[volt-nuts] GPIB Issue with 3458A
randyevans2688 at gmail.com
Sun Dec 31 13:46:05 EST 2017
The routine looks like this on the Output Console:
The 0 pops up after several seconds and the 1 after even more seconds
later. No other output after the 1.
The temperature reading is OK but no voltage readings.
Thanks for the assistance but I likely have a hardware issue. I did the
service note 13A test and the unit passed it fine. I will have to do more
troubleshooting on my own but I really appreciate the help.
On Sun, Dec 31, 2017 at 6:09 AM, Todd Micallef <tmicallef at gmail.com> wrote:
> I put together a quick script for testing your connection. I have emailed
> it to you but attached it here for others if needed. It will be easier than
> running the other program.
> On Sun, Dec 31, 2017 at 9:00 AM, Dr. Frank <frank.stellmach at freenet.de>
> > Randy,
> > I doubt, that your hp unit is defective, as it might work under certain
> > circumstances, and also the FW version 8.2 vs. 9.2 will not make any
> > difference, as only a few pair of bytes are different. All versions of
> > A5 board are designed to be completely interchangeable over all versions
> > 3458A instruments.
> > I have another theory, which deals with the hardware version difference
> > between the agilent and the hp unit.
> > Your agilent unit might already have the 66547, full SMD board for A5,
> > whereas the hp will for sure have one of the old 66505/515, through- hole
> > boards, Rev A, B, or C. Illya has all of them pictured in his first 3458A
> > repair blog.
> > All the old versions (A, B, C) have GPIB bus transceivers, TI 75ALS160
> > for the data bus, and NS 75161 for the handshake signals.
> > The new SMD board has TI 75ALS160 / TI 75ALS161, instead.
> > So, the handshake bus uses a different logic family for the new board,
> > therefore, the logic levels / immunity might be slightly different.
> > My hp3458A has got the REV C A5 board, and it's from 2000.
> > Since 2009, I run a similar datalogging program for capturing LTZ1000
> > output versus time, each 4 seconds, on an old PC with WIN98, Turbo
> > an XT bus GPIB card from CEC, with the NEC chip.
> > This program and hardware ran properly for years, (decades), until more
> > and more errors during the 24h acquisition runs occured, vaguely
> > me of your trouble.
> > The output values were always correct, but frequently, 10sec time-outs
> > ocurred, giving zero readings in the datalog. This time-out is obviously
> > related to the handshaking mechanism.
> > Finally, I found out, that the old ATX PSU was failing, especially its
> > input snubber network was gone defect, which probably created big EMC
> > spikes.
> > After replacing the PSU, all these errors vanished completely.
> > My conclusion was, that the GPIB bus is susceptible to such EMC
> > disturbances, although it's solid TTL logic.
> > As obviously the handshake signals were affected only, their higher
> > susceptibility to disturbances may be caused by the difference in the
> > family of the transceiver IC. The agilent 3458A might be more tolerant to
> > that, having the ALS161 version, instead.
> > So you might also look for EMC problems in your lab, like SMPS, LED
> > or a defective PC power supply.
> > Maybe, these Prologix adaptors (clones?) have critical logic levels,
> > especially on the handshake bus, or an improper ground.
> > You might search for these signal problems directly on the GPIB cable.
> > Frank
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