ClearSCADA supports these different types of Trend:
- Pre-Configured Trends—These Trends are represented in the database by Trend database items. Pre-Configured Trends can display multiple traces and may combine current, raw historic and processed historic data on a single display. The configuration of these Trends is stored in the ClearSCADA database, and is retained when you close the Trend display.
- Ad Hoc Trends—ClearSCADA supports two types of Ad Hoc Trend:
- ‘Standard’ Ad Hoc Trends are generated by ClearSCADA on command and are not stored in the database. You can display a ‘standard’ ad hoc Trend by selecting the Display Current Trend or Display Historic Trend pick action (see Display a Trend in Run Mode). ‘Standard’ Ad Hoc Trends are temporary, and any configuration is lost when the Trend display is closed.
- ‘Custom’ Ad Hoc Trendscan be configured using ClearSCADA's proprietary specification language, TrendSpec. The configuration of these Trends is stored in the ClearSCADA database. Usually, ‘custom’ Ad Hoc Trends are accessed via hyperlinks on Mimics.
The trace(s) on Trends may display either:
- Current Data—A trace that updates according to the current value of the point or master station accumulator. When the Trend is closed, the data displayed on the Trend is disregarded and cannot be re-displayed on the Trend.
- Historic Data—A trace that displays historic data that has been logged by the ClearSCADA server into the Historic database (providing that Historic logging is enabled). Usually, there are a limited number of points and/or accumulators that have Historic logging enabled, as historic logging uses disk space on the ClearSCADA server.
When you display historic data on a Trend, the Trend displays the historic data that was logged during a specific time period. You can view the historic values either side of this period by panning the Trend (see View Earlier or Later Values on a Trend).
The configuration of the point object determines if the ‘standard’ ad hoc Trend will display Raw Historic or Processed Historic data (see Defining Historic Details for a Point).
To create and configure Trends in ViewX, you need to log on via a User Account that has the Configure permission. For more information, see Configuring Trends, and Using TrendSpec to Produce Ad Hoc Trends.
To view a Trend, you need to access the Trend via a ViewX or WebX client (see Using Trends).