Joe, you actually make a good point. Right now the 3457A has my full confidence as it stands. I've not seen a single reading from it that I even slightly question. I had a few misunderstandings, but nothing which was the meters fault. It agrees with all my other meters well within their own spec and it also agrees with many semi precision devices I have floating around. It's absolutely spotless inside and in really good shape outside as well. It was still sealed from the last calibration by Tektronix with no signs of abuse and the cal count was 34. So with that all said I think I'm going to avoid getting any kind of reference at the time and work on getting some more cash together to send it off to Agilent. The before and after can be checked and if I'm confident in the results I can calibrate my lesser meters to match. I then have 5 points of reference to watch for drift issues.
Ohh and most important of all, the 3457A agrees with itself on each range to the limits of noise. That in itself tells me it's at least not aged unevenly. The noise is not much of an issue anymore as well since I learned a few tricks. It's got repeatability which is a very important part.
Thanks,
Jeff
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On 1/6/2013 6:27 PM, J. L. Trantham wrote:
You can never have too many meters. It's like your wife's shoes.
However, you need to pick one of the litter to send to whomever for a formal
calibration. I opt for sending them to their respective manufacturers.
That's why I think you should send the 3457A to Agilent. You will get the
'before' and 'after' data that will either give you great confidence in the
meter or shake your faith to the core, until you send it back to Agilent in
a year for another round of 'before' and 'after' data.
I have two HP 3458A's and two Solartron 7081's that have been to their
respective manufacturers (HP and Ametek, twice for the Solartrons) for
calibration. Reading a Fluke 731B that I obtained from theBay, set to 10 V,
they are within about 15 uV of each other and quite close to 10.000000 VDC.
Therefore, I conclude that the 731B is 'accurate' and the meters are
calibrated. I don't think I can get any closer than that without building
my own environmental facility and reference. Not likely as a hobby.
However, I now have the 'tools' to do a good calibration of some HP 432A
power meters and their calibrators plus a load of other items.
Enjoy!!!!!! And I hope you get to see your family from time to time. :^)
Joe
-----Original Message-----
From: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>] On Behalf Of Jeff Machesky
Sent: Sunday, January 06, 2013 7:04 PM
To: hp_agilent_equipment@... <mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457A and other meter low resistance
tips?
Too funny. Well I've already got 5 meters of decent quality and I'm looking
for more. It's also sad when I'm building up power supplies to get 1000v DC
and 1000V AC at various frequencies to calibrate items like the DMM on my
2465BDM. I don't need 1000, buy hey I figured I may as well have overhead.
Think those little gator clip wires from ebay are safe at 1000v, lol. I've
already managed to kill 1000 piv rated diodes.
I also partake in the crazy practice of joining my fixed 1000v supply with
my 30 volt isolated lab supply to tweak to precise high voltages.
Pretty stupid practice..but someones got to do it. The only saving grace is
the current is at least limited to about 100ma..not that it would save me.
I have the dilemma that if I get a calibrated voltage reference and it
disagrees with the 3457A then I'll naturally have to do one of two things.
Send it off to Agilent to get the meter calibrated, or self calibrate so the
3457A agrees with my reference. The ladder has the advantage of not having a
reference around that disagrees with the meter. If I send it off to Agilent
I'll always question who was right, did the tech do a sloppy job..etc..etc.
Ohh and the ranges also have to exactly agree with each other or it's back
for calibration. Surprisingly they do now.
Insanity is doing the same thing over and over and expecting different
results. Wonder how that plays in with calibration.
Jeff
On 1/6/2013 5:02 PM, Don Black wrote:
he only sure way is to stick your finger in the light socket and guess.
Don Black.
On 07-Jan-13 10:08 AM, Dave Daniel wrote:
Unless all three voltmeters disagree. Then he needs n more until at
least two agree. Then again, what if more than one pair agree, but
with different values? Then I guess he needs a fifth meter which
agrees with one of the pairs which agree.
As you said, it's addicting and it makes my brain hurt.
Dave
On 1/6/2013 3:38 PM, J. L. Trantham wrote:
A man with one voltmeter knows what the voltage is. A man with two
is never quite sure. Therefore he needs a third. :^)
Careful. This stuff is addicting.
Joe
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
] On Behalf Of Jeff
Machesky
Sent: Sunday, January 06, 2013 2:58 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] 3457A and other meter low
resistance
tips?
Thanks again for the info.
Hmm, to join such a group and come in as a total newb might be a
bit of
a humbling experience. Then again I have to admit I'm enjoying
attempting to get the precision. Even just working with the Hamon
dividers and monitoring temperatures and matching resistors to
precision
is kind of entertaining. It's however not very productive. I'm
very clear with my wife that my "hobby" is all about learning for
me, it's not about trying to improve the garage door opener. Once
in a
while I'll
make something cool that gets used, but it's not my goal. I may
join them just to get an education on what I'm clueless about from
their point of view.
Thanks,
Jeff
On 1/6/2013 1:32 PM, Steve Byan wrote:
On Jan 6, 2013, at 3:07 PM, J. L. Trantham jltran@...
<mailto:jltran%40att.net>
wrote:
It's called 'volt-nuts'.
More fully, the volt-nuts mailing list -- volt-nuts@...
<mailto:volt-nuts%40febo.com>
To subscribe, go to
Best regards,
-Steve
-----Original Message-----
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
] On Behalf Of Jeff
Machesky
Sent: Sunday, January 06, 2013 1:08 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: Re: [hp_agilent_equipment] Re: 3457A and other meter
low
resistance
tips?
Do they have a club for people with a certain number of digits
on their multimeters. I feel they should as it's a
whole new
world.
--
Steve Byan stevebyan@... <mailto:stevebyan%40me.com> >
Littleton, MA 01460
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