[time-nuts] OT: Prologix GPIB and HP3478A...The Answer!

Chuck Harris cfharris at erols.com
Wed Nov 28 14:12:25 EST 2007

Hi John,

I agree in part.

If it is known that certain GPIB instruments are not supportable,
then it is essential to have that documented fact easily available to
the buyer.  Thus far, the Prologix website, and documentation, make no
mention of any possible limitations, or deficiencies.  [For instance, it
clearly cannot support the maximum defined GPIB system, or cable lengths.
That should have been mentioned.]

The GPIB standard is very well defined.  There really is no reason
to expect that a commercially made controller wouldn't be able to operate
with any GPIB controlled instrument.  The HP87B's controller will operate
any device, and I am sure that the controllers I designed as a graduate
student would as well.

I would be angry, except that I already knew that the design had a major
short cut in it before I bought my Prologix.  If you recall, I addressed
that issue many months back on this forum.

I bought my Prologix controller based on the good reports that all of
you guys posted.  And the need to control a single device, a Tektronix
7854.  It will do that, so I am satisfied.

The "Go away kid, you bother me!" approach won't win over many

-Chuck Harris

John Miles wrote:
> Interesting point there.  I seem to recall quite a few pullup/pulldown
> options in the Atmel port-configuration registers; this may just be a matter
> of selecting a mode that looks more like the resistor configuration Chuck
> mentioned.
> Personally, I think it's fine if you support only 99% of the GPIB devices
> out there and leave the remaining 1% to the competition.  Your boards have
> proven compatible with an incredibly-wide array of instruments at this
> point.  If the 3478A problem can't be fixed in software, I think the best
> answer is, "Sorry, we don't support that one, here's a refund."  It
> certainly isn't worth adding more chips (and cost) to the board IMHO.
> -- john, KE5FX

More information about the time-nuts mailing list