VBScript Reference Manual for InduSoft Web Studio

InduSoft Web Studio VBScript Reference Manual
About VBScript
Visual Basic Script Language (VBScript) is one of Microsoft’s scripting languages that is commonly
associated with Server-side and Client-side web applications. However, Microsoft has opened up
VBScript to developers and now VBScript can be found in a variety of applications. InduSoft has
standardized on VBScript since it provides a significant subset of Microsoft Visual Basic’s functionality,
and VBScript supports all of Microsoft’s operating system platforms including Windows CE, unlike VBA
(Visual Basic for Applications) which cannot support the Windows CE runtime environment.
VBScript is a programming language that is often viewed as a dialect of VBA (Visual Basic for
Applications), although it is really its own language. The VBScript language attempts to balance
flexibility, capability and ease of use. VBA is a subset of Visual Basic that was developed to automate
Microsoft Office applications, whereas VBScript was originally developed to support Server-side and
Client-side web applications. Although VBScript and VBA provide many of the same features, there are
some differences between them, primarily due to the applications they were each developed to support.
So before we get into details of the VBScripting language, perhaps it is worthwhile to review how
VBScript is used with InduSoft Web Studio (IWS) or alternatively, why VBScript is included with IWS.
IWS provides an easy-to-use development environment that configures predefined objects to support
an HMI/SCADA application. Applications can be built quickly and are relatively easy to support, even by
someone other than the original developer. By comparison, programming languages such as Visual
Basic can be used to develop an HMI/SCADA application, but the lower per-copy licensing cost savings
quickly gets offset by much higher development costs and support costs. A programming development
environment is clearly more flexible than a configuration development environment, but there is a
significant cost associated with programming that makes it an unattractive alternative for HMI/SCADA
applications. By adding VBScript support to IWS, InduSoft lets you chose between configuration and
programming to meet your application needs and develop applications efficiently.
Using VBScript With InduSoft HMI/SCADA Applications
InduSoft Web Studio (IWS) supports both a simple, proprietary scripting language (worksheet style) using one
or more Math worksheets, as well as VBScript (new with IWS Version 6.1). Developers can use either
scripting language or a combination of both. VBScript code is placed in one of several modules, based on the
functionality to be performed and the scope of the code and its variables. This subject is covered more
completely in the VBScript Configuration and Operation in IWS section.
Examples of how VBScript can be used:
• To execute a logic sequence or a routine when opening or closing a screen, or while the screen is open
• To execute a logic sequence in the background
• Run a simple VBScipt code segment based on an IWS object’s command dynamic
• Interaction with IWS Tags and control of IWS built-in functions
• Manipulation of ActiveX Controls and ActiveX Control event handler
• Simple file I/O (e.g. text files)
• Database interfaces (e.g. via ADO.NET), especially where use of SQL is required
• Interface to Windows Management Instrumentation (WMI) and Web Services (via WSDL)
• Interface to Microsoft Office applications (e.g. Excel, Access, Word) and Microsoft Office components
via OLE Automation
• Run on a Web Thin Client
Where you should use IWS instead of VBScript
• User Interface. IWS does not support Windows Scripting, which typically provides the User Interface for
VBScript via Forms.
• Device I/O (e.g. PLC communications). VBScript does not directly support serial or network
communications.
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