I have a Agilent 8163 meter that communicates fine using GPIB most of the time with my Labview 6.0.2 program.

[Davorino]

This meter can work for several weeks taking thousands of readings and then it will crash. The error that the meter shows when it crashs is "switch2range called while already running". I have talked with Agilent about it and they cant duplicate the problem because they dont have the same equipment that I am using in this test system. NI wont help me much because this isnt thier product, of which I can understand. Is it possible for the Labview 488 VIs to be interrupted by another part of the program? Should I raise the priority of the VI that runs the 488 vi higher than the rest of the program?

[Dennis_Knutson]

I don't think the 488 routines are getting interrupted. From the error message, it seems you are sending a command to the instrument before it is ready to accept it. I'm not familar with the instrument so I don't know what the 'switch2range' command does but it would seem that sometimes it takes longer to execute. Is there a status bit that you can query to see when the command finishes? That way, whenever you execute the command, you don't proceed until the status bit says it's okay. You might also want to add some code to give you an indication whenever the time to execute it exceeds a certain amount of time. You could then use this to try to isolate the condition that causes the instrument to behave differently.