如何使用c#通过USB连接仪器

Question

我正在尝试使用 Ivi.Visa.Interop .dll 通过 USB 与 Voltech PM1000+ 功率计进行通信。我对 C# 比较陌生，不知道从哪里开始。我正在使用 Visual Studio 2015 社区。我已经与使用 GPIB 的不同工具进行了交谈，这里是代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Ivi.Visa.Interop;


namespace commOverIP
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void InitiateIOBtn_Click(object sender, EventArgs e)
    {
        ///testing out excel
        InitiateIOBtn.Text = "Initializing";



        try
        {
            // resource manager and message-based session manager
            Ivi.Visa.Interop.ResourceManager mngr = new Ivi.Visa.Interop.ResourceManager();

            // GPIB address
            string srcAddress = "GPIB::27::INSTR"; // GPIB address of data acquisition
            //setting up communication
            Ivi.Visa.Interop.FormattedIO488 instrument = new Ivi.Visa.Interop.FormattedIO488();
            Ivi.Visa.Interop.IMessage Imsg = (mngr.Open(srcAddress, Ivi.Visa.Interop.AccessMode.NO_LOCK, 1000, "") as IMessage);
            instrument.IO = Imsg;

            instrument.IO.Clear();//clear io buffer
            instrument.WriteString("*RST", true);//send RST? command to instrument
            instrument.WriteString("*IDN?", true);//send IDN? command to instrument
            returnOfCommand.Text = instrument.ReadString();//read IDN? result

            //close communication
            instrument.IO.Close();
            System.Runtime.InteropServices.Marshal.ReleaseComObject(instrument);
            System.Runtime.InteropServices.Marshal.ReleaseComObject(mngr);

            InitiateIOBtn.Text = "Initialize I/O";
            //*/
        }
        catch(Exception exp)
        {
            MessageBox.Show(exp.Message);
        }
        InitiateIOBtn.Text = "Initialize I/O";
    }
}
}

这工作正常，但 USB 似乎是一个不同的野兽。我发现的唯一真正的线索是在 .dll 中： IUsb.Init（字符串，Ivi.Visa.Interop.AccessMode，int，字符串） 我尝试实现这一点，但我真的不知道从哪里开始。

谁能给我一个如何查询“*IDN”的示例？命令会很棒。或者，即使有比通过 Ivi.Visa.Interop dll 更好的方法。

提前致谢

Answer 1

重新启动您的设备一次。清除 IO 也有帮助。之后以下代码应该可以正常工作：

    string resourceString= "USB0::xxx::xxx::xxx::0::INSTR";  
    ResourceManager manager = new ResourceManager();  
    FormattedIO488 connection = new FormattedIO488();
    connection.IO = (IMessage)manager.Open(resourceString, AccessMode.NO_LOCK, 0, "");
    connection.IO.Clear();
    connection.WriteString("*IDN?", true);
    string result = connection.ReadString();

Answer 2

我一直按照您的要求做，我完全理解这有多么令人沮丧。我记得做谷歌搜索想出这段代码。该代码实际上来自我购买 Agilent 82357B USB/GPIB 控制器时的一些是德科技文档。

这可以适用于任何 GPIB 乐器，唯一的区别是您发送到乐器的字符串。这些可以通过获取您感兴趣的仪器的编程手册来获得。

我安装了用于 Agilent 82357B 的 Keysight（以前称为 Agilent）I/O 库套件。不明显的一件事是您应该禁用“自动发现”选项，因为此功能有时会将您的设备置于本地模式。

using System.Threading;
using System.Runtime.InteropServices;
// Add reference for VISA-COM 5.9 Type Library
using Ivi.Visa.Interop;

namespace USBCommunications
{
    class Program
    {
        static void Main(string[] args)
        {
            Gpib.Write(address: 5, command: "*IDN?");
            bool success = Gpib.Read(address: 5, valueRead: out string valueRead);
            System.Console.WriteLine($"The ID is {valueRead}");

            System.Console.ReadLine();
        }
    }

    public class Gpib
    {
        static ResourceManager resourceManager;
        static FormattedIO488 ioObject;

        public static bool Write(byte address, string command)
        {
            resourceManager = new ResourceManager();
            ioObject = new FormattedIO488();

            string addr = $"GPIB::{address.ToString()}::INSTR";

            try
            {
                ioObject.IO = (IMessage)resourceManager.Open(addr, AccessMode.NO_LOCK, 0, "");
                Thread.Sleep(20);
                ioObject.WriteString(data: command, flushAndEND: true);

                return true;
            }
            catch
            {
                return false;
            }
            finally
            {
                try { ioObject.IO.Close(); }
                catch { }
                try { Marshal.ReleaseComObject(ioObject); }
                catch { }
                try { Marshal.ReleaseComObject(resourceManager); }
                catch { }
            }
        }


        public static bool Read(byte address, out string valueRead)
        {
            resourceManager = new ResourceManager();
            ioObject = new FormattedIO488();

            string addr = $"GPIB::{address.ToString()}::INSTR";

            try
            {
                ioObject.IO = (IMessage)resourceManager.Open(addr, AccessMode.NO_LOCK, 0, "");
                Thread.Sleep(20);
                valueRead = ioObject.ReadString();

                return true;
            }
            catch
            {
                valueRead = "";
                return false;
            }
            finally
            {
                try { ioObject.IO.Close(); }
                catch { }
                try { Marshal.ReleaseComObject(ioObject); }
                catch { }
                try { Marshal.ReleaseComObject(resourceManager); }
                catch { }
            }
        }
    }
}

编程愉快！！