Open a labview window to display GPIB data.

[ninskaya]

Hi, I would like to open a labview window an be able to see data in real time from an oscilloscope through GPIB. How can I do that? Thanks.
Ninskaya

[BJD1613]

If you are using the visa functions to communicate with your GPIB device you can display the output string in a loop from the VISA read function. So open the connection to the gpib device before you loop inside the loop do a visa read and outside the loop close the connection. Hope this helps.

[Dennis_Knutson]

You don't mention the type of scope or whether you're using a driver but I'm going to assume that you are. Every driver that I've seen has a function to return the scope waveform. It may be as a 1D array or as a waveform datatype. In general, all you have to do is wire a graph to the returned data. Most drivers come with an example that do this already. Put this in a loop and you'll have continously updating data. There is no such thing as "real time". The max data transfer rate for GPIB is 1MB/sec and real world numbers are usually much less. From the number of samples you request from the scope, you should be able to determine the delay between the scope acquisition and the display on your computer.

If you need more details, please provide the make and
model of the scope that you're using.

[ninskaya]

Hi BJD1613, thanks a lot for your answer. Do you know how I can find my GPIB address?

Ninskaya

[ninskaya]

Hi Dennis Knutson, thanks a lot for your help. I am using ScopeExplorer as a scope. I am sorry, I don't really understand in which form the data will be. Shall I use the Read Visa vi like another person suggested and if yes how can I found out about the GPIB address?

Thanks,
Ninskaya

[ninskaya]

Sorry, the scope is a Lecroy Scope Explorer version 2.12.

Ninskaya

[BJD1613]

You will be able to open up Measurment and Automation Explorer (MAX) to view all devices configured on your machine. You should be able to see what address it is under gpib devices.

[ninskaya]

Thanks a lot.

Ninskaya

[Dennis_Knutson]

ScopeExplorer is not a scope. It is a program that communicates with LeCroy scopes. Go to LeCroy's web site for LabVIEW Drivers or NI's Instrument Driver Network for LeCroy and download the driver for your brand of hardware. If you have a choice, get a LabVIEW driver as opposed to an IVI driver. An IVI driver will work but it's a bit harder to setup and you won't be able to modify the program or even see the code unless you also have LabWindows/CVI. In either case, with the dri
ver you won't have to do any VISA Reads yourself unless you feel like you want to recreate what has already been done for you. The Instrument Driver Network main page has some links to definitions of the different types of instrument drivers and how they should be used.

Message Edited by Molly K on 02-18-2005 11:57 PM

[ninskaya]

Hi Dennis, thanks a lot. Actually, I have already downloaded the driver (saved the mnu files and llb libraries) but then I still have to use a vi which asks me for a VISA connection. The attached vi which I am using gives me an "old VISA open" error message.

Thanks,
Ninskaya