Choosing the Right Interface to Control Instruments in LabWindows™/CVI™

Publish Date: May 15, 2020 | 4 Ratings | 4.25 out of 5 | Print | Submit your review

Overview

This document guides you through choosing the right connectivity interface to control and communicate with your instrument in LabWindows/CVI.

National Instruments provides a wide array of instrument connectivity interfaces designed for different needs. Therefore, it is important to choose the proper one for your application. First, refer to the following flowchart to determine the correct method to control your instrument. Then, refer to the section corresponding to the flowchart number to learn more about the interface.

Table of Contents

  1. Use Plug and Play Instrument Driver
  2. Use IVI Instrument Driver
  3. Modify Existing Instrument Driver
  4. Create Instrument Driver
  5. Use NI-VISA API
  6. Use NI-488.2 API
  7. Use NI Device Driver
  8. Submit Instrument Driver Request
  9. Additional Resources

Connectivity Interfaces for Instrument Control

 

When getting started, National Instruments recommends using an instrument driver. Instrument drivers save you development time and cost because you do not need to learn the programming protocol for each instrument. The two types of instrument drivers are described further in this document.

 

1. Use Plug and Play Instrument Driver

A LabWindows/CVI Plug and Play instrument driver is a set of ANSI C software routines exported from a DLL. You can call these instrument drivers from any development environment that supports calls into DLLs.

 

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2. Use IVI Instrument Driver

IVI drivers are DLL-based drivers developed in LabWindows/CVI that allow for simulation and instrument interchangeability. To achieve interchangeability, the IVI Foundation defines specifications for the following instrument classes: DMM, oscilloscope, arbitrary waveform/function generator, DC power supply, switch, power meter, spectrum analyzer, and RF signal generator. IVI drivers also provide additional benefits like instrument state caching for improved performance, multithread safety, and instrument attribute access.

 

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3. Modify Existing Instrument Driver

If an instrument driver doesn’t exist for your instrument but a similar driver exists, you can modify the existing driver to fit your application needs.

 

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4. Create Instrument Driver

If an instrument driver doesn’t exist for your instrument and there aren’t any similar drivers, you can create an instrument driver from the Instrument Driver Project Wizard.

 

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5. Use NI-VISA API

NI-VISA is the National Instruments standard I/O API for instrumentation programming. NI-VISA can control GPIB, serial, USB, Ethernet, PXI, or VXI instruments, making the appropriate driver calls based on the instrument type so you do not have to learn instrument-specific communication protocol.

 

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6. Use NI-488.2 API

Use NI-4882 to develop and debug an application program for GPIB instruments. The NI-488.2 driver has high-level commands that automatically handle all bus management. Low-level commands are also available. LabWindows/CVI examples installed with the driver can be found in NI Example Finder.

 

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7. Use NI Device Driver

For NI modular instruments, use the device drivers provided by National Instruments found in NI Driver Downloads. LabWindows/CVI examples installed with the driver can be found in NI Example Finder.

 

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8. Submit Instrument Driver Request

If the Instrument Driver Network does not have the driver you need, you can submit an instrument driver request. These requests are monitored by the National Instruments Instrument Driver group and are developed based on popular demand.

 

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9. Additional Resources

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