[time-nuts] Off the wall: anyone with experienceprogrammingHP3456A?

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Sep 10 15:59:32 EDT 2005

In message <PKEGJHPHLLBACEOICCBJMEDNEIAA.jmiles at pop.net>, "John Miles" writes:

>The unfortunate truth is that GPIB is actually a pretty flaky thing.  It
>seems there is always a certain amount of swing-a-dead-cat empiricism
>involved with getting any complex GPIB hookup to work reliably.
>I can't talk to my Tek 492AP SA unless I turn on the 8566B or the 8657A that
>shares its GPIB bus, for instance, and I am fairly certain that all of my
>hardware and cabling is in good shape.

There are very strict limits to how many units you can have powered down
on an IEEE-488 bus and it depends on the bus topology etc.  It is also
pretty easy to violate the topology constraints if you don't stick
closely to star or line configurations.

It's all in the standard somewhere.

>It seems wise to keep GPIB programs as simple as possible, using as few
>features as you can.  Whenever I've tried to get fancy, I run into trouble.

That we can agree on.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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