8.3. Diagram

8.3.1. General properties
8.3.2. Display
8.3.3. Scaling
8.3.4. Filter

The diagram element is used to display measurement data in graph form after generating a report, and contains other functions for evaluating and analyzing the data.

Figure 8.7. Diagram with harmonics

Diagram with harmonics

The automatically selects the display mode for the data based on the data type (spectrum, time recording, trend).

The preview shows a demonstration curve and not the actual data.

8.3.1. General properties

Open the Properties dialog box by pressing the left mouse button within the diagram area and select Properties from the context menu.

Figure 8.8. Diagram properties

Diagram properties

The most important property of the diagram is the selection of the data sources. The selected data sources are assigned to the left y axis by default; data sources can also be assigned to the right y axis, however. In the diagram an xy-view is possible. A trend data source can then be selected. The selected data source is used as an x axis in the diagram. Instructions on selecting the data source are given in the section on "Selecting a data source".

If the "Use default settings" box is checked, the view, scaling and time filter settings from the previous display settings of the template are used.

8.3.2. Display

In the report the filtered measurement data from the database are displayed in the diagram in the form of a curve. Depending on the diagram type – spectrum, time recording, trend, cascade, etc. – different evaluation and display functions are available:

You enlarge (zoom into) the diagram section by right-clicking an arbitrary position (usually the upper left corner), keeping the mouse button pressed and dragging the cursor in the desired direction (usually to the lower right); releasing the mouse button then sets the size of the zoomed area. As soon as you begin dragging, a frame with the current size of the section is displayed, which immediately adjusts itself to the new size with each movement of the mouse. After you release the mouse button, the diagram is redrawn and scaled with the zoomed section.

You can undo the enlargement in stages by quickly pressing ( less than 1 seconds) the left mouse button. You can display the diagram in its entirety again using the context menu (slow click, greater than 1 second, with the left mouse button) and selecting "Reset zoom".

The context menu contains the following other display functions:

  • Main cursor: show/hide the cursor

  • Delta cursor: show/hide a second cursor for determining the time between two points in time signals

  • Select channels: show/hide curves in the diagram

  • Autom. scaling: if the axes were manually scaled, this button allows you to scale automatically and redraw the curve

  • Reset zoom: gradually undoes the zoom section

  • Analyze diagram: the diagram is extracted to an extra window, which can be enlarged to full screen size and there analyzed in more detail. The settings entered are then applied to the original diagram when the window is closed.

The control box can be displayed by clicking the "i" at the top right of the diagram

Figure 8.9. Control box

Control box

By clicking the respective tabs you can change between "Control", "Display" and "Frequency Markers". In the "Control" tab you can switch on the "Main Cursor" irrespective of the diagram type, change between the "long" and "short" cursor displays, with multiple curves change the active cursor to another data channel and change between the Main and Delta Cursors. If a time signal is displayed in the diagram, you can also show or hide the Delta Cursor, in order to calculate the time and frequency between two points in the "Display" tab.

Double-clicking with the right mouse button positions the cursor at the next data point on the active curve. You can also move the cursor to the next data point with the right and left arrow keys. Additionally pressing the CTRL key with the arrow key makes the cursor jump along the data curve in larger steps.

Spectra allow you to execute the following analysis functions in the diagram and display the results:

  • Harmonics

  • Subharmonics

  • Side bands

  • Max. peaks

Here is an example of displaying four subharmonics:

Figure 8.10. Subharmonics

Subharmonics

The Main Cursor serves as the middle frequency in the harmonics and subharmonics. The Delta Cursor must be used for the side bands and maximum peaks. To change the middle frequency or the band spacing, you can move the cursor left or right to the next data point using the arrow keys; moving the cursor also immediately refreshes the display of the analyzed points. For all analytic functions, a numerical field is also offered to the right of the text for changing the number of calculation points. The analyzed diagram can be printed with the current analysis display or saved in the unchanged PDF report. Saving as a normal report loses the analysis data.

Note:

At the upper left in the diagram appears a small dot when the diagram is in focus. If you change to another input box or even to another application, the focus passes to the latter. You can retrieve the focus by clicking once inside the diagram area. The cursor can only be moved when the diagram is in focus!

8.3.3. Scaling

Scaling allows you to circumscribe the diagram with predefined ranges, to obtain comparable diagrams.

Figure 8.11. Scaling

Scaling

The option "Use OMNITREND default" is activated by default, with the effect that the settings from OMNITREND are used for scaling diagrams. If the settings for OMNITREND Web are to be individually adapted, this setting must be deactivated.

The settings for the individual axes can then be adapted; change between the axes by selecting the corresponding tab.

The example in the bottom picture shows the setting options for the left y axis. You can select between logarithmic or linear scaling.

The actual scaling of the display generally occurs automatically. If the display area is to be adapted by the setting, the option "Auto" must be deactivated and the value range as well as the axis division adapted.

The settings for the other axes are made analogously to this one.

Figure 8.12. Axis scaling

Axis scaling

Note: In the value range both positive and negative values can be entered, but keep in mind that decimals must be indicated by decimal points (e.g. -10.5) and not by commas as in non-English languages.

You can access Scaling via "Diagram properties". The scaling you set is permanently saved with the template. You can also enter these settings for each new template as default settings; see: Global display settings

8.3.4. Filter

The filter settings were already described in the section on "Settings".