AnsweredAssumed Answered

Getting COMException errors after program was working (no changes done)

Question asked by meta on Nov 23, 2015
Latest reply on Nov 24, 2015 by meta

Like • Show 0 Likes0
Comment • 2

Hi, I used an example program for C# for GPIB interfacing. It was working fine with my equipment for more than a month but after today the program throws a COMException error with no code. The example program is:

namespace ExampleProgram
{
    class Program
    {

        public static int Main()
        {
                ResourceManager rMgr = new ResourceManagerClass();
                FormattedIO488 src = new FormattedIO488Class();

                string srcAddress = "GPIB0::30";

                *src.IO = (IMessage)rMgr.Open(srcAddress, AccessMode.NO_LOCK, 2000, null);*
                src.IO.Timeout = 2000;

                src.WriteString("*IDN?", true);
                string temp = src.ReadString();
                System.Console.WriteLine(temp);

            return 0;

        }
    }
}

The error is thrown where the bold line is. Basically, it means I cannot connect to my instruments from C#.

I am using the Visa COM library type 5.5 and netframework 4.6.

I really have no idea what could be wrong since Friday night (20-11) it was working fine but this morning (23-11) it did not work anymore and I did not change a single line of code. I noticed there was an IO library suite update on 21-11 but I do not know if this could be a factor.

I tried reinstalling my NI 488.2 drivers (i use a NI GPIB usb plug) and the IO library suite drivers but no good results.

Keysight Connection Expert still works properly. I can send GPIB commands to my instrument such as *IDN and I can read the correct response.

Any insight would be appreciated, thanks.

No one else has this question

Outcomes

inf_persistence Nov 24, 2015 5:35 AM

Perhaps the GPIB address was accidentally changed in the instrument? Is it still 30? I know that you mentioned Connection Expert still works, but perhaps CE auto-adjusted the address with its automatic scanning.

When you say "reinstalled IO Libraries", do you mean re-install with an older version to verify that the new version is giving problems?

What instrument are you connection to, by the way?

Actions

meta @ inf_persistence on Nov 24, 2015 3:35 PM

Yes, I checked to see if there were address changes but there weren't. Also CE also displays the same addresses as the one in my program. I have literally tried everything that came to my mind, I even took a clean computer and installed all necessary software and drivers (even VS C# from scratch). It gave me the same error when using Keysight's COM objects. I tried different oscilloscopes + PSU's and also no good results. In the end I just gave up on using Keysight's I/O library suite and just used an alternative and it worked easily from the first try, no complications whatsoever with my devices. I am really starting to doubt the problem is on my end, maybe an autoupdate broke my program but it is hard for me to be 100% sure.

To answer your questions, i reinstalled the I/O library suit twice. Once using the latest update and the second time using an update from August 2015. None worked.
I am connecting to a Lecroy oscilloscope and a Chroma power supply (both with GPIB support obviously).

Actions

2 Replies

inf_persistence Nov 24, 2015 5:35 AM
Mark Correct
Correct Answer
Perhaps the GPIB address was accidentally changed in the instrument? Is it still 30? I know that you mentioned Connection Expert still works, but perhaps CE auto-adjusted the address with its automatic scanning.

When you say "reinstalled IO Libraries", do you mean re-install with an older version to verify that the new version is giving problems?

What instrument are you connection to, by the way?
Like • Show 0 Likes0
Actions
- meta @ inf_persistence on Nov 24, 2015 3:35 PM
  Mark Correct
  Correct Answer
  Yes, I checked to see if there were address changes but there weren't. Also CE also displays the same addresses as the one in my program. I have literally tried everything that came to my mind, I even took a clean computer and installed all necessary software and drivers (even VS C# from scratch). It gave me the same error when using Keysight's COM objects. I tried different oscilloscopes + PSU's and also no good results. In the end I just gave up on using Keysight's I/O library suite and just used an alternative and it worked easily from the first try, no complications whatsoever with my devices. I am really starting to doubt the problem is on my end, maybe an autoupdate broke my program but it is hard for me to be 100% sure.
  
  To answer your questions, i reinstalled the I/O library suit twice. Once using the latest update and the second time using an update from August 2015. None worked.
  I am connecting to a Lecroy oscilloscope and a Chroma power supply (both with GPIB support obviously).
  Like • Show 0 Likes0
  Actions

Getting COMException errors after program was working (no changes done)

Outcomes

Related Content

Recommended Content