This tutorial shows you how to find, install, and use an interchangeable virtual instrument (IVI-C) driver in LabVIEW or LabWindows/CVI. For more information about IVI drivers, refer to the IVI Foundation or the NI resources below.
Install the latest compatible version of the NI-VISA driver and IVI Compliance Package. Check the Readme for system and software compatibility or refer to the following for compatibility information.
Use the NI Instrument Driver Network to find and install the instrument driver.
For the purpose of demonstrating instrument interchangeability later in this tutorial, find and install two IVI-C specific drivers that are from the same class. The IVI class is indicated by the IVI Class Specification and Version on the instrument driver page. This tutorial uses the HP 34401A and Fluke fl45 DMM instrument drivers as examples.
Complete the following steps to configure your IVI system in NI Measurement and Automation Explorer (MAX).
Logical names allow you to define and name multiple driver sessions. You can switch between driver sessions by passing a logical name to the initialize function of a class driver, which identifies the software module and hardware asset to use. Application programs written using a class driver use logical names to avoid direct references to software modules and hardware assets.
A driver session defines a set of properties for use by IVI drivers, such as initial settings for attributes, virtual name mappings, simulation settings, and more.
Note: If you choose to simulate with a specific driver, the specific driver functions return random simulated values for output parameters that represent instrument data. If you choose to simulate with a class simulation driver, select the simulation driver that matches the class of your specific driver. The simulation driver extends the simulation capabilities built into all specific drivers and allows you to configure the nature of the simulated instrument data interactively. The simulation drivers appear in this list only if they are installed with the IVI Compliance Package.
Note: If the driver does not define configurable initial settings, these lists will be empty.
After configuring the IVI driver, you are ready to run an example. The instrument driver will install examples and the API required to communicate with your instrument. Use these examples as programming references and an easy way to start using your instrument.
Note: If you receive an error message after you change the configuration, the configuration settings may not match those of the instrument.
To view the IVI class driver calls made in this example, select File>>Open>>Source (*.c) to open the source code of the example.
To interchange instruments, update the driver session in NI MAX.
Note: You must install the IVI-C specific driver to see its driver session in the drop-down list.
If you are unable to find an instrument driver using the Instrument Driver Network, contact the manufacturer of your instrument directly. In some cases, instrument manufacturers make drivers available on their websites.
If using an IVI driver doesn’t fit your application needs, or you want to modify or create your own instrument driver, refer to Choosing the Right Interface to Control Instruments in LabWindows/CVI for more options.
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