VBScript Reference Manual for InduSoft Web Studio - ICP DAS

InduSoft Web StudioVBScript Reference ManualAbout VBScriptVisual Basic Script Language (VBScript) is one of Microsoft’s scripting languages that is commonlyassociated with Server-side and Client-side web applications. However, Microsoft has opened upVBScript to developers and now VBScript can be found in a variety of applications. InduSoft hasstandardized 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 forApplications), although it is really its own language. The VBScript language attempts to balanceflexibility, capability and ease of use. VBA is a subset of Visual Basic that was developed to automateMicrosoft Office applications, whereas VBScript was originally developed to support Server-side andClient-side web applications. Although VBScript and VBA provide many of the same features, there aresome 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 howVBScript 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 supportan HMI/SCADA application. Applications can be built quickly and are relatively easy to support, even bysomeone other than the original developer. By comparison, programming languages such as VisualBasic can be used to develop an HMI/SCADA application, but the lower per-copy licensing cost savingsquickly gets offset by much higher development costs and support costs. A programming developmentenvironment is clearly more flexible than a configuration development environment, but there is asignificant cost associated with programming that makes it an unattractive alternative for HMI/SCADAapplications. By adding VBScript support to IWS, InduSoft lets you chose between configuration andprogramming to meet your application needs and develop applications efficiently.Using VBScript With InduSoft HMI/SCADA ApplicationsInduSoft Web Studio (IWS) supports both a simple, proprietary scripting language (worksheet style) using oneor more Math worksheets, as well as VBScript (new with IWS Version 6.1). Developers can use eitherscripting language or a combination of both. VBScript code is placed in one of several modules, based on thefunctionality to be performed and the scope of the code and its variables. This subject is covered morecompletely 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 componentsvia OLE Automation• Run on a Web Thin ClientWhere you should use IWS instead of VBScript• User Interface. IWS does not support Windows Scripting, which typically provides the User Interface forVBScript via Forms.• Device I/O (e.g. PLC communications). VBScript does not directly support serial or networkcommunications.InduSoft, Ltd. 5