Learn about future data in Data Archive

Future data is data associated with a future time stamp. Data Archive 2015 allows storage and retrieval of data with time stamps beyond current time, allowing you to store data within a time range of January, 1970 through January, 2038. With Data Archive 2015 you can capture and analyze data with future time stamps, and use PI visualization tools to graphically create possible forecasts or predictions for your business. You may store and use this forecasted data to predict resource requirements or maintenance activities, find differences between predicted and actual production yields.

Difference between historical and future data

Prior to version 2015, Data Archive only supported data in real time, not future data. This data is typically time-series data collected in real time, and appended to the end of data streams at some regular frequency or sampling interval. The data is effectively stored in time-segmented archive files. With Data Archive 2015, this type of time-series data is differentiated from future data in the way that the PI point is defined, as well as in the way the PI point data is stored and accessed.

Typically, future data is generated over a specific time range, for example, a day or week ahead of the current time, and is periodically refreshed when a new set of predictions becomes available. The refresh interval is typically shorter than the forecast range, so that data from the prior forecast can be either truncated before new values are appended, or overwritten. Interfaces can set an appropriate mode (with which data is sent to Data Archive) to append new forecasts or overwrite an existing forecast with a new forecast. Most interfaces can send the data in a mode to replace the existing forecast values. This allows the data archive to store the newest value of each refresh of a forecast, thereby keeping a useful record of the most accurate forecasted values. These data forecasts can be compared against actual measurements either visually (for example, using graphical PI trends) or analytically (for example, using PI DataLink spreadsheets). Preserving the history of your forecasts may also be useful for model optimizations and "what-if" analyses.

Future time stamp format

Data Archive stores time stamps in coordinated universal time (UTC) format in order to conform to a single reference time. All future time stamps reflect the DST settings as defined in the local time zone for the client computer. For each time zone, current DST settings are considered valid until the local authorities change them. Measured data that originates in another time zone is not considered future data.

You can populate future PI points with data that is time-stamped prior to current time: Data Archive allows you to write future PI point values anywhere in the UTC time range (1970-2038).