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PXA Frequency Count resolution using SCPI

Question asked by Loquito on Aug 24, 2011
Latest reply on Aug 25, 2011 by MikeM
Hi y'all,

My issue: When I program the N9030A to do a frequency count measurement, it does it beautifully on the instrument's front panel, but the value I get back in my LabVIEW program is always rounded to kHz resolution. Example: Front panel reads 9 750 000 422.433 Hz, but my value in LabVIEW is 9 750 002 000.000. (I only get all the zeroes when I format my indicator to "%.3f" hoping it would give me all the way to the Hz resolution.) As a side note, it's odd that it rounded up to 2kHz, not 1kHz. How does 422 Hz go up to 2kHz?

How do I get the full frequency count measurement resolution through the GPIB to my program to match what I can see on the front panel? I think it's irrelevant that I'm using LabVIEW (as the Agilent driver is just a wrapper for SCPI commands). I just need help with figuring out the right SCPI commands to get the full resolution of the frequency count measurement.

What I've tried:
1) I'm using the example called "Agilent MXA Series Configure and Query Marker.vi" with a few mods necessary to run:
     -Deleted the Configure Sweep Coupling subVI as it would cause an error about reading before writing. Weird.
     -Added the Enable Marker Frequency Counter control to the Configure Marker Typ (Swept SA) subVI and set it to true.
     -Changed the Enable Continuous Sweep constant to true so I can see the frequency value when the remote measurement is done.
2) I went in to the different subVIs that configure different parts of the PXA and I changed the formatting commands to "%.3f" hoping that maybe I'm not getting the correct resolution out because the instrument isn't configured to return it that way. But really, in thinking about it the front panel displays correctly so it really should only deal with getting the value across the GPIB correctly.  

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