[volt-nuts] Voltage standard spotted for sale, 4410

[roman's ebay]

Hi All
Newcomer to the list. Been watching it since I came across it about a month
ago. Didn't realise that I wasn't the ONLY person in the world obsessed with
having an accurate volt in my back yard for no reason other than that I
can.....:-)

This discussion about the Statronics VS4 particularly got my interest. I
have one courtesy of fleabay about 4 years ago, for the princely sum of $20
plus delivery (mine was the only bid, which (together with the quad Standard
Cell box for about the same) is why I thought I was alone...).  The VS4 (and
indeed the Standard Cell Box) appears to work very well and all outputs have
maintained their relativity over that time within the limits of my
measurement patience, even after about a year powered down after I moved
house. Plan to start doing some serious tracking real soon now.

Each of the 4 independent cells in the VS4 consist of 8 selected, matched
and aged LM329s with matched resistors (all off the same reel of Evanohm,
selected mica cards, etc), low drift amps etc all contained in a controlled
oven. The Statronics stability spec is -2 +-2ppm per year (after year one).
The unit was conceived and designed by the CSIRO who run (or at least ran)
the Australian National Measurement Laboratory, so I would guess that the
spec is conservative. If Will is correct about  the Gould 4410/Fluke 732A,
these must be pretty good devices. I suspect I won't get one of them for
$20!

I saw Ben's question about the manual, and Tom's response about the 100 page
masters thesis. That would be interesting to read!  I have a copy of the
Statronics VS4 Instruction Manual Issue 2 which is only about 70 pages, half
of which is a treatise on statistical intercomparisons and a HP-85 Basic
program. But the first 38 pages contain what I would expect - user
instructions, design descriptions, schematics, etc. Unfortunately, I don't
have an electronic copy, nor ready access to a scanner. 

Ben, I note you are in Australia. Whereabouts? I am in Adelaide. Maybe I can
get the hard copy to you some way.

Roman



-----Original Message-----
From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
Behalf Of Will
Sent: Tuesday, 12 August 2014 5:40 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Voltage standard spotted for sale, 4410

2014-08-12 1:25 UTC+03.00, Tom Knox <actast at hotmail.com>:
> I am not sure the use of LM329's was a cost saving measure or 
> compromise, actually the 4410 uses a different approch, it's basicly is a
big oven.
> Guildline has been a Metrology leader for decades and  has been a 
> leader including  temp measurements and oil baths so I for one would 
> be interested in how well their approach to a voltage standard performs.

The 4410 was not designed or manufactured by Guildline. Just like many of
the products sold under their brand name.

At the time of design the LTZ1000 was not yet available and the Fluke ref
amp was obviously property of Fluke only. The only same level technology
available to all manufactueres was the 1N829 zener which if carefully
selected and matched can be as good as LTZ1000. Datron calibrators with
multiple selected, aged and matched 1N829 zeners are a good example of that.

The original 100 page (Statronics) documentation seems to be a masters
thesis rather than a product manual and has a detailed description of the
design process. The text mentions that the 1N829 temperature compensated
zeners were discarded because of the poor availability in Australia where
the unit was developed. The LM399/LM329 series was selected because it was
the "best available". Band-gap type references were also evaluated but found
unsatisfactory at the early stage.
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