*IND? is not working for Agilent E5272A on Measurements & Automation.

[Gaudier]

Other instruments work ok, I change  GPIB and same problem with the Agilent, the problem is that the computer is not reading this particular instrument for some reason that we don’t understand.

I guess I'll need to learn how to get my readings from VISA interactive control. If I do get measurements using the only thing that works (VISA int. control); how do I transport the data to an analyzing environment (LabVIEW, Matlab, Matematica,Exel, etc.)?

 

[Dennis_Knutson]

It sounds like you may need to send the instrument in for repair. The Instrument I/O Assistant works the same way as the VISA Interactive Control. You get an error there so I don't quite understand why the interactive control works. Just so I understand everything you are doing in the interactive control, you go to the Write tab and have the string '*IDN?\n' and then click the execute button. You then go to the Read tab, click the execute button and in the buffer window, see a string? You have to be able to do an execute in both tabs without an error. If that's the case, then the LabVIEW code below will do the exact same thing as the VISA Interactive Control. If the code below works, then try removing the \n character. A GPIB instrument is not supposed to need this and I'm curious whether you would get the error.

Message Edited by Dennis Knutson on 08-01-2007 10:03 AM

[Gaudier]

Here I show the VISA interactive control responding and LabVIEW not. It gives the same result with or without \n.

[Dennis_Knutson]

That's a completely different error code. That's timeout error. The results from the interactive control query are strange. Most GPIB instruments do not return a CR/LF. I'm wondering if the instrument requires a different termination character at the end of the command string. First, make sure that the string constant where you have the *IDN? is set for '\' Codes Display (right click on the constant). If it is, try putting a \r\n at the end of *IDN?

[Dennis_Knutson]

I just had a look at the instrument manual. I assumed that since this was a fairly new instrument, that it would use 488.2 termination. The 488.2 standard calls for terminating a command with just the GPIB EOI signal. It looks like it requires the CR/LF. That would explain a lot of the problems. The suggestion I made in the previous post should make the program work.

[Gaudier]

\r\n worked , thank you. Now I'll see if I can get a measurement reading into a VI.

[Dennis_Knutson]

You could try the Instrument I/O Assistant again. with the latest version, when you select the instrument, you have a Termination character entry. If you select 'Custom', you can enter  \r\n.

[Gaudier]

When I use custom termination character r\n\ on Instrument I/O Assistant, it automatically changes to r\, and when run a timeout error appears. Is it possible to convert a c++ program to LabVIEW with some kind of wizard? Because Agilent provides the codes I need in c language; I dont have any software to read this tipe of programing.

[Dennis_Knutson]

As I already mentioned, you can convert the driver from Agilent into LabVIEW VIs. If you have C++ code, you can create a dll from that and then use the Call Library Function Node. You can also use simple VISA Writes and Reads just like the example I posted with the *IDN? query.