Chapter 6
Historical Data Logging and Extraction
©
National Instruments Corporation
6-13
How Do You Change the Plot Colors
and Style in the Trend?
Click on the Trend Legend. The pop-up window contains several options
with which you can change the plot colors and styles used in the trend.
How Do You Zoom In on the Trend?
The HTV Trend palette contains a Zoom tool that allows you to zoom in
on points of interest. The Zoom tool has five modes with which you can
zoom in on the trend:
•
Zoom by rectangle
•
Zoom time scale
•
Zoom Y scale
•
Zoom in about one point
•
Zoom out about one point
Undo Zoom resets the graph to its previous setting.
How Do You Export Data to a Spreadsheet?
From the HTV, select File»Export…. The HTV exports the information
currently displayed in the trend to a tab-delimited file. A dialog box
prompts you for the name and location of the file to create.
The HTV resamples data in periodic intervals so that all tags have the same
number of data points. The frequency defaults to a value according to the
frequency of data in the historical files. If you want to override this value,
enter the frequency you want in the dialog box.
How Do You Get Online Help for the HTV?
From the HTV, pull down the Help menu and select Show Help. A floating
window is displayed that shows help information for all of the objects on
the HTV panel.
How Do You Set Tag, Time, and Color Preferences?
Set the preference for the HTV to remember settings for display time and
color on exit by selecting Viewer»Preferences…. When you exit the HTV,
the state of the viewer is recorded.