Trend recording offers a long-term acquisition of data. With the help of a trend recording, values of IEC variables are acquired and persistently saved in a database. Historical data are retained so that a trend can be read from the data. The database is located on the controller and is filled up at runtime. Trend data can be displayed by a visualization, which reads out the database and visualizes the records.
Depending on the amount of data that is recorded and the performance of the controller, it may happen that a timeout expires during trend recording operations. This is detected as an exception error.
Before you stop the controller or perform a download (execute the Online change command), stop the trend recording process to save the trend data to the database.
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NOTICE |
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LOSS OF DATA |
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Stop the trend function and save the trend data before changing state of the controller from the run state. |
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Failure to follow these instructions can result in equipment damage. |
This function is not available for all supported controllers. Consult the Programming Guide specific to your controller as to whether it supports trend recording.
