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VISA (Virtual Instrument Software Architecture) is an API for communicating with test & measurement instruments.

JVisa is a library for using VISA instruments in a Java program.

JVisa has been tested on Windows 7, Windows 10, Windows 11, and macOS 10.15. I think it should work on Linux too.

A small number of VISA functions been implemented, but it's definitely enough to do instrument automation.

This project is a fork of Günter Fuchs'sproject of the same name, which is hosted on SourceForge.

Günter set upJNAerator andJava Native Access to interact with VISA DLLs. That was a significant step forward.

However, there were some issues in the original JVisa:

• Confusing inheritance between theJVisa andJVisaInstrument classes
• Only one instrument can be opened at a time
• C-style error handling and output arguments

This fork of JVisa addresses those issues.

You must install a VISA implementation to use JVisa.National Instrument NI-VISA is recommended.

As far as I know, four companies have written their own VISA implementation: Keysight, National Instruments, Rohde & Schwarz, and Tektronix.

The Nation Instruments implementation appears to be the most common. For instance,PyVISA only supports NI-VISA, and Rigol software uses NI-VISA.

I tried out all four implementations and took notes and screenshots. See mycomparison of VISA implementations.

You can use JitPack, visithttps://jitpack.io/#xyz.froud/JVisa/2.0.0 for details.

Example for Maven:

<repositories>    <repository>        <id>jitpack.io</id>        <url>https://jitpack.io</url>    </repository></repositories>...<dependency>    <groupId>xyz.froud</groupId>    <artifactId>JVisa</artifactId>    <version>2.0.0</version></dependency>

Jitpack also builds and hosts Javadoc:https://javadoc.jitpack.io/xyz/froud/JVisa/2.0.0/javadoc

To manually download JVisa jar files, go tohttps://github.com/pfroud/JVisa/releases.

JVisa depends on theJava Native Access (JNA) library.

If you want a single jar file containing both JVisa and JNA, useJVisa-[version]-with-dependencies.jar.

If you already have a JNA jar file, you can useJVisa-[version].jar.

To download JNA jar files, I recommendhttps://mvnrepository.com/artifact/net.java.dev.jna/jna. First, click the version number of the newest version. Then, find the table row labeled "Files" and click on "jar".

Start by creating a Resource Manager:

JVisaResourceManagerrm =newJVisaResourceManager();

You can search for available instruments, or you can directly open an instrument if you already know its resource name:

String[]resourcesNames =rm.findResources();JVisaInstrumentinstrument =rm.openInstrument("USB0::0xFFFF::0x1234::123456789123456789::INSTR");

Examples of how to interact with the instrument:

StringmanufacturerName =instrument.getManufacturerName();StringmodelName =instrument.getModelName();instrument.write("source:voltage 12V");instrument.write("output on");Stringresponse =instrument.queryString("measure:current?");

When finished:

instrument.close();rm.close();

Thejvisa_example folder contains a few example files:

• The fileFindResourcesExample.java is a ready-to-run example of theResourceManager#findResources() method.
• The fileIdentificationQueryExample.java shows how to open instruments and send a query.

There is also a small example of how to make a higher-level abstraction. The fileAbstractionExample.java shows howAbstractInstrument.java andPowerSupplyExample.java let you call a method likesetVoltage(12) instead ofwrite("source:voltage 12V").

It is possible to run the examples directly from the jar file.

If you have a JVisa jar file which contains the JNA dependency:

java -classpath"C:\path\to\JVisa-[version]-with-dependencies.jar" xyz.froud.jvisa_example.FindResourcesExample

Otherwise, specify a path to a JNA jar file, separated with a semicolon:

java -classpath"C:\path\to\JVisa-[version].jar;C:\path\to\jna-[version].jar" xyz.froud.jvisa_example.FindResourcesExample

For documentation about thejava command, seehttps://docs.oracle.com/javase/8/docs/technotes/tools/windows/java.html.

Here are some initialisms you might encounter when learning about test & measurement software.

• USBTMC: USB Test & Measurement Class.

• IVI:Interchangeable Virtual Instruments and the Foundation with the same name. TheirShared Components library

• IEEE-488 aka GPIB:General Purpose Interface Bus. Specifies a physical connector and the signals used.

• SCPI :Standard Commands for Programmable Instruments. Gives us command syntax likemeasure:volrage:dc?.

• LXI:LAN eXtensions for Instrumentation. Communicate with test & measurement instruments over Ethernet.

• PXI:PCI eXtensions for Instrumentation. Communicate with test & measurement instruments over PCI. Based onCompactPCI, which is different from PCI on desktop motherboards.

• VXI:VME eXtensions for Instrumentation. Communicate with test & measurement instruments over theVMEbus.

• ASRLstands for asynchronous serial. When using NI-VISA on Windows, the VISA resource name to comunicate through a serial port starts with "ASRL" instead of "COM". But watch out because the ASRL number may be different from the COM number!