[volt-nuts] volt-nuts Digest, Vol 55, Issue 7 standards calibration with multiple units
new
pitts7 at williams-net.com
Sun Mar 9 01:18:55 EST 2014
Greetings from Ohio...
I was told that the uncertainty goes down with the square root...?
That would mean 4 standards averaged together would cut the error in half...
And 9 would cut it to one third.
Is this correct? If not, what is the formula?
Willy
ps. I am reviving a 732b I bought on fleabay!
----- Original Message -----
From: <volt-nuts-request at febo.com>
To: <volt-nuts at febo.com>
Sent: Saturday, March 08, 2014 11:58 PM
Subject: volt-nuts Digest, Vol 55, Issue 7
> Send volt-nuts mailing list submissions to
> volt-nuts at 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 at febo.com
>
> You can reach the person managing the list at
> volt-nuts-owner at 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: Economical Standard Calibration (Dallas Smith)
> 2. Re: volt-nuts Digest, Vol 55, Issue 6 (Michael Hong)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 8 Mar 2014 22:30:40 -0500
> From: Dallas Smith <dosmith at outlook.com>
> To: Bob Albert <bob91343 at yahoo.com>, Discussion of precise voltage
> measurement <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] Economical Standard Calibration
> Message-ID: <BLU0-SMTP114433102E012135419785EBC750 at phx.gbl>
> Content-Type: text/plain; charset="UTF-8"; format=flowed
>
> Hi Bob,
>
> I also heard about this technique, probably on 'volt-nuts'. They
> connected 16 LM199's summed
> together isolated with about 500 ohms each. This averaged the voltage
> and reduced the noise.
>
> But not knowing the absolute voltage will not calibrated my Fluke 731b.
> It appears if I want
> a calibration, I'll have to play with the big boys and spend the bucks.
>
> Dallas
>
>
> On 3/8/2014 10:05 PM, Bob Albert wrote:
>> I have five AD587 switch selected, powered by a wall wart. They seem to
>> be very good, but of course not in the league of the units discussed
>> here.
>>
>> In any case, they are 10V and all within about a millivolt. If I average
>> them I should get a statistically valid accuracy improvement, neglecting
>> any systematic errors in their manufacture.
>>
>>
>> While watching the display on my HP 3456A I begin to realize that my need
>> for 'exact' voltage isn't really so great. Certainly what I have is more
>> accurate than anything I will ever really need. But it's fun to see the
>> variation and watch the drift and compare my other high class voltmeters.
>> The 3456A manual says to wait an hour for it to warm up and that seems
>> reasonable; nearly all the drift is gone by about 45 minutes.
>>
>> Bob
>>
>>
>>
>>
>> On Saturday, March 8, 2014 5:34 PM, Dallas Smith <dosmith at outlook.com>
>> wrote:
>>
>> I'm in west Michigan, Holland. As far as accuracy the manual states
>> ?10ppm for 30 day or ?30ppm per year for the 10v output .
>> I need it to calibrate my (modified with reference oven) EDC (Electronic
>> Development Corp.) model 520a. Which I calibrate my Fluke 510a with a
>> Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my
>> audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data
>> Precision Model 2500.
>>
>> So if I can achieve ?50ppm per year this would be sufficient, but better
>> would be nice since they may not be calibrated every year.
>>
>> I?m just a hobbies audio engineer that designs audiophile equipment and
>> other interesting projects not related. So sending it to fluke is not
>> economical for me.
>>
>> Since Joe suspended operations for his SVR-T with low cost calibration.
>> I purchased one and put it in a 35?C oven and it seems to outperform the
>> Fluke 731b as compared to my 8505 for drift. I will have three 10 volt
>> references in my lab to track uncertainty.
>>
>> So are there any calibration labs that will calibrate my 731a and my home
>> brew reference?s?
>>
>>
>>
>>
>>> Date: Sat, 8 Mar 2014 16:00:41 -0700
>>> From: nova at npgcable.com
>>> To: volt-nuts at febo.com
>>> Subject: Re: [volt-nuts] Economical Standard Calibration
>>>
>>> Dallas,
>>>
>>> How accurately do you need the 731B set?
>>>
>>> Where are you located? I am in Flagstaff, Arizona
>>>
>>> I have four 731s, and I know how to calibrate them.
>>>
>>> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration
>>> soon. I
>>> do not know the turnaround time.
>>>
>>> Joe
>>>
>>>
>>>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 8 Mar 2014 20:55:42 -0800 (PST)
> From: Michael Hong <mikeyahee at yahoo.com>
> To: "volt-nuts at febo.com" <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] volt-nuts Digest, Vol 55, Issue 6
> Message-ID:
> <1394340942.13755.YahooMailNeo at web141606.mail.bf1.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Bill:
> Thank you for the detailed info.
>
> Since my stroke and depression at my early 50's, my language ability
> changed a lot. Writing, talking and typing, too. But getting better. So
> lots of people ask
> me the same question. I live in Cypress, Orange County, California. Within
> a few miles of me, there a lots of high tech companies , like Boeing.
>
> The seller's DMM needs to be calibrated or better yet to be repaired.
> I have many 6 1/2 digit and 7 1/2 digit DMMs. Two of them NIST caled by
> locals. All measure the 732A high and out of ranges. But always 10V and 1V
> are within 5ppm and 1.018V is within 30ppm of 10V and 5V.
> Look at the seller DMM reading 10V : +40ppm 1V: -20ppm and 1.018V range
> show -50ppm.
>
> To make more accurate assessment of this 732A's output, It needs to be
> compared to another Zener or accurate 3458A.
> Once it is found out of cal ranges, I will return it or sell it to
> whomever wants it at my cost and understand no battery and has to be
> fixed.
>
> I talked to most if not all cal labs around me. Most of them are poor.
> They are closing the business or are struggling to maintain their business
> as is. I heard two labs are selling their equipments. They can't afford to
> own and calibrated 732A/B, ESI SR104, L&N Thomas one. They can't afford
> Agilent's Loveland 3458A calibration. Most of the lab owner can't afford
> one employee. They are doing the lab as part time job.
>
> I think the closest and affordable JJA services are Fluke(WA) and
> Agilent(CO). All others are government or military labs. Sandra is very
> expensive by hearsay.
>
> Is there any 'nut' 100 miles from me with reasonably accurate 3458A or
> 732A/B? I like to take my either 3457A, Gell-Lab SVR-T, or 732A to you to
> compare with yours. All I need is within +-5ppm from JJA. New 34461 can be
> a good comparable too. Any 6 1/2 or 7 1/2 digits calibrated by either
> Agilent or Fluke will be good, too.
>
> Until then everything is wild guess, I think, sorry. Anybody willing to
> give me the help with these equipments send me an email. I will be deeply
> appreciated.
>
>
> Thank you all.
>
> Best Regards,
>
>
>
>
> On Saturday, March 8, 2014 7:05 PM, "volt-nuts-request at febo.com"
> <volt-nuts-request at febo.com> wrote:
>
> Send volt-nuts mailing list submissions to
> ??? volt-nuts at 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 at febo.com
>
> You can reach the person managing the list at
> ??? volt-nuts-owner at 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: A Fluke 732A: Return it or keep it? (Bill Gold)
> ? 2. Re: A Fluke 732A (Richard Moore)
> ? 3. Re: Economical Standard Calibration (Dallas Smith)
> ? 4. Re: A Fluke 732A: Return it or keep it? (Tom Knox)
> ? 5. Re: Economical Standard Calibration (Bob Albert)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 8 Mar 2014 16:21:36 -0800
> From: "Bill Gold" <wpgold3637 at att.net>
> To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
> Message-ID: <006a01cf3b2d$88a6e5c0$b7f95c47 at home>
> Content-Type: text/plain;??? charset="iso-8859-1"
>
> Michael,
>
> Just a side note here on adjusting the 3 calibration pots inside the front
> panel of the 732A
>
> Fluke did supply an adjustment tool with each 732A but I don't know
> exactly
> who made it or what model number.? I use a General Cement ( GC ) model
> 8276
> adjustment tool, the end with the blade recessed, to do the job.?
> Sometimes
> it takes a little fiddling and patience to get the adjustment tool to
> engage
> the slot in the pot, but it can be done and without any danger of shorting
> something out.
> http://www.alliedelec.com/search/productdetail.aspx?SKU=70159521
>
> 360 uvolts ( 36 ppm ) above 10 volts seems more than a little high for one
> of these units.? The worst I have seen over 6 units is around 120 uvolts (
> 12 ppm ) out of spec, but I was able to bring it in by changing the
> jumpers
> on the A7 board.? It is conceivable that someone totally screwed up the
> last
> calibration.? You would need to take off the top cover, the top guard
> cover,
> remove the top foam piece and take a look at the jumpers on the A7 board.
> The one thing I can't remember right now is if shorting the resistors R12
> through R17 on the A5 board, by adding or removing jumpers on the A7 board
> lowers or raises the output voltage at 10 volts.? But in the manual I did
> find an addendum to paragraph 4-38 which says.
>
> "Cutting a jumper increases the 732A 10 V output the amount labeled above
> the jumper.? Likewise, completing a jumper decreases the output the amount
> of the jumper label".
>
> So that should help you once you view the jumpers on the A7 board.? I do
> know that you can add or remove multiple jumpers on the A7 board so the
> total range of the change in the 10 V output can be around 750 uvolts ( 75
> ppm ).? If you see many jumpers on the A7 board this would mean that
> someone
> tried to lower the output voltage and that the reference could not be
> adjusted properly to exactly 10 V.? In other words if you see no jumpers
> on
> the A7 board then you could possibly bring the output to exactly 10 V from
> it's present ( presumed ) 36 ppm too high.? You really need a "standard"
> 10
> volts before you do this.? But since the seller's DVM is reading 40 ppm
> too
> high and your 3457A is reading 36 ppm too high then the output of the 732A
> is probably also high.
>
> What part of the country are you located in?? Maybe one of the many "Volt
> Nuts" lives close to you can give you an idea of what 10 Volts really is.
>
> Also I have seen batteries that are so old and messed up that the
> "Charging"
> light will never come on.? The internal resistance is so high that the
> charging circuit simply doesn't work.? Your thermistor value and stability
> seems very good so it looks like the oven temperature control circuits are
> working correctly.
>
> I hope the above helps you in determining if you keep the unit or send it
> back.
>
> Bill
>
> ----- Original Message -----
> From: "J. L. Trantham" <jltran at att.net>
> To: "'Michael Hong'" <mikeyahee at yahoo.com>; "'Discussion of precise
> voltage
> measurement'" <volt-nuts at febo.com>
> Sent: Friday, March 07, 2014 5:57 PM
> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>
>
> Michael,
>
>
> The schematic of the A5 Reference PCB Assembly shows the calibration
> adjustments and the drawing of that assembly shows the location of the
> adjustments.? They are deep inside the unit.? You'll need a small flat
> bladed tool, a flashlight, and probably a magnifier.? I used a length of
> 12
> ga. copper wire with one end flattened to make a screwdriver.
>
> Good luck.
>
> Joe
>
> -----Original Message-----
> From: volt-nuts-bounces at febo.com [mailto:volt-nuts-bounces at febo.com] On
> Behalf Of Michael Hong
> Sent: Friday, March 07, 2014 6:19 PM
> To: volt-nuts at febo.com
> Subject: [volt-nuts] A Fluke 732A: Return it or keep it?
>
>
> (3)
> Front panel calibration hole
> I put a thin flat blade driver into the holes. I couldn't feel anything
> until 4 1/4" inside where I felt something but not the potentiometer.
>
>
>
> 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
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
> and follow the instructions there.
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 08 Mar 2014 17:17:53 -0800
> From: Richard Moore <richiem5683 at gmail.com>
> To: volt-nuts at febo.com
> Subject: Re: [volt-nuts] A Fluke 732A
> Message-ID: <531BC141.50406 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Back to a few of the original issues. A big questionh would be just how
> accurate the average volt nut needs the 732A to be? I once owned two
> 732A, one working normally, and kept hot 24/7, and one that needed some
> work with the charging circuits and new batteries. My 3458A being newly
> cal'd at Agilent in Colorado Springs, I matched the two 732As to the
> 3458A, then powered off the one with problems, worked on it off and on
> over several weeks, then powered it back up. What I found was that the
> one I worked on (after 48 hours warm-up) was within 0.2ppm of the hot
> one and the 3458A. Over the next year, the drift got a little larger
> among the three, but not by much -- a spread of about another 0.2ppm if
> I remember right.
>
> That's when I decided that since I wasn't going to try to be a standards
> lab, shipping a 732A cold for cal was much easier and effective than
> trying to do it hot, and I live about 30 air miles from Fluke in Everett.
>
> Can you live with 1ppm uncertainty in your 732A? Some here obviously
> can't, but I think many of us can and would be happy with that level of
> accuracy -- certainly good enough to cal the various 6-1/2 digit meters
> around, including the 3457 mentioned originally. And given my experience
> of 732A stability, especially the good old ones that come on ebay and
> the like, that 1ppm uncertainty is also a good check on the state of cal
> of even the 8-1/2 digit boxes, which despite their resolution, are not
> spec'd long-term for even 1ppm at 10V.
>
> Best,
> Dick Moore
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 8 Mar 2014 20:26:23 -0500
> From: Dallas Smith <dosmith at outlook.com>
> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] Economical Standard Calibration
> Message-ID: <BLU173-W61A13B82F3EDB51DFC82FBC750 at phx.gbl>
> Content-Type: text/plain; charset="Windows-1252"
>
> I'm in west Michigan, Holland. As far as accuracy the manual states?
> ?10ppm for 30 day or ?30ppm per year for the 10v output .
> I need it to calibrate my (modified with reference oven)? EDC (Electronic
> Development Corp.) model 520a. Which I calibrate my Fluke 510a with a
> Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my
> audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data
> Precision Model 2500.
>
> So if I can achieve ?50ppm per year this would be sufficient, but better
> would be nice since they may not be calibrated every year.
>
> I?m just a hobbies audio engineer that designs audiophile equipment and
> other interesting projects not related. So sending it to fluke is not
> economical for me.
>
> Since Joe suspended? operations for his SVR-T with low cost calibration. I
> purchased one and put it in a 35?C oven and it seems to outperform the
> Fluke 731b as compared to my 8505 for drift. I will have three 10 volt
> references in my lab to track uncertainty.
>
> So are there any calibration labs that will calibrate my 731a and my home
> brew reference?s?
>
>
>
>
>> Date: Sat, 8 Mar 2014 16:00:41 -0700
>> From: nova at npgcable.com
>> To: volt-nuts at febo.com
>> Subject: Re: [volt-nuts] Economical Standard Calibration
>>
>> Dallas,
>>
>> How accurately do you need the 731B set?
>>
>> Where are you located? I am in Flagstaff, Arizona
>>
>> I have four 731s, and I know how to calibrate them.
>>
>> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration
>> soon. I
>> do not know the turnaround time.
>>
>> Joe
>>
>>
>> On 3/8/2014 3:13 PM, Dallas Smith wrote:
>> > Good point, not a meter a Fluke 731b transfer standard. no access to
>> > local labs.
>> >
>> > On 3/8/2014 4:54 PM, Dr. David Kirkby wrote:
>> >> On 8 March 2014 21:44, Dallas Smith <dosmith at outlook.com> wrote:
>> >>> Hi nuts,
>> >>> This is my first post. The knowledge from contributors is amazing.
>> >>>
>> >>> Was wondering where one could economically get our_voltage standards
>> >>> calibrated_
>> >>> to some traceable standard since Joe Gellar suspended operations for
>> >>> his
>> >>> SVR-T?
>> >>>
>> >>> voltagestandard.com doesn't sell a 10v references and two of his 5v
>> >>> Vref5-002 are costly.
>> >>>
>> >>> Dallas
>> >> It would be worth stating what meter you have. Clearly what is going
>> >> to be useful for a 3.5 digit meter, will not be for an 8.5 digit 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.
> ??? ??? ??? ? ??? ??? ?
>
> ------------------------------
>
> Message: 4
> Date: Sat, 8 Mar 2014 19:01:26 -0600
> From: Tom Knox <actast at hotmail.com>
> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
> Message-ID: <COL130-W650C73854F0640689BDFCADF750 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
> I think everyone missed my point, Replace the current battery with ANY
> other type battery that is not destroyed by deep cyclng. Perhaps Ni-Mh
> would be better. Ni-Mh also has a very consistent output voltage (Low
> voltage drop) until nearly discharged. Also a quick Google search found a
> wealth of information on shipping Li-Ion and it appears the 732A batteries
> are right on the edge of no shipping restriction.
>
> Thomas Knox
>
>
>
>> Date: Sat, 8 Mar 2014 23:56:19 +0000
>> From: vnuts at toneh.demon.co.uk
>> To: volt-nuts at febo.com
>> Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>>
>> Unfortunately the hazards are indeed very real. The regulations were
>> almost certainly introduced because a UPS cargo plane crashed in Dubai
>> in 2010, killing both crew, as a result of a catastrophic fire in the
>> cargo of 80,000 to 90,000 lithium batteries.
>>
>> http://online.wsj.com/news/articles/SB10001424127887324110404578625801602671408
>>
>> And surprise, surprise:
>>
>> 'It added that shippers of some of the lithium battery cargo loaded onto
>> the plane in Hong Kong "did not properly declare these shipments" and
>> did not provide battery test reports recommended under U.N. aviation
>> guidelines.'
>>
>> (Which may be of interest to those buying those AD584LH voltage
>> reference modules containing a lithium battery from Ebay).
>>
>> And from
>>
>> http://www.flyingmag.com/news/ups-747-crash-highlights-lithium-battery-danger
>>
>> In a *recent report issued by the FAA in conjunction with Transport
>> Canada* <http://www.fire.tc.faa.gov/pdf/TC-13-2.pdf>, the agencies
>> predicted there will be an average of six cargo plane crashes between
>> now and 2021, with four of them likely to be caused by battery fires.
>> Read more at
>> http://www.flyingmag.com/news/ups-747-crash-highlights-lithium-battery-danger#1FZYPdiLXxLz0Fby.99
>> 'In a recent report issued by the FAA in conjunction with Transport
>> Canada, the agencies predicted there will be an average of six cargo
>> plane crashes between now and 2021, with four of them likely to be
>> caused by battery fires.'
>>
>> Tony H
>>
>> On 08/03/2014 22:32, Robert Atkinson wrote:
>> > Hi David,
>> > Our posts crossed. Note that the laptop battery has been independently
>> > safety tested. Or at least it should have been. Also you are no longer
>> > allowed to put batteries in you checked airline luggage, only carry-on
>> > and there are limits on the Lithium content (now expressed in WH to
>> > make it easier). This is pure safety addressing a very real hazard. The
>> > krytron restriction is ITAR (google it) as they are used to fire
>> > slapper detonators in nuclear weapons (that probably got a ping on a
>> > monitoring service;-).
>> >
>> > Robert G8RPI.
>> >
>> >
>> >
>> >
>> > ________________________________
>> >? From: David C. Partridge<david.partridge at perdrix.co.uk>
>> > To: 'Discussion of precise voltage measurement'<volt-nuts at febo.com>?
>> > Sent: Saturday, 8 March 2014, 22:04
>> > Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>> >?
>> >
>> > You can ship a Li-Ion or Li-Po battery inside a laptop no problem, but
>> > not
>> > on its own.
>> >
>> > No it doesn't make sense except to the postal/shipping/airline safety
>> > types.
>> > Probably the same logic that applies to exporting krytrons (even though
>> > Made
>> > in China applies to these too).anymore).
>> >
>> > Regards,
>> > David Partridge
>> > -----Original Message-----
>> > From:volt-nuts-bounces at febo.com? [mailto:volt-nuts-bounces at febo.com] On
>> > Behalf Of Chuck Harris
>> >
>> > Sent: 08 March 2014 21:36
>> > To: Discussion of precise voltage measurement
>> > Subject: Re: [volt-nuts] A Fluke 732A: Return it or keep it?
>> >
>> > Surely that isn't true... otherwise laptop computers and cell phones
>> > wouldn't be allowed on board passenger aircraft.? A laptop computer's
>> > battery would greatly exceed the power in the original 732A battery
>> > pack.
>> >
>> > -Chuck Harris
>> >
>> > _______________________________________________
>> > volt-nuts mailing list --volt-nuts at febo.com
>> > To unsubscribe, go
>> > tohttps://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> > and follow the instructions there.
>> > _______________________________________________
>> > volt-nuts mailing list --volt-nuts at febo.com
>> > To unsubscribe, go
>> > tohttps://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>> > and follow the instructions there.
>> >
>>
>> _______________________________________________
>> 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.
> ??? ??? ??? ? ??? ??? ?
>
> ------------------------------
>
> Message: 5
> Date: Sat, 8 Mar 2014 19:05:14 -0800 (PST)
> From: Bob Albert <bob91343 at yahoo.com>
> To: Discussion of precise voltage measurement <volt-nuts at febo.com>
> Subject: Re: [volt-nuts] Economical Standard Calibration
> Message-ID:
> ??? <1394334314.67677.YahooMailNeo at web122606.mail.ne1.yahoo.com>
> Content-Type: text/plain; charset=utf-8
>
> I have five AD587 switch selected, powered by a wall wart.? They seem to
> be very good, but of course not in the league of the units discussed here.
>
> In any case, they are 10V and all within about a millivolt.? If I average
> them I should get a statistically valid accuracy improvement, neglecting
> any systematic errors in their manufacture.
>
>
> While watching the display on my HP 3456A I begin to realize that my need
> for 'exact' voltage isn't really so great.? Certainly what I have is more
> accurate than anything I will ever really need.? But it's fun to see the
> variation and watch the drift and compare my other high class voltmeters.?
> The 3456A manual says to wait an hour for it to warm up and that seems
> reasonable; nearly all the drift is gone by about 45 minutes.
>
> Bob
>
>
>
>
> On Saturday, March 8, 2014 5:34 PM, Dallas Smith <dosmith at outlook.com>
> wrote:
>
> I'm in west Michigan, Holland. As far as accuracy the manual states?
> ?10ppm for 30 day or ?30ppm per year for the 10v output .
> I need it to calibrate my (modified with reference oven)? EDC (Electronic
> Development Corp.) model 520a. Which I calibrate my Fluke 510a with a
> Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my
> audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data
> Precision Model 2500.
>
> So if I can achieve ?50ppm per year this would be sufficient, but better
> would be nice since they may not be calibrated every year.
>
> I?m just a hobbies audio engineer that designs audiophile equipment and
> other interesting projects not related. So sending it to fluke is not
> economical for me.
>
> Since Joe suspended? operations for his SVR-T with low cost calibration. I
> purchased one and put it in a 35?C oven and it seems to outperform the
> Fluke 731b as compared to my 8505 for drift. I will have three 10 volt
> references in my lab to track uncertainty.
>
> So are there any calibration labs that will calibrate my 731a and my home
> brew reference?s?
>
>
>
>
>> Date: Sat, 8 Mar 2014 16:00:41 -0700
>> From: nova at npgcable.com
>> To: volt-nuts at febo.com
>> Subject: Re: [volt-nuts] Economical Standard Calibration
>>
>> Dallas,
>>
>> How accurately do you need the 731B set?
>>
>> Where are you located? I am in Flagstaff, Arizona
>>
>> I have four 731s, and I know how to calibrate them.
>>
>> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration
>> soon. I
>> do not know the turnaround time.
>>
>> Joe
>>
>>
>> On 3/8/2014 3:13 PM, Dallas Smith wrote:
>> > Good point, not a meter a Fluke 731b transfer standard. no access to
>> > local labs.
>> >
>> > On 3/8/2014 4:54 PM, Dr. David Kirkby wrote:
>> >> On 8 March 2014 21:44, Dallas Smith <dosmith at outlook.com> wrote:
>> >>> Hi nuts,
>> >>> This is my first post. The knowledge from contributors is amazing.
>> >>>
>> >>> Was wondering where one could economically get our_voltage standards
>> >>> calibrated_
>> >>> to some traceable standard since Joe Gellar suspended operations for
>> >>> his
>> >>> SVR-T?
>> >>>
>> >>> voltagestandard.com doesn't sell a 10v references and two of his 5v
>> >>> Vref5-002 are costly.
>> >>>
>> >>> Dallas
>> >> It would be worth stating what meter you have. Clearly what is going
>> >> to be useful for a 3.5 digit meter, will not be for an 8.5 digit 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
> 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
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>
> End of volt-nuts Digest, Vol 55, Issue 6
> ****************************************
>
> ------------------------------
>
> _______________________________________________
> volt-nuts mailing list
> volt-nuts at febo.com
> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
>
> End of volt-nuts Digest, Vol 55, Issue 7
> ****************************************
More information about the volt-nuts
mailing list