storage space required increases because the tag value is forced to be stored more often than if you used delta storage with no deadband.