The Trends application allows you to work with trends that are recurring samples of data. In order to view the Trends application, you must have Show rights. Any change in the application rights is applicable only after a re-login or refresh.
Trends are of two types, online and offline.
Online Trending: In case of online trending, the trend data are uploaded continuously to the management station and are not saved in the automation station. Online trends record real-time values from your plant and display them graphically in a Trend View. The data values are sent to the Trends application upon each change of value. In case of online trending, an uninterrupted site connection with the management station is required. The measured values can be irretrievably lost when the site is interrupted during data recording. Therefore, online trend is not well-suited for long-term secure data recording. They can be used for real-time visualization of one or more process variables, usually for analysis or diagnosis purpose.
Offline Trends: In the case of offline trending, the trend data is saved locally to the trendlog object in the automation station and thereafter, uploaded to the management station either automatically or manually. The offline trend data is recorded and saved by the trendlog objects even when the management station is not connected. The automatic and manual transfer to the management station is done in the following situations:
Automatic:
- When the number of defined entries is reached
- When the maximum buffer size is reached
Manual:
- When the data transfer is triggered by a user in the management station
The precision for a 64 bit value is supported till 2E49 (15 digits). GmsBitString64 data type is not supported.
Trends in the Flex Client allow you to view trend charts, search for trend objects, start and pause trend data display, create and modify a trend view definition, define the Settings, delete a trend view definition and an online trend log object, and view quality information and missing data.
This section provides background information on Trends in the Flex Client. For procedures or workflows, see the step-by-step section.
Trends Workspace – Tile View
Trends are located in the Application View under Applications > Trends.
In System Browser:
- When you select Trends, the Trend tab displays all the related trend objects such as offline trends, online trends, and trend view definitions in a tile view.
- When you select a particular sub folder, the Trend tab displays all objects present in that sub folder.
You can add new trends or search for existing trends from the tile view.
On clicking 
, the Settings menu displays from which you can access the Trend Settings dialog box. This dialog box provides options to define the settings which are applied to online trend log objects, offline trend log objects and trend view definitions.
Trend Settings
The Trend Settings dialog box allows you to define the settings, which are applied to online trend log objects, offline trend log objects and trend view definitions. In case of trend view definitions, these settings are applied only during creation of new trend view definitions.
NOTE:
Trend settings are saved per user and display the user-specific settings.
1 | Data Accuracy | Displays the number of samples per series, based on the selection anywhere between Loading Fast to High Resolution. By default, the number of samples saved is 100. |
2 | Default time period | Allows to specify the time range, for which the trend data displays in the Trend View. |
3 | Data status indication | Select Enable to display the quality indication area of rectangle shape on the Trend View. The area is highlighted with red color, in order to indicate a quality issue (a problem with the data point). |
Trends Workspace – View Mode
The view mode allows you to view the complete chart preview of the selected trend view definition, online or offline trend log objects.
1 | Legend | Displays information on the objects present in the trend view definition. You can specify the type of information to be displayed by clicking the Layout Setting Depending on the selected Text Representation the following type of object information displays in the legend: |
button on the Horizontal Navigation Bar (see Horizontal Navigation Bar in 2 |
| Behaves as a toggle button and stops trend logging when you click |
.3 | Edit | Displays the trends workspace in the Edit mode. |
4 | Zoom mode | Displays the chart data in the zoom mode for the selected time interval. See Zooming Data in Trends Step-by-Step. |
5 |
| Displays the following options: |
6 | Pre-defined time ranges | Displays the trend series according to the selected time range. |
Trends Workspace – Edit Mode
The Edit mode allows you to modify the properties of the selected trend view definition, online or offline trend log object.
1 | Legend | Displays information on the objects present in the trend view definition. You can specify the type of information to be displayed by clicking the Layout Setting Depending on the selected Text Representation the following type of object information displays in the legend: |
2 |
| Behaves as a toggle button and stops trend logging when you select |
3 |
| Displays the following options: |
4 | Options | Allows you to modify properties, such as trend name or time period, for which you want the data to reflect in the chart, chart properties, and so on. See Options Properties for additional information. |
5 | Series | Allows you to add new data points and modify the look and feel of the chart. See Series Properties for additional information. |
6 | Save | Saves the selected trend view definition. If you add new data points to an online or offline trend log object, then a new trend view definition is created. |
7 |
| Provides options to save the trend view definition with a new name or discard the changes. |
Options Properties
Allows you to modify properties such as the trend name, the time period for which you want the data to reflect in the chart, chart properties, and so on.
1 | Trend name | Allows you to enter the name for a trend view definition, which is stored as a description. |
2 | Default time period | Allows you to specify the time range, for which the trend data should display in the Trend View. |
3 | SubChart [n] | Displays the sub chart added to the trend view definition. |
4 | Left Y-Axis | Allows you to specify the Max, Min range for the left y-axis, which is displayed in the Trend View. Auto scaling: Shows the scale of the y-axis, based on the trend series data. A minimum and maximum range must be defined if auto-scaling is disabled. |
5 | Right Y-Axis | Allows you to specify the Max, Min range for the right y-axis, which is displayed in the Trend View. Auto scaling: Shows the scale of the y-axis, based on the trend series data. A minimum and maximum range must be defined if auto-scaling is disabled. |
Series Properties
Allows you to modify properties, corresponding to the individual trend series of a trend view definition.
1 | Add datapoint | Displays the Select Data Point dialog box that allows you to add one or more data points. |
2 |
| Provides options to add and remove sub charts. |
3 | Style | Allows you to select the appropriate style properties like Color, Width, Dash Type, Marker, and Smoothing for each trend series. See Style Properties for more information. |
4 | Data Point | Displays the description of the data point. You can also enter a name for trend series in the text box below, which is stored as a description in the current language of the user. |
5 | Y-Axis | Indicates the y-axis where the data point is scaled (left or right). |
6 |
| Allows you to remove the trend series from the trend view definition only. |
7 |
| Displays the properties of either a trended object or a trendlog object in the contextual pane below the Properties tab, on the appropriate selection. If you reduce the size of the Series tab, the Delete option Select Property: Displays the Select Property dialog box that allows you to select the appropriate data point property. The changes are reflected immediately in the TVD on changing the property. The Select Property option displays only if the data point has more than one property. Move to: Allows you to move the data points within sub charts. You can move a binary or multistate point to another sub chart, only if the point is not present in the other chart. In case of analog points, you can only move analog points of the same unit to other charts. The unit of analog points in the source and destination sub charts has to be identical. For example, you can move an analog point with degree Celsius as the Unit from Sub Chart 1 to Sub Chart 2, only if Sub Chart 2 has analog points with degree Celsius as the unit and there are less than 5 sub points in Sub Chart 2. Information: Displays the object information such as description, name, alias, device associated with, path, and so on. The object information also displays, when you select the object in the System Browser and select the information icon |
in Properties.
Style Properties | |
Color |
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Width |
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Dash Type |
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Marker |
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Smoothing | ON/OFF |
