Problem reading data from hp8559a spectrum analyzer via GPIB more than one time

[AlfK]

Hi,

I have a hp8559A spectrum analyzer main frame (with a hp853a spectrum analyzer) that has a broken display, but the rest is working fine. To get the data out of the spectrum analyzer I connected it via GPIB to my computer and wrote a small vi (see the attached file). I can successfully read the data from the spectrum analyzer, but only one time. After that, the data on the GPIB line is not updated, i.e. if I change the input signal at the spectrum analyzer, this new signal cannot be read-out via GPIB. I have to switch it off and on to get the new signal.

What am I doing wrong, any help or comment is appreciated...

[RamonaL]

Hi AlfK,

have you tried the VISA-Vis? You can find an example in the Example-finder if you search vor GPIB.

Please try this,

RMathews

[nyc_(is_out_of_here)]

The HP8559A spectrum analyzer is so old I can't find a programmer's manual for it.

[AlfK]

Hi RMathews,

thanks for your answer. I have started with the VISA-Vis (if I remember correctly) but at the moment I am not in the lab (or close to it) so I cannot check the corresponding vis. I will respond after I have checked this.

@nyc I have a manual which contains the commands (do you need them?)

[nyc_(is_out_of_here)]

You need to see what the TA command actually does.

[AlfK]

I had, of course, looked-up which command is the one I need to get the data out of the hp8559a/hp853a and I found the "TA" command to be useful. In the manual it says:
"TA Output trace A, decimal (ASCII values)"

Attached to this post you find a photography (sorry for the bad quality) of the corresponding entry from the manual. It does not give too much information...

[BillMe]

wow, a 32 year old SpecAn....that's got to be record in the forum. I'm not sure if HP (Agilent) had SCPI defined at that time, but does the manual show any commands to read the SpecAn status registers?

[nyc_(is_out_of_here)]

For an instrument that old, I might be tempted to use ibic.exe NI-488.2 Interactive Control to see how the instrument responds to multiple TA commands.

[JÞB]

Just chiming in without looking at the manual.  These antique instruments can be pretty touchy to get going.  One tip to look for in the manual: see if specifies addressing.  In the way-back days the HPIB cards expected to be set to untalk and unlisten to complete a "message transaction."  You may need to play around with the VISA GPIB Properties shown in this snippet Since modern instruments typically have some different default settings than what was common in that Pre-IEEE 488 era.