Fluke 335A
My 335A is, seemingly, behaving but I have noticed two issues.
First, there is a slow fluctuation in the 'zero' reading and requires
adjustment every day or so to make it read 0.00000+/-.
Second, once adjusted, when set to 0.123456 volts, it fluctuates 2 or 3 uV
when monitored on an HP 3478A.
Are these behaviors normal? If not, what suggestions are there to resolve
this?
Thanks in advance.
Joe
Hi Joe,
On a given range, the 335D's noise is a fixed quantity regardless of your
output voltage setting. Therefore as a percentage of output voltage, the
noise is the least at full scale of range, and greatest at voltage settings
that are a small percentage of full-scale.
Unfortunately the lowest output range for the 335D is 10VDC. Therefore for
most quiet output, you'd have to set for something near 10VDC (full-scale).
As a percentage of output voltage setting, noise and zero-offsets will be
higher at tenth scale. In your case you're setting for approximately
hundredth scale. So noise and zero offset will be significant as a
percentage of your output voltage setting.
One way around this problem would be to build an external divide by 10 and
divide by 100 resistive divider. That way you could set the 335D to near
full-scale, yet achieve the lower voltages you desire.
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: volt-nuts@febo.com
Sent: Monday, September 26, 2011 7:28 PM
Subject: [volt-nuts] Fluke 335A
My 335A is, seemingly, behaving but I have noticed two issues.
First, there is a slow fluctuation in the 'zero' reading and requires
adjustment every day or so to make it read 0.00000+/-.
Second, once adjusted, when set to 0.123456 volts, it fluctuates 2 or 3 uV
when monitored on an HP 3478A.
Are these behaviors normal? If not, what suggestions are there to resolve
this?
Thanks in advance.
Joe
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https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.
Greg,
If I understand the spec's correctly, the accuracy at 10.000000 Volts is +/-
30 uV (+/- (0.002% of setting + 10 uV)). At 0.123456 Volts, it would be +/-
12.5 uV. The stability spec is +/-(0.001% of setting + 10 uV) per month or
11.23456 uV. I think I am within those specs.
However, I did not see a 'noise' spec.
The question is how stable should the reading be when watching it on a DMM?
Mine fluctuates about 3 uV over about 2 seconds (on an HP 3478A at nominal
settings). Is that normal? I am hoping someone with a 335A or D will be
able to look at theirs and tell me if what I am seeing is reasonable or do I
have more work to do to obtain better stability/lower noise.
It ultimately boils down to what to trust, the meter or the standard. You
know the old saying, 'a man with one volt meter......'.
Thanks,
Joe
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of gbusg
Sent: Monday, September 26, 2011 8:56 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 335A
Hi Joe,
On a given range, the 335D's noise is a fixed quantity regardless of your
output voltage setting. Therefore as a percentage of output voltage, the
noise is the least at full scale of range, and greatest at voltage settings
that are a small percentage of full-scale.
Unfortunately the lowest output range for the 335D is 10VDC. Therefore for
most quiet output, you'd have to set for something near 10VDC (full-scale).
As a percentage of output voltage setting, noise and zero-offsets will be
higher at tenth scale. In your case you're setting for approximately
hundredth scale. So noise and zero offset will be significant as a
percentage of your output voltage setting.
One way around this problem would be to build an external divide by 10 and
divide by 100 resistive divider. That way you could set the 335D to near
full-scale, yet achieve the lower voltages you desire.
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: volt-nuts@febo.com
Sent: Monday, September 26, 2011 7:28 PM
Subject: [volt-nuts] Fluke 335A
My 335A is, seemingly, behaving but I have noticed two issues.
First, there is a slow fluctuation in the 'zero' reading and requires
adjustment every day or so to make it read 0.00000+/-.
Second, once adjusted, when set to 0.123456 volts, it fluctuates 2 or 3 uV
when monitored on an HP 3478A.
Are these behaviors normal? If not, what suggestions are there to resolve
this?
Thanks in advance.
Joe
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
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and follow the instructions there.
Hi Joe,
My calculations agree with yours, as far as Fluke specs for your two
voltages are concerned.
Fluke spec'd Ripple and Noise (all frequencies) as <20 uV rms on the 10V
range. So that would be another 2ppm rms adder for 10Vdc setting, 20ppm rms
adder for 1Vdc setting and 200ppm rms adder for 100mVdc setting. But I'm not
immediately sure how that rms noise spec might translate to observed
racking-around on your 3478A (depending on integration time setting on your
3478A, etc.).
Fluke's basic 10 uV adder (for 10Vdc range) translates to 1ppm adder at
10Vdc setting, 10ppm adder at 1Vdc setting and 100ppm adder at 100mVdc
setting. The way I look at it, that 10 uV adder accounts for some short-term
instability (which might also show up as some racking around on your 3478A)
plus DC zero offset (as observed on your 3478A).
Anyway, obviously the 335D "likes" full (or near full) scale the best.
You could test your 3478A short-term noise (racking around of readings) by
using it to read a source that's known to be very quiet. Or at least you
could build a 10 to 1 or 100 to 1 resistive divider between 335D and your
3478A to see if that reduces the observed noise.
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 8:39 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
If I understand the spec's correctly, the accuracy at 10.000000 Volts is +/-
30 uV (+/- (0.002% of setting + 10 uV)). At 0.123456 Volts, it would be +/-
12.5 uV. The stability spec is +/-(0.001% of setting + 10 uV) per month or
11.23456 uV. I think I am within those specs.
However, I did not see a 'noise' spec.
The question is how stable should the reading be when watching it on a DMM?
Mine fluctuates about 3 uV over about 2 seconds (on an HP 3478A at nominal
settings). Is that normal? I am hoping someone with a 335A or D will be
able to look at theirs and tell me if what I am seeing is reasonable or do I
have more work to do to obtain better stability/lower noise.
It ultimately boils down to what to trust, the meter or the standard. You
know the old saying, 'a man with one volt meter......'.
Thanks,
Joe
Greg,
Are there sources 'known to be quite'? Any way to make them quite?
How about a standard D cell battery? With a filter capacitor? I suspect it
will have a slow downward trend but how about ripple and noise?
Do any of the 'volt-nuts' have a favorite source to measure when looking to
see how 'stable' their DMM is?
I'll have to go back and look at the manual for the 335A about the Ripple
and Noise spec.
Thanks,
Joe
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of gbusg
Sent: Monday, September 26, 2011 10:05 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 335A
Hi Joe,
My calculations agree with yours, as far as Fluke specs for your two
voltages are concerned.
Fluke spec'd Ripple and Noise (all frequencies) as <20 uV rms on the 10V
range. So that would be another 2ppm rms adder for 10Vdc setting, 20ppm rms
adder for 1Vdc setting and 200ppm rms adder for 100mVdc setting. But I'm not
immediately sure how that rms noise spec might translate to observed
racking-around on your 3478A (depending on integration time setting on your
3478A, etc.).
Fluke's basic 10 uV adder (for 10Vdc range) translates to 1ppm adder at
10Vdc setting, 10ppm adder at 1Vdc setting and 100ppm adder at 100mVdc
setting. The way I look at it, that 10 uV adder accounts for some short-term
instability (which might also show up as some racking around on your 3478A)
plus DC zero offset (as observed on your 3478A).
Anyway, obviously the 335D "likes" full (or near full) scale the best.
You could test your 3478A short-term noise (racking around of readings) by
using it to read a source that's known to be very quiet. Or at least you
could build a 10 to 1 or 100 to 1 resistive divider between 335D and your
3478A to see if that reduces the observed noise.
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 8:39 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
If I understand the spec's correctly, the accuracy at 10.000000 Volts is +/-
30 uV (+/- (0.002% of setting + 10 uV)). At 0.123456 Volts, it would be +/-
12.5 uV. The stability spec is +/-(0.001% of setting + 10 uV) per month or
11.23456 uV. I think I am within those specs.
However, I did not see a 'noise' spec.
The question is how stable should the reading be when watching it on a DMM?
Mine fluctuates about 3 uV over about 2 seconds (on an HP 3478A at nominal
settings). Is that normal? I am hoping someone with a 335A or D will be
able to look at theirs and tell me if what I am seeing is reasonable or do I
have more work to do to obtain better stability/lower noise.
It ultimately boils down to what to trust, the meter or the standard. You
know the old saying, 'a man with one volt meter......'.
Thanks,
Joe
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 Joe,
The Fluke 732A (at 10Vdc) is by far the most "quiet" source I have here.
With HP 3458A integration time set for 100 Power Line Cycles, (and for the
combination of [Noise Produced by 732A]+[Noise Induced by 3458A]), I'm
observing +/- 0.03ppm short-term noise (racking-around of the 3458A from
reading to reading) at 10Vdc.
Regarding short-term noise of other possible DCV sources and combinations
(including your D cell battery suggestion, homebrew zener references, etc.),
I defer to the expertise and experience of the other fellows in the group,
for their comments. (Fellows, what say regarding Joe's question?)
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 9:14 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
Are there sources 'known to be quite'? Any way to make them quite?
How about a standard D cell battery? With a filter capacitor? I suspect it
will have a slow downward trend but how about ripple and noise?
Do any of the 'volt-nuts' have a favorite source to measure when looking to
see how 'stable' their DMM is?
I'll have to go back and look at the manual for the 335A about the Ripple
and Noise spec.
Thanks,
Joe
Greg,
If my math is correct, then you see about +/- 0.3 uV at 10 V. Correct?
Joe
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of gbusg
Sent: Monday, September 26, 2011 10:45 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 335A
Hi Joe,
The Fluke 732A (at 10Vdc) is by far the most "quiet" source I have here.
With HP 3458A integration time set for 100 Power Line Cycles, (and for the
combination of [Noise Produced by 732A]+[Noise Induced by 3458A]), I'm
observing +/- 0.03ppm short-term noise (racking-around of the 3458A from
reading to reading) at 10Vdc.
Regarding short-term noise of other possible DCV sources and combinations
(including your D cell battery suggestion, homebrew zener references, etc.),
I defer to the expertise and experience of the other fellows in the group,
for their comments. (Fellows, what say regarding Joe's question?)
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 9:14 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
Are there sources 'known to be quite'? Any way to make them quite?
How about a standard D cell battery? With a filter capacitor? I suspect it
will have a slow downward trend but how about ripple and noise?
Do any of the 'volt-nuts' have a favorite source to measure when looking to
see how 'stable' their DMM is?
I'll have to go back and look at the manual for the 335A about the Ripple
and Noise spec.
Thanks,
Joe
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 Joe,
Yes, that's correct.
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 10:12 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
If my math is correct, then you see about +/- 0.3 uV at 10 V. Correct?
Joe
-----Original Message-----
From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On
Behalf Of gbusg
Sent: Monday, September 26, 2011 10:45 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Fluke 335A
Hi Joe,
The Fluke 732A (at 10Vdc) is by far the most "quiet" source I have here.
With HP 3458A integration time set for 100 Power Line Cycles, (and for the
combination of [Noise Produced by 732A]+[Noise Induced by 3458A]), I'm
observing +/- 0.03ppm short-term noise (racking-around of the 3458A from
reading to reading) at 10Vdc.
Regarding short-term noise of other possible DCV sources and combinations
(including your D cell battery suggestion, homebrew zener references, etc.),
I defer to the expertise and experience of the other fellows in the group,
for their comments. (Fellows, what say regarding Joe's question?)
Best,
Greg
I measured a 731 with a scope to see the noise. It was around 25 uVpp. I think that is the most easy way. You see how much disconnected and how much it s connected. I úse a tektronix 547 with E-plugin for this. ( a lot cheaper then a 7,5 digit or more multimeter ;-)
Fred PA4TIM
Op 27 sep. 2011 om 05:04 heeft "gbusg" gbusg@comcast.net het volgende geschreven:
Hi Joe,
My calculations agree with yours, as far as Fluke specs for your two
voltages are concerned.
Fluke spec'd Ripple and Noise (all frequencies) as <20 uV rms on the 10V
range. So that would be another 2ppm rms adder for 10Vdc setting, 20ppm rms
adder for 1Vdc setting and 200ppm rms adder for 100mVdc setting. But I'm not
immediately sure how that rms noise spec might translate to observed
racking-around on your 3478A (depending on integration time setting on your
3478A, etc.).
Fluke's basic 10 uV adder (for 10Vdc range) translates to 1ppm adder at
10Vdc setting, 10ppm adder at 1Vdc setting and 100ppm adder at 100mVdc
setting. The way I look at it, that 10 uV adder accounts for some short-term
instability (which might also show up as some racking around on your 3478A)
plus DC zero offset (as observed on your 3478A).
Anyway, obviously the 335D "likes" full (or near full) scale the best.
You could test your 3478A short-term noise (racking around of readings) by
using it to read a source that's known to be very quiet. Or at least you
could build a 10 to 1 or 100 to 1 resistive divider between 335D and your
3478A to see if that reduces the observed noise.
Best,
Greg
----- Original Message -----
From: "J. L. Trantham" jltran@att.net
To: "'Discussion of precise voltage measurement'" volt-nuts@febo.com
Sent: Monday, September 26, 2011 8:39 PM
Subject: Re: [volt-nuts] Fluke 335A
Greg,
If I understand the spec's correctly, the accuracy at 10.000000 Volts is +/-
30 uV (+/- (0.002% of setting + 10 uV)). At 0.123456 Volts, it would be +/-
12.5 uV. The stability spec is +/-(0.001% of setting + 10 uV) per month or
11.23456 uV. I think I am within those specs.
However, I did not see a 'noise' spec.
The question is how stable should the reading be when watching it on a DMM?
Mine fluctuates about 3 uV over about 2 seconds (on an HP 3478A at nominal
settings). Is that normal? I am hoping someone with a 335A or D will be
able to look at theirs and tell me if what I am seeing is reasonable or do I
have more work to do to obtain better stability/lower noise.
It ultimately boils down to what to trust, the meter or the standard. You
know the old saying, 'a man with one volt meter......'.
Thanks,
Joe
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.