Re: [volt-nuts] volt-nuts Digest, Vol 83, Issue 11
http://boston.craigslist.org/bmw/ele/5687633175.html
On Tue, Jul 19, 2016 at 12:00 PM, volt-nuts-request@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@gmail.com
To: illya@xdevs.com, Discussion of precise voltage measurement
volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<
CANEyv6bhoQHdui3m9i_AbothnDG3rFATFqHDgzMJoPE69+G9UA@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@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.
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To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
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volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
--
John Phillips
Message: 2
Date: Mon, 18 Jul 2016 19:48:35 +0100
From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
drkirkby@kirkbymicrowave.co.uk
To: Discussion of precise voltage measurement volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<CANX10hCBO9MMxwaT0E6HbumWrP+pW3=
DkX4MQ88Ux2m3zKnOCA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
On 18 Jul 2016 17:34, "John Phillips" john.phillips0@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@gmail.com
To: Discussion of precise voltage measurement volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<CANEyv6a9Y_69qFSZnRVcEL4sKDAFsnx-PYw93=
YproE1hww+QQ@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@kirkbymicrowave.co.uk> wrote:
On 18 Jul 2016 17:34, "John Phillips" john.phillips0@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@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
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@gmail.com wrote:
http://boston.craigslist.org/bmw/ele/5687633175.html
On Tue, Jul 19, 2016 at 12:00 PM, volt-nuts-request@febo.com wrote:
Send volt-nuts mailing list submissions to
volt-nuts@febo.com
To subscribe or unsubscribe via the World Wide Web, visit
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
or, via email, send a message with subject or body 'help' to
volt-nuts-request@febo.com
You can reach the person managing the list at
volt-nuts-owner@febo.com
When replying, please edit your Subject line so it is more specific
than "Re: Contents of volt-nuts digest..."
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@gmail.com
To: illya@xdevs.com, Discussion of precise voltage measurement
volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<
CANEyv6bhoQHdui3m9i_AbothnDG3rFATFqHDgzMJoPE69+G9UA@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@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@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@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
--
John Phillips
Message: 2
Date: Mon, 18 Jul 2016 19:48:35 +0100
From: "Dr. David Kirkby (Kirkby Microwave Ltd)"
drkirkby@kirkbymicrowave.co.uk
To: Discussion of precise voltage measurement volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<CANX10hCBO9MMxwaT0E6HbumWrP+pW3=
DkX4MQ88Ux2m3zKnOCA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
On 18 Jul 2016 17:34, "John Phillips" john.phillips0@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@gmail.com
To: Discussion of precise voltage measurement volt-nuts@febo.com
Subject: Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit
multimeters.
Message-ID:
<CANEyv6a9Y_69qFSZnRVcEL4sKDAFsnx-PYw93=
YproE1hww+QQ@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@kirkbymicrowave.co.uk> wrote:
On 18 Jul 2016 17:34, "John Phillips" john.phillips0@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@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