Error 4.2 when scanning an HP 5334A by MAX4.0

[Alex Wu]

I'm trying to scan an instrument HP5334A by MAX4.0, but I failed to find it. I'm using a NI PCI-GPIB card on my PC. I am sure the GPIB works well. The address of HP5334A is unique (07). When MAX scanned it, I found that the REM LED on 5334A was on, LEDs of Talk and Listen were flashing. Then the HP5334A gave Error 4.2, which means: Alpha character expected. And MAX showed that all of 32 devices is HP5334A with address of 07 when I connected only one HP5334A to the GPIB.

Any suggestion are really appreciated, Thanks

[GoBlue]

Thanks for posting this Alex, I've seen the same problem and have been meaning to post it myself.  It also happens on the HP535x series of counters too.  It appears to have broken somewhere in the MAX3.0 and higher, I had an older verison, I believe 2.1, and it worked everytime.  I have NI spy captures of both good and bad GPIB scans, if that would help anybody.

[Alex Wu]

Thank you for sharing your experience with me, Goblue. Do you have any problems of communicating with this device when MAX2.1 is installed? Thanks

[Chris_R.]

Hi Alex,
I am not familiar with your particular instrument, but is there a way to chang the address of the instrument on the instrument itself?  (ie. dip switches or buttons on the instrument or the instrument's user interface).  The behavior you are seeing often is a result of addressing conflicts.  I know you said you were using a unique address, but try a different one, set on the instrument itself and not through the PC, and see if you still see the same behavior.  Even though you may have set a unique address, there may still be a conflict that you don't know about.  Please try this and let me know if it helps.  If it doesn't, please send any updates and I will look into the issue further for you.  Good luck and have a great day!

Chris R.
Applications Engineer
National Instruments

[GoBlue]

It's a wierd one...  I could always talk to the instrument, using both MAX 2.1 and higher, unless I did a scan for GPIB instruments on MAX 3.0 and higher.  Once I did the scan on MAX 3.0 and higher, I would have to power cycle the instrument to get it to talk again.  When I was troubleshooting the problem I ended up connecting just the counter, either the HP 5334A or 5350, to the bus and doing the scan.  I initially thought I had a bad counter, that's why I tried both models.  I also tried changing the address, and that gave me the same result.  I'll attach some NI Spy dumps, one of a good scan, and one of a bad scan.  They didn't help me much, but maybe they might mean more to you.

[JoshuaP]

If you look at the spy captures and compare the return results from the FindLstn call on line 11 you will notice that the good one returns (0x0000 and 0x0009) and the bad one returns (0x0000, 0x6009, 0x6109,...) 32 listeners. I'm not sure what this means, do you have 32? Otherwise I would disconnect one instrument at a time and check for a bad cable or a bad instrument that is throwing everything else off.

-Josh

[ScottieB]

It appears that this particular instrument has 32 secondary addresses that it responds to, which is why you see all these instruments show up in MAX.  Also, the "Scan for Instruments" button attempts to send "*IDN?" to every instrument on the bus, which may be confusing the 5334A, causing the need for a power cycle.  You don't really need to do a "Scan", it's just a diagnostic tool.  Simply communicate with your instrument without first performing a scan using LabVIEW or IBIC.

Scott B.

GPIB Software

[GoBlue]

I have an USB to GPIB adapter, so I connected the adapter directly to the GPIB connector.  So, there were no additional GPIB cables or equipment, just the adapter and counter.  This has happened on several computers and adapters, I actually didn't believe the guys in the field until I saw it myself.

[Chris_R.]

Hi GoBlue,

As Scott mentioned above, seeing 32 instruments doesn't necessarily mean you have 32 instruments physically attached to the bus.  The 32 secondary addresses the instrument has seems to be causing this to happen.  If you do not Scan for Instruments, does your device still work properly in your application software?  If so, then you may not be able to use Scan for Instruments in MAX when that particular instrument is attached.  I have heard of this same issue with other instruments (by different manufacturers) and the manufacturer of the instrument was working on a solution.  You may want to contact HP and see if this is a known problem and if there is a fix for it.

Let me know if you have any other questions!  I will be happy to help.

Chris R.
Applications Engineer
National Instruments