Structure and Rules
All VTScada applications are built on other applications. At the lowest level is the VTScada library, which provides the development environment, tag and widget definitions, and all the user-interface elements that make up an application.
Script vs. Standard Applications
There are two basic types of VTScada application: Script and Standard.
Script applications are written in a text editor using the VTScada scripting language. Script applications are not based upon the VTScada Library Layer and therefore do not have access to the Display Manager, Idea Studio, built-in pages such as Reports and the HDV, the Alarm Notification System or any of the other tools and features provided in the VTScada Layer.
Look in the VTScada Application Manager for examples of script applications. Several useful script application utilities are included with every copy of the program. These include debugging and monitoring tools such as the Source Debugger, the VTScada Internet Monitor, etc.
Script applications are seldom used for SCADA purposes, now that you can create standard applications.
Standard applications are based on the VTScada Library layer. These inherit the features and functionality not available to script applications, including:
- The display manager. (Pretty much everything you see in an application.)
- Page navigation including menu, page change buttons & page history buttons.
- Tag browser and tag templates (Analog Status, Modem, etc).
- Alarm management.
- Menu item tags
- VTScada Idea Studio (configure pages and all the widgets and objects within your pages)
- Shapes, widgets and images.
- Alignment and spacing tools (align objects left, right, top or bottom. Space objects horizontally or vertically)
- Default Application Pages including...
- Alarm page (view different alarm categories, manage alarms and alarm sounds)
- Historical Data Viewer page (plot tag data on a graph)
- Reports page (generate a variety of report types in varying output formats from a selection of tag data)
- Operator Notes page (create and view time-stamped notes)
OEM applications. You can build new applications on top of any existing standard application. The new application will inherit all the features of the older one, exactly in the same way that a standard application inherits the features of the VTScada Library layer. This is useful in many situations and essential for anyone building a set of subordinate applications, all monitored by one master application.
Local vs. multi-server applications
A further distinction between VTScada application types is whether they are "local" or "multi-server". If local, the application runs on only a single workstation. If multi-server, the application is designed to run simultaneously on multiple servers and workstations, sharing data and tasks between them and automatically continuing without interruption should a server fail.
The application itself is the same whether local or multi-server. The difference is in the presence or absence of a server list.
