Empathy List Archives

DC

David C. Partridge

Tue, Mar 20, 2012 3:47 PM

I just recently managed to buy a spares unit for my 5200A.

I'm delighted to report that between the two units, and after a bit of trouble de-soldering edge connectors, I now have a working, quiet (old fan was DEAFENING), but uncalibrated AC calibrator.

Checking the output is against my 7081, here is what I'm see on the 1V range set for 1V (the other ranges show a very similar pattern):

Frequency Reading Error
50Hz 1.00371 .371% <--- Surprisingly high
100Hz 1.00091 .091% <--- Surprisingly high
500Hz .99993 .007%
1kHz .99990 .010%
5kHz .99991 .009%
10kHz .99991 .009%
50kHz 1.00004 .004%
100kHz 1.00003 .003%
500kHz .99718 .282%
1MHz .98859 1.140% <--- This seems very high

Comparing the results against a 7150Plus which was connected in parallel, I get a different story:

Frequency Reading Error
50Hz .99993 .007% *** see below
100Hz .99989 .011%
500Hz .99991 .009%
1kHz .99991 .009%
5kHz .99993 .007%
10kHz .99993 .007%
50kHz 1.00028 .028%
100kHz .99933 .077%

Substituting a 7151 for the 7150Plus I get:

Frequency Reading Error
50Hz .99986 .014% *** see below
100Hz .99992 .008%
500Hz .99997 .003%
1kHz .99997 .003%
5kHz .99997 .003%
10kHz .99995 .005%
50kHz 1.00002 .002%
100kHz .99895 .105%

These figures are quite impressive for the 7150Plus and the 7151 as the 24 hour figures for the 7150Plus are 40Hz-10kHz range are .03% + 15 counts and the one year figures are .07% + 15 counts. The 7151 figures are similar.

(***) I was only able to get a stable reading at 50Hz by grounding the low output of the calibrator. I'm not quite sure what the problem is here.

If I believe the 7150Plus or the 7151, the calibrator is correct within the limits of the meters' accuracy.

If I believe the 7081, the calibrator is way off at the low end and high end of the frequency ranges.

Hmmmm ...

Does anyone have any suggestions as to why the 7081 seems to read so high at 50Hz, 100Hz and 1MHz, and whether the calibrator is wrong or the 7081?

Oh dear, life was so much simpler when I only had one clock!!!

Dave

I just recently managed to buy a spares unit for my 5200A. I'm delighted to report that between the two units, and after a bit of trouble de-soldering edge connectors, I now have a working, quiet (old fan was DEAFENING), but uncalibrated AC calibrator. Checking the output is against my 7081, here is what I'm see on the 1V range set for 1V (the other ranges show a very similar pattern): Frequency Reading Error 50Hz 1.00371 .371% <--- Surprisingly high 100Hz 1.00091 .091% <--- Surprisingly high 500Hz .99993 .007% 1kHz .99990 .010% 5kHz .99991 .009% 10kHz .99991 .009% 50kHz 1.00004 .004% 100kHz 1.00003 .003% 500kHz .99718 .282% 1MHz .98859 1.140% <--- This seems very high Comparing the results against a 7150Plus which was connected in parallel, I get a different story: Frequency Reading Error 50Hz .99993 .007% *** see below 100Hz .99989 .011% 500Hz .99991 .009% 1kHz .99991 .009% 5kHz .99993 .007% 10kHz .99993 .007% 50kHz 1.00028 .028% 100kHz .99933 .077% Substituting a 7151 for the 7150Plus I get: Frequency Reading Error 50Hz .99986 .014% *** see below 100Hz .99992 .008% 500Hz .99997 .003% 1kHz .99997 .003% 5kHz .99997 .003% 10kHz .99995 .005% 50kHz 1.00002 .002% 100kHz .99895 .105% These figures are quite impressive for the 7150Plus and the 7151 as the 24 hour figures for the 7150Plus are 40Hz-10kHz range are .03% + 15 counts and the one year figures are .07% + 15 counts. The 7151 figures are similar. (***) I was only able to get a stable reading at 50Hz by grounding the low output of the calibrator. I'm not quite sure what the problem is here. If I believe the 7150Plus or the 7151, the calibrator is correct within the limits of the meters' accuracy. If I believe the 7081, the calibrator is way off at the low end and high end of the frequency ranges. Hmmmm ... Does anyone have any suggestions as to why the 7081 seems to read so high at 50Hz, 100Hz and 1MHz, and whether the calibrator is wrong or the 7081? Oh dear, life was so much simpler when I only had one clock!!! Dave

JL

J. L. Trantham

Wed, Mar 21, 2012 12:42 AM

David,

As you said, to the man with one watch ...........

You need a reference. Which do you believe to be the best? Get it (or
more) calibrated. Aren't you near Ametek?

I have a 7081 and two 3458A's with all just back from calibration from their
respective companies. I now have three different answers.

The two 3458A's are in the midst of an experiment with programming and
therefore have not been in a 'controlled environment' at this time.
However, it seems to me that I am going to have to repeat the calibration
cycle in a year or so and see how the three compare after that.

I tend to believe the 7081 on the basis that I used it as a 'transfer'
standard' to 'home cal' one of the 3458A's. When the 3458A got back from
Agilent, it was within spec on all the ranges that I used the 7081 as the
'transfer standard'.

Good luck.

Joe

-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of David C. Partridge
Sent: Tuesday, March 20, 2012 10:48 AM
To: 'Discussion of precise voltage measurement'
Subject: [volt-nuts] Fluke 5200A AC Calibrator

I just recently managed to buy a spares unit for my 5200A.

I'm delighted to report that between the two units, and after a bit of
trouble de-soldering edge connectors, I now have a working, quiet (old fan
was DEAFENING), but uncalibrated AC calibrator.

Checking the output is against my 7081, here is what I'm see on the 1V range
set for 1V (the other ranges show a very similar pattern):

Frequency Reading Error
50Hz 1.00371 .371% <--- Surprisingly high
100Hz 1.00091 .091% <--- Surprisingly high
500Hz .99993 .007%
1kHz .99990 .010%
5kHz .99991 .009%
10kHz .99991 .009%
50kHz 1.00004 .004%
100kHz 1.00003 .003%
500kHz .99718 .282%
1MHz .98859 1.140% <--- This seems very high

Comparing the results against a 7150Plus which was connected in parallel, I
get a different story:

Frequency Reading Error
50Hz .99993 .007% *** see below
100Hz .99989 .011%
500Hz .99991 .009%
1kHz .99991 .009%
5kHz .99993 .007%
10kHz .99993 .007%
50kHz 1.00028 .028%
100kHz .99933 .077%

Substituting a 7151 for the 7150Plus I get:

Frequency Reading Error
50Hz .99986 .014% *** see below
100Hz .99992 .008%
500Hz .99997 .003%
1kHz .99997 .003%
5kHz .99997 .003%
10kHz .99995 .005%
50kHz 1.00002 .002%
100kHz .99895 .105%

These figures are quite impressive for the 7150Plus and the 7151 as the 24
hour figures for the 7150Plus are 40Hz-10kHz range are .03% + 15 counts and
the one year figures are .07% + 15 counts. The 7151 figures are similar.

(***) I was only able to get a stable reading at 50Hz by grounding the low
output of the calibrator. I'm not quite sure what the problem is here.

If I believe the 7150Plus or the 7151, the calibrator is correct within the
limits of the meters' accuracy.

If I believe the 7081, the calibrator is way off at the low end and high end
of the frequency ranges.

Hmmmm ...

Does anyone have any suggestions as to why the 7081 seems to read so high at
50Hz, 100Hz and 1MHz, and whether the calibrator is wrong or the 7081?

Oh dear, life was so much simpler when I only had one clock!!!

Dave

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David, As you said, to the man with one watch ........... You need a reference. Which do you believe to be the best? Get it (or more) calibrated. Aren't you near Ametek? I have a 7081 and two 3458A's with all just back from calibration from their respective companies. I now have three different answers. The two 3458A's are in the midst of an experiment with programming and therefore have not been in a 'controlled environment' at this time. However, it seems to me that I am going to have to repeat the calibration cycle in a year or so and see how the three compare after that. I tend to believe the 7081 on the basis that I used it as a 'transfer' standard' to 'home cal' one of the 3458A's. When the 3458A got back from Agilent, it was within spec on all the ranges that I used the 7081 as the 'transfer standard'. Good luck. Joe -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of David C. Partridge Sent: Tuesday, March 20, 2012 10:48 AM To: 'Discussion of precise voltage measurement' Subject: [volt-nuts] Fluke 5200A AC Calibrator I just recently managed to buy a spares unit for my 5200A. I'm delighted to report that between the two units, and after a bit of trouble de-soldering edge connectors, I now have a working, quiet (old fan was DEAFENING), but uncalibrated AC calibrator. Checking the output is against my 7081, here is what I'm see on the 1V range set for 1V (the other ranges show a very similar pattern): Frequency Reading Error 50Hz 1.00371 .371% <--- Surprisingly high 100Hz 1.00091 .091% <--- Surprisingly high 500Hz .99993 .007% 1kHz .99990 .010% 5kHz .99991 .009% 10kHz .99991 .009% 50kHz 1.00004 .004% 100kHz 1.00003 .003% 500kHz .99718 .282% 1MHz .98859 1.140% <--- This seems very high Comparing the results against a 7150Plus which was connected in parallel, I get a different story: Frequency Reading Error 50Hz .99993 .007% *** see below 100Hz .99989 .011% 500Hz .99991 .009% 1kHz .99991 .009% 5kHz .99993 .007% 10kHz .99993 .007% 50kHz 1.00028 .028% 100kHz .99933 .077% Substituting a 7151 for the 7150Plus I get: Frequency Reading Error 50Hz .99986 .014% *** see below 100Hz .99992 .008% 500Hz .99997 .003% 1kHz .99997 .003% 5kHz .99997 .003% 10kHz .99995 .005% 50kHz 1.00002 .002% 100kHz .99895 .105% These figures are quite impressive for the 7150Plus and the 7151 as the 24 hour figures for the 7150Plus are 40Hz-10kHz range are .03% + 15 counts and the one year figures are .07% + 15 counts. The 7151 figures are similar. (***) I was only able to get a stable reading at 50Hz by grounding the low output of the calibrator. I'm not quite sure what the problem is here. If I believe the 7150Plus or the 7151, the calibrator is correct within the limits of the meters' accuracy. If I believe the 7081, the calibrator is way off at the low end and high end of the frequency ranges. Hmmmm ... Does anyone have any suggestions as to why the 7081 seems to read so high at 50Hz, 100Hz and 1MHz, and whether the calibrator is wrong or the 7081? Oh dear, life was so much simpler when I only had one clock!!! 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.

DC

David C. Partridge

Wed, Mar 21, 2012 2:59 AM

Replying to my own post - but I do have highly pertinent information:

I received an email from a person I know at Ametek:

As for the lower frequencies, did you try using the AC filter button?
I tried my (annually calibrated) 7081 on a Fluke 5720A before leaving
work and at 50Hz I got virtually the same reading as you, 1.00367.
Selecting the AC filter gave a much improved reading of 1.00002.
I haven't got the operating manual to hand but I seem to remember it
recommending using the filter at 50Hz and below.

He was pretty much on the mark, though the manual recommends the filter
be used below 1kHz!

With AC filter engaged:

Frequency Reading Error
50Hz 0.999996 .0004%
100Hz 0.999868 .0132% <--- A little high but not bad

The 500kHz and 1MHz figures are also within specification for the 7081

Cheers
Dave
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of David C. Partridge
Sent: 20 March 2012 15:48
To: 'Discussion of precise voltage measurement'
Subject: [volt-nuts] Fluke 5200A AC Calibrator

Checking the output is against my 7081, here is what I'm see on the 1V range set for 1V (the other ranges show a very similar pattern):

Frequency Reading Error
50Hz 1.00371 .371% <--- Surprisingly high
100Hz 1.00091 .091% <--- Surprisingly high

Replying to my own post - but I do have highly pertinent information: I received an email from a person I know at Ametek: >As for the lower frequencies, did you try using the AC filter button? >I tried my (annually calibrated) 7081 on a Fluke 5720A before leaving >work and at 50Hz I got virtually the same reading as you, 1.00367. >Selecting the AC filter gave a much improved reading of 1.00002. >I haven't got the operating manual to hand but I seem to remember it >recommending using the filter at 50Hz and below. He was pretty much on the mark, though the manual recommends the filter be used below 1kHz! With AC filter engaged: Frequency Reading Error 50Hz 0.999996 .0004% 100Hz 0.999868 .0132% <--- A little high but not bad The 500kHz and 1MHz figures are also within specification for the 7081 Cheers Dave -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of David C. Partridge Sent: 20 March 2012 15:48 To: 'Discussion of precise voltage measurement' Subject: [volt-nuts] Fluke 5200A AC Calibrator Checking the output is against my 7081, here is what I'm see on the 1V range set for 1V (the other ranges show a very similar pattern): Frequency Reading Error 50Hz 1.00371 .371% <--- Surprisingly high 100Hz 1.00091 .091% <--- Surprisingly high

CH

Chuck Harris

Wed, Mar 21, 2012 12:21 PM

Being as you are in the UK, land of 50Hz power mains, any false indications
on 50 Hz would likely be the result of ground loops, or coupling (inductive
or capacitive) from things hooked to your power mains, and 100Hz the result
of ripple on power supplies.

Have you checked the filter caps on all of the affected instruments?

-Chuck Harris

David C. Partridge wrote:

Replying to my own post - but I do have highly pertinent information:

I received an email from a person I know at Ametek:

As for the lower frequencies, did you try using the AC filter button?
I tried my (annually calibrated) 7081 on a Fluke 5720A before leaving
work and at 50Hz I got virtually the same reading as you, 1.00367.
Selecting the AC filter gave a much improved reading of 1.00002.
I haven't got the operating manual to hand but I seem to remember it
recommending using the filter at 50Hz and below.

He was pretty much on the mark, though the manual recommends the filter
be used below 1kHz!

With AC filter engaged:

Frequency Reading Error
50Hz 0.999996 .0004%
100Hz 0.999868 .0132%<--- A little high but not bad

Being as you are in the UK, land of 50Hz power mains, any false indications on 50 Hz would likely be the result of ground loops, or coupling (inductive or capacitive) from things hooked to your power mains, and 100Hz the result of ripple on power supplies. Have you checked the filter caps on all of the affected instruments? -Chuck Harris David C. Partridge wrote: > Replying to my own post - but I do have highly pertinent information: > > I received an email from a person I know at Ametek: > >> As for the lower frequencies, did you try using the AC filter button? >> I tried my (annually calibrated) 7081 on a Fluke 5720A before leaving >> work and at 50Hz I got virtually the same reading as you, 1.00367. >> Selecting the AC filter gave a much improved reading of 1.00002. >> I haven't got the operating manual to hand but I seem to remember it >> recommending using the filter at 50Hz and below. > > He was pretty much on the mark, though the manual recommends the filter > be used below 1kHz! > > With AC filter engaged: > > Frequency Reading Error > 50Hz 0.999996 .0004% > 100Hz 0.999868 .0132%<--- A little high but not bad

DC

David C. Partridge

Wed, Mar 21, 2012 12:34 PM

Chuck

Filter caps on the 5200A are yet to be checked.

Dave

Chuck Filter caps on the 5200A are yet to be checked. Dave

RA

Robert Atkinson

Wed, Mar 21, 2012 5:49 PM

Hi David,
Some meters have specific sample rates to help null mains noise. Often they are link / switch selectable for 50 / 60 Hz mains. Might be worth checking this in the Solartron manual.

Robert G8RPI.

From: David C. Partridge david.partridge@perdrix.co.uk
To: 'Discussion of precise voltage measurement' volt-nuts@febo.com
Sent: Wednesday, 21 March 2012, 12:34
Subject: Re: [volt-nuts] Fluke 5200A AC Calibrator

Chuck

Filter caps on the 5200A are yet to be checked.

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.

Hi David, Some meters have specific sample rates to help null mains noise. Often they are link / switch selectable for 50 / 60 Hz mains. Might be worth checking this in the Solartron manual. Robert G8RPI. ________________________________ From: David C. Partridge <david.partridge@perdrix.co.uk> To: 'Discussion of precise voltage measurement' <volt-nuts@febo.com> Sent: Wednesday, 21 March 2012, 12:34 Subject: Re: [volt-nuts] Fluke 5200A AC Calibrator Chuck Filter caps on the 5200A are yet to be checked. 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.

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Fluke 5200A AC Calibrator