Readme

Description

This is a minimalistic wrapper around NI-VISA's 64 bit dll.

National Instrument's current C# solution is only available for .NET Framework 4.8.

This project is written in .NET 6.0 but can be compiled for whatever version you are using.

Special Thanks

I used the Rohde-Schwarz Visa implementation as a guide for creating this small project. Their Nuget Package "RsInstruments" is a very powerfull implementation of Visa and freely available under the MIT license.

Unfortunately, I needed something closer to the metal that could be adapted to work with older equipement.

Prerequisites

Install NI-VISA.

This will place the visa64.dll on your computer. This code references that dll.

Example

See TestingNetVisa\Program.cs

using NetVisa;

namespace MyApp;

public class Program
{
    static void Main(string[] args)
    {
        // Create a resource manager.
        // This creates a singleton that will close when the app terminates.
        var rm = Resource_Manager.Get;

        // Read all the resources connected to this PC
        var resources = rm.FindResources();

        // Show them on the console
        Console.WriteLine(string.Join('\n', resources));

        // Create a connection to a power supply
        using var visa = new Visa_Session("GPIB0::29::INSTR", rm);

        // Set the timeout
        visa.Timeout = 5000;

        // Write
        visa.Write("VSET 5");

        // Read
        var vset = visa.ReadString();

        // Prints: "VSET 0.000   \r\n"
        Console.WriteLine('"' + vset.Replace("\n", @"\n").Replace("\r", @"\r") + '"' + "\n");
    }
}

Disclaimer

I am not responsible for this code. I make no guarantees. This is really meant as a starting point for others to continue the project if they are interested.

This works with GPIB. In theory, this also works for Ethernet (Sockets), Serial (USB), VXI11, and LXI instruments. But I haven't tried it.

Helpful References:

https://www.ni.com/docs/en-US/bundle/labview/page/lvinstio/visa_find_resource.html

https://www.ni.com/docs/en-US/bundle/ni-visa/page/ni-visa/vireadstb.html

https://pyvisa.readthedocs.io/en/1.8/shell.html

https://forums.ni.com/t5/Measurement-Studio-for-NET/Ni-DAQmx-NET6-Support/m-p/4272106#M21908

https://www.ni.com/docs/en-US/bundle/ni-daqmx-c-api-ref/page/cdaqmx/help_file_title.html

https://www.ni.com/docs/en-US/bundle/ni-visa/page/ni-visa/description_of_the_api.html

C:\Program Files\IVI Foundation\VISA\Win64\Include\

https://documentation.help/VISA.NET/VISA%20Attributes%20Table.htm

Definitions

SRQ => Visa Service Request

This is used for the instrument to communicate back to the controller at a time when the controller is not planning to talk with the device. https://documentation.help/NI-VISA/StatusServiceRequestService.html

OPC => Operation Complete

You can send multiple commands to an instrument and they will be queued by the instrument. However, before querying the instrument it is best to make sure the "Operation Completed" using the "*OPC?" command. https://www.keysight.com/us/en/lib/resources/training-materials/using-opc.html

jrdnwrth/NetVisa