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This demo shows an example of a generic SCADA Viewer application
deployed in a web browser as a Java applet that uses GLG Java class library. The
demo is an example of a SCADA viewer that loads arbitrary drawings
created by the end users and updates them with data without any
knowledge about the content of the drawings. As a result, no source
code changes are required to add a new drawing or to add more objects
into an existing drawing.
A configuration file is used to define a set of
drawings to be displayed. On start-up, the Viewer reads the configuration file and
initializes the navigation menu based on the information
provided in the configuration file. A new drawing can be added to the
Viewer by simply adding its filename to the configuration file.
The end users create drawings using either the
GLG Graphics Builder or GLG HMI Configurator and use data tags to
define the source of data for run time updates. The SCADA Viewer loads
the drawings, queries the list of tags defined in each drawing and
updates the tags from the datasources specified by the end user.
The demo uses a similar generic approach for
defining popup dialogs to implement drill-down functionality. All
information about the popup dialogs is defined in the drawing: a new
popup dialog may be added by editing the drawing and without any changes to the source code of the viewer.
The demo also demonstrates the use of an
integrated zooming and panning API. By default, it zooms and pans the
drawing displayed in its viewing area. However, when the Real-Time
Strip-Chart is activated by a corresponding button, the same code zooms and scrolls the data displayed in the
The demo uses simulated data.
However, provided with
a data source in a real application, it will display live data.
The demo demonstrates the following features of the GLG Toolkit: