[volt-nuts] volt-nuts Digest, Vol 83, Issue 11

Chris caall99 at gmail.com
Tue Jul 19 12:02:56 EDT 2016 

meant to say that these: Agilent 3458A, Datron 4000A, and Datron 4708 are
for sale here: http://boston.craigslist.org/bmw/ele/5687633175.html

On Tue, Jul 19, 2016 at 12:02 PM, Chris <caall99 at gmail.com> wrote:

> http://boston.craigslist.org/bmw/ele/5687633175.html
>
>
> On Tue, Jul 19, 2016 at 12:00 PM, <volt-nuts-request at febo.com> wrote:
>
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>> Today's Topics:
>>
>>    1. Re: Keysight 3458A vs Keithley 2002 8.5 digit     multimeters.
>>       (John Phillips)
>>    2. Re: Keysight 3458A vs Keithley 2002 8.5 digit     multimeters.
>>       (Dr. David Kirkby (Kirkby Microwave Ltd))
>>    3. Re: Keysight 3458A vs Keithley 2002 8.5 digit     multimeters.
>>       (John Phillips)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Mon, 18 Jul 2016 09:34:18 -0700
>> From: John Phillips <john.phillips0 at gmail.com>
>> To: illya at xdevs.com,  Discussion of precise voltage measurement
>>         <volt-nuts at febo.com>
>> Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
>>         multimeters.
>> Message-ID:
>>         <
>> CANEyv6bhoQHdui3m9i_AbothnDG3rFATFqHDgzMJoPE69+G9UA at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Most labs never turn 3458As off. The longer they are on the lower the
>> drift
>> rate. I would rather have an 20 year old meter with new batteries than a
>> new meter.
>>
>> On Mon, Jul 18, 2016 at 4:11 AM, Illya Tsemenko <illya at xdevs.com> wrote:
>>
>> > Well, it's the topic many can go on and on about.
>> > As with everything there are specific cons and pros of both units, but
>> > here are my 5c:
>> > + K2002 is smaller, lighter (4kg vs 10kg), less powerhungry (sometimes
>> > it's important if you send unit for cal overseas, or take to remote
>> site).
>> > + K2002 can support scan cards (standard, or low-EMF ones) via expansion
>> > slot
>> > + K2002 DCI/ACI goes up to 2Amps
>> > + K2002 goes bit higher on ACV frequency (15MHz, but performance there
>> is
>> > so-so)
>> > + K2002 natively supports thermocouples, RTDs, SPRT thermal sensors and
>> > custom settings
>> > + K2002 supports rare rainbow unicorn nanovolt preamplifier Keithley
>> 1801
>> > (substitute can be bodged up but that's not beginner's project)
>> > - Old K2002's require capacitor replacements (units with S/N 06xxxxx and
>> > 05xxxxx). Mandatory! Meters from 2005+ year have S/N starting with
>> 11xxxxx
>> > - Readings noisier than 3458A
>> > I have two units in use, and have worklogs for both :
>> > https://xdevs.com/review/kei2002/ - newer K2002 from year 2007
>> > https://xdevs.com/fix/kei2002_u2/ - older K2002 from 1994 which was
>> > repaired after capacitor leak damage.
>> > Service of these Keithley meters (and 2001, which are very similar
>> design)
>> > is not complicated, but require attention and knowledge what you doing.
>> > There only few custom parts used.
>> >
>> > Now regarding industry standard 3458A. Reason why you saw only 3458A in
>> > metrology lab is simple:
>> > Superior ADC (many rightfully think it's best on market, ever), amazing
>> > linearity (JJA was required to test linearity with good confidence),
>> very
>> > easy calibration (just need 10V reference and 10KOhm standard resistor
>> to
>> > get 3458A calibrated to uncertainty of used standards), Artifact
>> > calibration (ACAL) to significantly remove impact of temperature
>> variation
>> > on accuracy, proven performance. Many labs use 3458A as main transfer
>> > standard due to it's ADC performance.
>> >
>> > It comes at cost though, as key components of meter's A/D are custom
>> > hybrids. Meaning if you got sour pill, and A/D drifting, you will have
>> to
>> > replace expensive A/D board. Newer Agilent/Keysight branded 3458A's are
>> > essentially same boxes, just with newer hardware and likely with new
>> > FPGA-based digital brains. Performance is same though, unless you really
>> > getting early 1990's meter. Many design issues and items I got covered
>> in
>> > my repair worklog: https://xdevs.com/fix/hp3458a/
>> >
>> > Brief 10V comparison : https://xdevs.com/datalog_tcomp/ - sampling 10V
>> > connected to 2001+2002+3458A
>> > Some of the A/D noise comparisons (meter input shorted) -
>> > https://xdevs.com/article/dmm_noise/
>> >
>> > So decide what fit best your needs. 3458A is overall higher performance
>> > instrument, but in lot of applications outside of metrology it's
>> > performance benefits may not cover up for higher price and size. Both
>> 3458A
>> > and 2002 are still supported and sold new by manufacturers. Regular
>> > calibration of these is likely be over 1000$USD, and lab-grade
>> calibration
>> > for 3458A is usually in range of 2600$USD.
>> >
>> > P.S. there are also few other 8.5d meters, but much less information
>> > available on those, as less people have them. Only "modern" 8.5d meter
>> is
>> > 8508A, which cost even more than 3458A without much performance
>> improvement.
>> >
>> > 18/07/16 17:54, Dr. David Kirkby (Kirkby Microwave Ltd) пишет:
>> >
>> > I am interested to hear people's view on the relative merits  of the
>> >> HP/Agilent/ Keysight 3458A vs the Keithley 2002.
>> >>
>> >> I noticed that when I recently visit the standard lab for voltage at
>> NPL,
>> >> the place was littered with Agilent 3458As, but I did not notice a
>> single
>> >> Keithley 2002. But maybe NPL get better discounts from HP/Agilent
>> Keysight
>> >> than Keithley/Tektronix.
>> >>
>> >> I notice that the used prices of 3458A is higher than 2002s.
>> >>
>> >> Also, are there any things ons should be looking out for when buying a
>> >> 3458A or 2002? I have in the past thought an Agilent front panel was a
>> >> better than an HP one, as it would not be as old, but this is not
>> always
>> >> true - see my comment later.
>> >>
>> >> What S/N are best avoided? Does anyone have a record of S/Ns of
>> Keighley
>> >> meters with time?
>> >>
>> >> Very recently I had a somewhat scruffy HP 6674A PSU with a damaged
>> LCD. It
>> >> cost me $50 or so to pick up a clean Agilent front panel with a new
>> >> display.  The display actually turned out to be unsuitable,  yet my
>> >> Agilent
>> >> badged 6674A is actually a fairly old HP unit.  So white my intention
>> was
>> >> not to rebadge the PSU, that happened as a result of a legitimate
>> reason
>> >> to
>> >> get it working. So this really indicates how an old HP 3457A could be
>> made
>> >> to look a newer Agilent one.
>> >>
>> >> Dave.
>> >> _______________________________________________
>> >> volt-nuts mailing list -- volt-nuts at febo.com
>> >> To unsubscribe, go to
>> >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> >> and follow the instructions there.
>> >>
>> >
>> >
>> >
>> > _______________________________________________
>> > volt-nuts mailing list -- volt-nuts at febo.com
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>> >
>>
>>
>>
>> --
>>
>> *John Phillips*
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Mon, 18 Jul 2016 19:48:35 +0100
>> From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
>>         <drkirkby at kirkbymicrowave.co.uk>
>> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
>> Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
>>         multimeters.
>> Message-ID:
>>         <CANX10hCBO9MMxwaT0E6HbumWrP+pW3=
>> DkX4MQ88Ux2m3zKnOCA at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> On 18 Jul 2016 17:34, "John Phillips" <john.phillips0 at gmail.com> wrote:
>> >
>> > Most labs never turn 3458As off. The longer they are on the lower the
>> drift
>> > rate. I would rather have an 20 year old meter with new batteries than a
>> > new meter.
>>
>> If one buys a used meter, one has no idea if it has been switched on very
>> occasionally or on 24/7.
>>
>> Do you keep your meter powered up during the transit between your lab and
>> the cal lab? I would think that quite difficult if you used a courier,
>> but
>> not a problem if it was taken in a car.
>>
>> Dave.
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Mon, 18 Jul 2016 12:39:33 -0700
>> From: John Phillips <john.phillips0 at gmail.com>
>> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
>> Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
>>         multimeters.
>> Message-ID:
>>         <CANEyv6a9Y_69qFSZnRVcEL4sKDAFsnx-PYw93=
>> YproE1hww+QQ at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> We do not keep them powered up for transit.
>> All the meter gets more stable with age. The reference gets more stable
>> with burn in.
>> We store 3458As energised even when we do not plan to use them for a
>> while.
>> Most 10 year old meters are as stable as the new meters with the high
>> stability option.
>> I do not have any stats but quite often we would buy an old meter that had
>> a old cal sticker and find that 10 volse was still in spec.
>>
>>
>> On Mon, Jul 18, 2016 at 11:48 AM, Dr. David Kirkby (Kirkby Microwave Ltd)
>> <
>> drkirkby at kirkbymicrowave.co.uk> wrote:
>>
>> > On 18 Jul 2016 17:34, "John Phillips" <john.phillips0 at gmail.com> wrote:
>> > >
>> > > Most labs never turn 3458As off. The longer they are on the lower the
>> > drift
>> > > rate. I would rather have an 20 year old meter with new batteries
>> than a
>> > > new meter.
>> >
>> > If one buys a used meter, one has no idea if it has been switched on
>> very
>> > occasionally or on 24/7.
>> >
>> > Do you keep your meter powered up during the transit between your lab
>> and
>> > the cal lab? I would think that quite difficult if you used a courier,
>> but
>> > not a problem if it was taken in a car.
>> >
>> > Dave.
>> > _______________________________________________
>> > volt-nuts mailing list -- volt-nuts at febo.com
>> > To unsubscribe, go to
>> > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> > and follow the instructions there.
>> >
>>
>>
>>
>> --
>>
>> *John Phillips*
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
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>> ------------------------------
>>
>> End of volt-nuts Digest, Vol 83, Issue 11
>> *****************************************
>>
>
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