[volt-nuts] Traveling Standards

Wed Aug 31 22:17:28 UTC 2011

For starters the 3458A is still officially a "supported" product ( by 
Agilent) , meaning you can still buy replacement parts and boards 
directly from Agilent...not inexpensive mind you

Dave
NR1DX

On 8/31/2011 5:11 PM, Laurence Motteram wrote:
> I am just curious; WHY is there a constant supply of 3458A reference boards?  Where do they all come from?
>
>
> Regards,
>
> Laurence Motteram
>
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On Behalf Of Electronics and Books
> Sent: Thursday, 1 September 2011 12:26 AM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] Traveling Standards
>
> There is a constant supply of the reference board of a hp 3458A multimeter. Only a power supply is needed. There are not 10V but stable.
>
>   
> Met vriendelijke groeten
> Regards
>
>
> Frans
>
>
> ElectronicsAndBooks at Yahoo dot com
>
> From: Demian Martin<demianm_1 at yahoo.com>
>
> To: 'Bob Smither'<smither at c-c-i.com>
> Cc: volt-nuts at febo.com
> Sent: Wednesday, August 31, 2011 3:58 AM
> Subject: Re: [volt-nuts] Traveling Standards
>
> Bob:
> To make a real PPM standard has so many technique pitfalls that it may be a
> really frustrating experience. The late Jim Willians wrote something about
> this in a article on checking precision DAC's. Even with the best stuff a
> real climate controlled environment is more than most of us are able to do.
> If you look at the manuals and construction efforts for these things there
> is a lot of experience in details that's hard to just copy. Even the circuit
> layouts and managing the thermocouples in all the connections is not
> trivial. Here is a good starting point for understanding it:
> http://cds.linear.com/docs/Application%20Note/an74f.pdf
>
> Here is an alternate offer I'll make. I just checked and I have 3 Fluke
> 731b's that I'll be happy to provide for travelling standards. They are
> doing nothing but occupying space on a shelf for now. I also have a 732A, a
> Prema DVM and a Fluke 8506a, all of which use LTZ1000 references. Those
> three have tracked each other within 50 ppm for the last 5 years without
> attention. Probably none have been calibrated in the 21'st century and only
> the Flukes have a common origin. Prema makes their own JJ standards. I'll
> fire up the 3 731b's and check them against the trio to get things started.
> I'll get them boxed in a nice reusable shipping case if you will pick up the
> shipping to start this off. They may need service (the batteries are
> probably shot by now), I'll leave that to you. I don't have time for more
> with my "day" job.
>
> If this is interesting send me a note directly and I'll get it started.
>           Demian
>
> Date: Mon, 29 Aug 2011 22:52:24 -0500
> From: Bob Smither<smither at c-c-i.com>
> To: Discussion of precise voltage measurement<volt-nuts at febo.com>
> Subject: Re: [volt-nuts] Traveling Standards
> Message-ID:<4E5C5E78.6020109 at c-c-i.com>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
>
> Fellow Voltage Fans,
>
> To review - I would like to have a lab standard here that I can trust to
> 10 ppm or better to use to calibrate my expanding collection of
> voltmeters.  I have proposed to built a portable standard that I will
> ship to participating volt nuts on this list who will record their
> readings of the standard and share those readings with the list.
>
> I have designed a Traveling Standard that incorporates two references
> (an LM199AH and a MAX6350E) along with an LM34 to measure the
> temperature of the MAX6350 (the LM34 is glued to the top of the MAX6350.
>
> The schematic is attached to this page:
>
>    http://www.c-c-i.com/TS
>
> Following suggestions on this list (thanks!) I will use an external
> "wall wart" supply for the input 24 Volts.  This reduces any shift
> caused by the line regulation of the three terminal regulator.
>
> My design notes are included on the above page.
>
> I have constructed a bread board of the circuit on a plugboard.  I will
> move the circuit to a printed circuit version after some testing.
>
> Some preliminary readings from the breadboard of the LM199AH part are
> noted on this page:
>
>    http://c-c-i.com/node/121
>
> Note that these readings are taken with an HP3455A which has not been
> calibrated since I bought it new.  I would expect the accuracy to be no
> better than .01% and may be much worse.
>
> My plan is to mount the printed circuit board version in a short length
> of 2" PVC pipe with connectors for the three outputs.
>
> After the printed circuit board version is aged some it will be ready to
> ship.
>
> Are there any more on the list that would be willing to make a
> measurement of the Traveling Standard?
>
> I will collect the readings that we collectively get on the TS and make
> them available to the list.  I anticipate that with some experience we
> can all benefit from having this TS well aged and with a well known
> output voltage.
>
> I will handle the shipping - all I ask is that you take careful
> measurements and provide them to me, then return the unit.
>
> Thanks!
>
> ****************
>
>
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-- 
Dave&  Lynn Henderson
Manuals at ArtekMedia.com
www.Artekmedia.com
PO Box 175
Welch,MN 55089