Need to take fast measurements with Agilent 53131A controlled by PCI GPIB and LabVIEW 7.1

[vyresince]

I'm a student doing research with a professor of mine.  I'm using an HP (Agilent) 53131A Universal Counter to count frequency data.  What we hope to do (provided that it is not impossible) is to take frequency data with a gate time of about 0.8 seconds.  However, when we used LabVIEW to control the counter there is a significant delay between each measurement.  In other words, the frequency measurements slowly drift (Whenever I set the gate time to 5 seconds and timed the measurements, the first measurement occured at 5 seconds, the next at 10 seconds, but then it starts to drift and they occured at 11s, 16s,21s,27s,32s,38s, and so on).  So my question is: is it possible to take this frequency data without this drift/delay between measurements?  If so, how can I do this using LabVIEW. 

What I have tried so far is to use LabVIEW's Instrument I/O Assistant, but this resulted in a significant delay between measurements.  I then downloaded drivers for the HP (Agilent) 53131A Counter and tried using the example code provided with those drivers to take the measurements and I was unable to even control the gate time very easily.  I also have the NI 488.2 drivers and the NI VISA drivers which I have not tried using.  Would either of these be faster?  Is what I'm trying to do possible?  Is it that remotely controlling the device simply results in too much delay for what I hope to do?  Due to my lack of experience, I just don't know the answers to these questions and hope that all of you experienced developers could assist me. Also, if it's possible I wouldn't mind setting my VI up to where it simply records the data from the HP Counter instead of trying to both initialize/configure the counter and record data.  Thank you in advance for any and all help.  I hope I've provided enough information and haven't asked too many questions. 

[nyc_(is_out_of_here)]

Have you downloaded the manual for this instrument from the Agilent website?

That is a very good place to start to understand the workings of this counter.

I would first try to operate the counter in manual mode and then use the LabVIEW.

The Agilent webpage for this instrument has an Application Note about how to make better frequency counter measurements.

Message Edited by nyc on 05-25-2006 01:41 PM

[vyresince]

I have a few manuals, but I think they are for a similar counter and not this exact counter.  Thanks for the advice, I'll download the exact manual and see if it yields any results.

[f.grasdepot@laposte.net]

Hi,

with the manual, you can experiment with the commands at url:
www.labtab.com/ni_gpib0, this gives you a direct gpib dialog with
output/enter on a gpib device at address 1 and an NI controller
declared as GPIB0 ... Making a driver is then easier...

FG

[MissyS]

Hi vyresince,

Which instrument driver did you download? The IVI driver or the Play and Play instrument driver? Here is a link to the download page for either of these drivers. The Plug and Play driver is using NI-488.2 function calls underneath. The instrument driver allows you to program the instrument without having to know the lower level ASCII (SCPI) commands that are required to set up the device (you'd need these if you were using NI-VISA or NI-488.2). However, you will need to know the terminology that the instrument uses to describe the different measurement methods. The manual should help with this. The programming guide can be found here, and the operating guide is here.

Which LabVIEW example are you using when you see the drift in measurements?

Regards,