Back to Blog
Ivi shared component6/7/2023 For more information on how to use the IVI Session Factory, see IVI-3.6: COM Session Factory Specification available on the IVI Foundation web site. The COM Session Factory is installed automatically by the IVI Shared Component installer. IVI-C drivers use a completely different mechanims (namely, IVI Class Drivers), to facilitate interchangeability. Note that, as the name implies, the COM Session Factory is only relevant for IVI-COM drivers. The COM Session Factory simply looks up the Logical Name in the IVI Configuration Store, locates the associated IVI-COM driver and instantiates it accordingly. For this to work, the user must create a Logical Name in the IVI Configuration Store and associate that Logical Name with the specific IVI-COM driver they with to instantiate. Rather than directly creating an IVI-COM driver using a CLSID (or the equivalent), the application program creates an instance of the session factory and then asks it to instantiate a specific IVI-COM driver. In spite of its simplicity, the session factory is a key to writing interchangeable applications that use IVI-COM drivers. The COM Session Factory (or, simply, the session factory)is a very simple COM component supplied with the IVI Shared Components. Specifically, if the user wishes to use a different instrument (and, hence, a different driver), then this CLSID (or class name in Visual Basic) must be manually changed and the program re-complied and re-linked. Yet, having a direct reference to such an instrument-specific item in an application program renders that application non-interchangeble. Irrespective of the IDE in use, this identifier must somehow be provided to instantiate the driver and begin calling methods and properties. In Visual Basic, this reference takes the form of a class data type, while in Visual C , a CLSID must be specified. IVI-COM drivers, like all COM components, must be created using a specific, hard-coded reference to the main COM class. For more information on how to use the IVI Configuration Server, see IVI-3.5: Configuration Server Specification available on the IVI Foundation web site. The IVI Configuration Server is installed automatically by the IVI Shared Component installer. Thus, the Foundation provides a COM component known as the IVI Configuration Server for programmatically reading and writing information to the Configuration Store. The Configuration Store is highly self-referential and easily corrupted if modified directly. The IVI Foundation discourages users and driver developers from directly manipulating the Configuration Store XML file (IviConfigurationStore.xml). End users can specify logical names for IVI drivers and virtual names for channels.įor more information on the structure of the IVI Configuration Store, see IVI-3.5: Configuration Server Specification available on the IVI Foundation web site. End users add information to the Configuration Store to describe how they intend to use IVI drivers in their system. IVI driver installers are required to populate the Configuration Store with information such as the instrument classes supported, the instrument models for which the driver is designed, and the physical channel names understood by the driver. This file is known as the IVI Configuration Store and serves as a central repository for IVI driver configuration information. When the IVI Shared Components are installed, a special XML file named IviConfigurationStore.xml is placed in the \Data directory. The IVI Shared Component installer is available for download from the IVI Foundation web site. The root of this directory structure is referred to as the IVI install directory () and is typically \IVI Foundation\IVI. The IVI Shared Component installer creates a directory structure to house the IVI Shared Components as well as IVI drivers themselves. Third parties are not allowed to develop custom installation programs for the IVI Shared Components. Moreover, the Foundation's Shared Component installer is the only IVI-compliant way to install the IVI Shared Components. The IVI Foundation provides an installer for the IVI Shared Components. The following sections provide a brief overview of some of the most important IVI Shared Components. In fact, IVI driver installation programs are required to check for the presence of the IVI Shared Components before installing. These components are collectively referred to as the IVI Shared Components, and they must be installed on any computer that will use IVI drivers. In order to facilitate IVI driver development and to ensure a consistent experience for end users building IVI-based test systems, the IVI Foundation develops and maintains a series of freely available software components.
0 Comments
Read More
Leave a Reply. |