AnsweredAssumed Answered

VRF - Spectrum Analyzer hangup

Question asked by VRFuser on Jan 21, 1999
Hello Kurt,

     I too am using VEE with a spectrum analyzer HP859X series, and am
interested in your problem.  My application is measuring environmental & man
made noise levels.  In writing my code, I found that developing an interrupt
handler is VERY important.  At first I wasn't worried about Service requests
because my program didn't "need" to run faster than the analyzer could
perform measurements and return the data.  This wasn't efficient however,
because VEE would freeze while waiting for the analyzer, and I couldn't
always tell exactly what was happening on the bus.  Using SRQs allowed the
processor (your computer) to spend more cycles interacting with me while
waiting for analyzer data.

     Basically, I'm guessing that you've got a CPU / Analyzer state tracking
problem - that you're program may be getting ahead of the analyzer.  Be
warned though, that SRQs and trace initiation are very tricky.  Certain
analyzer commands automatically initiate sweeps or other bus activity even
though it may not be blatantly obvious.  I've developed and used my SRQ
routine to help me verify that the analyzer is always doing exactly what my
execution string thinks it is doing.  Best of luck.



-----Original Message-----
From: []
Sent:     Thursday, January 21, 1999 12:51 AM
Subject:     VRF - Spectrum Analyzer hangup

I am using VEE 5.01 with an HP8590A spectrum analyzer, a Matrix CATV
automatic signal generator and Matrix RF automatic filter bank. I am using
I/O to for all the instruments just to be consistent. I am trying to read
the level of a certain frequency from the generator using the spectrum
analyzer, then I send the generator code to increase or decrease the
carrier level. It may take 20 times to read and adjust the level.

My problem is after about 10-15 analyzer readings and level adjustments the
analyzer I/O command generates an error during the READ command. Using the
BUS I/O Monitor function in VEE I could see it start to read but then it
sends the previous WRITE command that I had used to get the marker level (
MKA? ).

Would using the panel driver for the analyzer help to solve this or is
there something with the READ terminator I need to focus on?   Do I need to
add some delay before making the reading? Is there something else I am
FYI: I am only using the 8590A to help me write the program. I will be
using an HP8591E when in actual use.

Thanks for the help.
Kurt Linn
Test Engineer
Thomas & Betts