It is redundant to send the other four settings each time you run the VI. Interchangeable Virtual Instrument IVI drivers are an exciting new instrument control software technology. You should close references to all ActiveX sessions and interfaces when you are finished using them. This code will be useful only for that particular instrument-specific driver. The option string configures the IVI driver features that you choose:

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When you have a standard vii to instrument drivers, you can work more quickly because you do not need to learn a new interface for each new instrument. Replace the default logical name, NewLogicalName, with the new case-sensitive name of your choice, such as MyDmm.

Simulation is a very powerful, yet often misunderstood capability with regard to instrument drivers and instrument control in general. The class driver knows which specific instrument driver to call and what attributes to call when you configure a logical name in MAX and pass it to the class driver’s Initialize VI.

You should develop an application with IVI instrument drivers in the same way that you develop applications with traditional LabVIEW drivers, except that you can also take advantage of the new IVI features described in this. Dottable properties have a blue glyph next to the property name. To achieve interchangeability, the IVI Foundation has defined specifications for the following thirteen instrument classes: Even though no commands will be sent to the instrument and no actual data will be acquired, your test program will still go through all of the configuration functions required to set up the instrument.


Using a Simulation Driver with an Instrument-Specific Driver — The instrument-specific driver performs a very important role ensuring that the values to be sent to the instrument are within range for that particular instrument even when the instrument is not connected to the computer.

Or, when you are using an oscilloscope driver in simulation mode, the ReadWaveform function will return an array of random numbers within valid ranges for the scope. The internal differences between traditional drivers and IVI drivers should not affect your use of driver VIs to develop an application. Make sure the option string is empty when you use the MAX approach. The Type Library list contains the type libraries for all the registered ActiveX servers on the system in alphabetical order.

In effect, you can test a new instrument before you purchase it to make sure it will work in your system. The Simulation Driver, a generic library that performs more flexible data generation operations, is called only when measurement functions in the driver are called.

However, we believe that simulated data is very application specific. Selecting a dotted property. Therefore, you do not have to have the instrument connected to the computer ii perform range checking. However, as you can imagine, random data is not very meaningful for your program or your units under test UUTs. Standardization in IVI also enables instrument interchangeability in your test system.

This app note cannot be implimented because the version of MAX referenced is obsolete. This range-checking operation happens completely in software in the specific driver. This configuration enables the class drivers to use virtual channel names to make calls to a specific driver regardless of the specific driver’s channel name style.


Using IVI Drivers in LabVIEW

A class labvifw is a set of functions and attributes for controlling an instrument within a specified class, such as an oscilloscope, DMM, or function generator. Choose two IVI-C specific drivers to use in the examples.

Instrument driver calls — The simplest form of simulation is the ability to make calls to an instrument driver when the instrument is not connected to the computer. By providing high-level VIs for programming, they eliminate the need for application developers to learn complex programming protocols.

Getting Started Using National Instruments IVI with LabVIEW or LabWindows/CVI

To reduce any discrepancies, the driver coerces or rounds values to the actual value that the instrument uses internally. These two drivers must be from the same class. With a test system built on IVI technology, engineers can integrate the driver of a new instrument and run their programs against this driver in simulation mode. Whenever a discussion about simulating an instrument occurs, most users immediately think of simulating ovi data returned from an instrument.

What is IVI? – National Instruments

An error reported from status checking does not invalidate the cached state of the instrument. The developer can conditionally call the error query VI to learn more details about the instrument-specific error. This is the second level of simulation that you can use with IVI drivers. You can configure IVI drivers settings independently of a test application.

Back to Top 2. The IVI class specification: