User Manual

Operating Reference
Trends
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NOTICE
Validated
Projects
Specific critical environments (for example, pharmaceutical installations and
processed) require a high degree of safety and traceability of all operational
workflows and user activities. A validated plant can lose its validity or must be
revalidated by adding or losing BACnet objects. Therefore, do not use this
function, or do not enable it in the application rights.
3.6.4 Online Trends
Online trends record real-time values from your plant and display them graphically
in a Trend View. The data values are sent to the trend application upon each
change of value. The measured values are temporary and can be stored for later
queries continuously in the Trend database using online Trend log objects. Online
trends can be used for real-time visualization of one or more process variables,
usually for analysis or diagnosis.
You can create an online trend in situations where the room temperature is too low
and record the temperature data for a specific time period. You can further analyze
the measured values in a trend curve directly on the management station.
Record Online Trend Data
Trend data are uploaded
continuously to the management
station and are not saved in the
automation station.
NOTE:
An uninterrupted site connection with the management station is required.
Measured values may be irretrievably lost when the site is interrupted during data
recording. Therefore, online trend is not well suited for long-term secure data
recording.
3.6.5 Predicted Trends
Desigo CC can use time series to predict future values. For example, predicting
weather for the upcoming days by reading weather forecast data from a weather
service. Predicted future values display in a graph using the Trends application.
Many predicted trends can be combined with other trended objects/properties.
Also, forecast data can be combined with the values of the same parameter saved
in the history database, as well as, can be compared with real-time data. For
instructions, see Additional Predicted Trends Procedures [➙ 138].
3.6.6 Trend Data Storage
Recorded trend data can be stored in three different locations:
● Offline Trendlog Objects: Offline trend data is saved in the automation station.
● Online Trendlog Objects: Contains the online trend data recorded and saved in
the management station.
● Archived Trend Database (not in version 2.0): Contains all recorded trend data
moved previously to the archive database.
64°F
64°F
64°F
Trend DB
Management Station
Automation
Station