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The module provides in OpenSCADA a mechanism of the final visualization of the visual control area (VCA). The module is based on WEB technologies (XHTML, JavaScript, CSS, AJAX). In its work, the module uses the data from the VCA engine — module VCAEngine.

Visual control area (VCA) is an integral part of the SCADA system. It applies to the client stations with a view to providing accessible information about the control object and to for the the issuance of the control actions to the object. In various practical situations and conditions the VCA, based on different principles of visualization, may by applied. For example, this may be the library of widgets Qt, GTK+, WxWidgets or hypertext mechanisms based on the technologies HTML, XHTML, XML, CSS and JavaScript, or third-party applications of visualization, realized in various programming languages Java, Python, etc. Any of these principles has its advantages and disadvantages, the combination of which could become an insurmountable obstacle to the use of VCA in a practical case. For example, technologies like the Qt library can create highly-productive VCA, which will undoubtedly important for the operator station for control the technological processes (TP). However, the need for installation of that client software in some cases may make using of it impossible. On the other hand, Web-technology does not require installation on client systems and is extremely multi-platform (it is enough to create a link to the Web-server at any Web-browser) that is most important for various engineering and administrative stations, but the productivity and reliability of such interfaces is lower, that actually eliminates the using of them at the operator stations of TP.

OpenSCADA has extremely flexible architecture that allows you to create external interfaces, including user, in any manner and taste. For example, the OpenSCADA configuration environment available now as by means of the Qt-library, and also the Web-based.

At the same time, independent creation of the VCA implementations in different basis may cause the inability to use the configuration of one VCA into another one. That is inconvenient and limited from the user side, as well as costly in terms of implementation and follow-up support.

In order to avoid these problems, as well as to create as soon as possible the full spectrum of different types of VCA, the generic concept of VCA is established. The result of this project — this direct visualization module (based on the Web-technologies), direct visualization module Vision and the VCA engine VCAEngine.