There are three main aspects of continuous data collection and presentation:
History collection is a function used in the DeltaV Explorer and Control Studio to define the module parameters or node parameters to be monitored and stored in the DeltaV Continuous Historian. History collection is an integral part of a module. If you copy a module, the new module includes the defined history collection. Library module templates include history collection, which can be modified by the user.
The DeltaV Continuous Historian allows high-volume data capture of time-associated parameter values and efficient storage of these values to disk.
Each workstation with a DeltaV Continuous Historian historical data server component installed has a Primary storage area that holds a collection of historical data sets. One active historical data set receives history samples from the real-time history stream. Zero or more current historical data sets may also exist in Primary storage. These data sets are former active historical data sets that have been completed by hitting the time or size limit rules. The collection of active and current historical data sets comprise the contiguous recent historical data that is still online.
The Primary storage area may also contain zero or more extended historical data sets that have been placed back online through the use of the Continuous Historian Administration tools. These data sets may be for any history tags for any period of time, without continuity with the active and current historical data sets.
DeltaV Process History View is the application that is used to display real-time and historical data from the Continuous Historian subsystem as well as from the DeltaV Event Chronicle, a subsystem that stores system events and alarms. Module and node trends are plotted on a graph, and events are displayed in a tabular grid format. You can customize the Process History View.
You must download the setup data for each workstation that has a Continuous Historian subsystem enabled – using the DeltaV Continuous Historian, the Advanced Continuous Historian, or OSIsoft PI Server – for Process History View to display the historical data.
The History Web Service (HWS) provides a set of web methods that client applications can use to interact with the DeltaV Batch Historian. For information on installing HWS, refer to the DeltaV History Web Service online help file, HWS.chm, on the DeltaV installation disk #4 in the \DV_Extras\WebServices\ folder.