When you open the trend analysis, the default time range is used as the basis for scaling the X-axis. The currently displayed time range is shown in the trend analysis toolbar.
This default time range is a user-specific setting that you can configure in your user profile, on the Preferences tab.
When you open the trend analysis, the start and end dates of the displayed time range are calculated based on the current date, going back in time:
Start Date = Current Date - Default Time Range
Adjust the time range
To change the time range for the trend analysis, click in the time range field.
An advanced dialog box opens for setting the time range.
By default, the dialog box opens in the monthly view, displaying two months. If you want to select longer time periods, you can use the icon buttons in the upper-left corner to switch to a yearly or decade view.
To select a specific time period, you have two options:
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Selecting with the mouse:First, click the start date on the calendar, and then click the end date. The selected time range between these two days is highlighted in green.
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Entering the Date:Enter the start date in the Start field and the end date in the End field. The color highlighting in the calendar will be updated accordingly.
However, you can also select one of the predefined time ranges. To do so, simply click the button you want. The available options are:
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Last week
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Last month
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Last 6 months
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Last year
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Last 2 years
The time periods always extend from the current date into the past.
The button <All data> is only available if at least one trend has been loaded. When you click on <All data>, the system searches for the oldest data point in the loaded trends and sets its date as the start date. The current date is entered as the end date.
After selecting the time period, click on <Apply>. The dialog box closes, and the time period is now plotted on the X-axis. For the preset time ranges and <All data>, a double-click is also sufficient to apply the time range and close the dialog box.
The newly selected time range remains valid as long as the trend analysis is open. If you close the Trend analysis tab and reopen it, the default time range (as specified in your user profile) will be restored.
If no data is available for a selected time range, an error message will be displayed.
Special considerations when making a selection by <All data>
If you add additional trends after selecting the time period for <All data>, the current time range remains unchanged, even if the new trends include older data. The time range is adjusted only after you click <All data> again.
With trend filters, the filter signal is used to determine the time range instead of the filtered trend. This means that if the filter signal has been recorded for longer than the trend of a sensor or component to which the filter is applied, then the start date for the trend analysis is the oldest data point in the filter signal, not the one in the trend.