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

Prologix support at prologix.biz
Tue Nov 27 23:19:27 EST 2007

Hello Chuck,

It appears that 3478A sends data continuously as soon as it is addressed to
talk. Since the Prologix adapter is busy processing GPIB data it is unable
to respond to USB commands. 

One solution is to turn read-after-write off (++auto 0) before connecting
the adapter to 3478A, and then use ++read command to read one measurement at
a time. Please see the manual (www.prologix.biz) for ++read command options.

The other option is to set 3478A to one-reading-per-trigger mode using "T3"
device command. See HP3478 manual (pages 39, 59). Then use the ++trg command
to trigger the device. ++auto must be set to 1 in this case.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Chuck Harris
Sent: Tuesday, November 27, 2007 7:34 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] OT: Prologix GPIB and HP3478A...

Hi Gang!

I just bought a Prologix GPIB <-> USB converter model, version 5.00,
and I am having some problems.  It works fine on some of my instruments,
but it just locks up when I hook it to an HP3478A DVM.  The DVM is
known good, and works great with my HP85B (doesn't everything?).

Basically, if I do any commands that require bus activity, the Prologix
locks up and refuses to respond to even the ++ver command.  When I unplug
the HP3478A, the Prologix once again finds its happy spot, and responds

Any ideas?

-Chuck Harris

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