Babbling HP6624A when communicating through GPIB-232CV-A

[Johan Zeylon]

I have an application where i use a GPIB-232CV-A to connect a HP6624A to a serial port of a controlling computer.
When i replaced the 6624 i found out that some of them behave strangely.
The normal behaviour is that if i send a command i will get the answer back and nothing else.
Something like:
>"ID?"
<"HP6624A"

With another 6624 i get a never ending stream of linefeeds after the answer.
Something like:
>"ID?"
<"HP6624"
<"[LF]"
<"[LF]"
<"[LF]"
<"[LF]"
<"[LF]"
...

If i communicate directly with the instrument using GPIB everything seems OK.
I'm suspecting that it has something to do with the firmware version in the 6624.
I have attached a log of the GPIB communication between the GPIB
-232CV-A and the HP6624A.

Any hints or suggestions?

[Jimmie_A.]

Hello!

Sounds like a rather odd problem but I will try to give you a couple of hints and tips in order to help you troubleshooting.

You said that direct GPIB worked fine, but when using the 232cv it seems like it sends extra linefeeds? Do the instruments itself have the same settings? They might have different handshaking setups, and due to this they are stuck in a loop waiting for the 232cv to answer it, and when it doesn�t do that the instrument will send out linefeeds in a never ending stream?

Check the settings on the instruments and make sure that these are exactly the same + having the same firmware since older ones might have bugs and so on.

Finally check the serial port settings on your computer (the communication settings)

Hope this help!


Cheers,
Jimmie A.
Applications Engineer
National Instruments

[Johan Zeylon]

I have swapped the PSU:s and tried newer ones with more recent firmware.
ROM version 2839 doesn't work.
ROM version 3833 works.

This confirms that is has something to do with the firmware version as i suspected.
I still don't know _why_ it didn't work with older firmware. I have contacted Agilent but haven't got an answer yet.

/Johan