Re: [volt-nuts] Calibration and Certification - Trust and detail
Hi , Newer does not mean better. It's not nuts level, but my Fluke 8060A 4.5 digit handhelds are more accurate and stable than my newer 89 IV. However most engineers would pick up the 89. I agree with Dave on UK engineers For many years I've been a member of the very few groups of engineer in the UK who need a licence to do their job - aircraft, but even that has been diluted since EU regulations came into force. I'm also a Chartered Engineer similar to PE in the USA. As I understand it most US States require you to be a PE before you can do business as an Engineer. In the UK it's a bloke with an oily rag and big hammer :-( Robert CEng MRAeS G8RPI From: Orin Eman orin.e...@gmail.com To: Discussion of precise voltage measurement volt-nuts@febo.com Sent: Tuesday, 13 August 2013, 5:56 Subject: Re: [volt-nuts] Calibration and Certification - Trust and detail On Sun, Aug 11, 2013 at 3:36 PM, Orin Eman orin.e...@gmail.com wrote: I should go get the kelvin clips out and compare the 3456A against the '61A on some 10k precision wirewound resistors I have. I did. The resistors are MR102 series 0.01% 1/8W wirewound: 34461A: 10.000 82 +/- 0.000 90 3456A: 10.000 98 +/- 0.000 58 Using 90 day specs for the 61A and 90 day plus 0.0004% per month for the 56A. Yes, the 3456A resistance specs are better than the shiny new 34461A. I also compared the DC voltage ranges from 0.1 to 1000V and other than on the 1KV range, results were within 10ppm. Still, given the 3456A spec sheet says add .12(input voltage/1000)^2 % on the 1KV range, I can't complain; I got 999.984 on the 61A and 1000.062 on the 56A. I'm pretty sure that the superscript 2 in the spec meant squared, not that it matters for 1000/1000. Now has anyone calibrated a Fluke 343A? The instructions in the manual are entertaining. They tell you to adjust the 1000V range to +/- 1mV, but the post calibration check says that a freshly calibrated unit should be +/- 100uV at the 1000V setting. Orin. ___ 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
On Mon, Aug 12, 2013 at 9:56 PM, Orin Eman orin.e...@gmail.com wrote: Still, given the 3456A spec sheet says add .12(input voltage/1000)^2 % on the 1KV range... Make that .012*(input voltage/1000)^2 %... Oops. Orin. ___ 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
Its one reason to obtain a 3456a and keep as a reference DMM, you can take the modern meter as a workhorse and give it wear and tear. Now a choice between the 3456a and 3457a I leave to the owner's need for the trade offs between them. At 02:17 AM 8/13/2013, Robert Atkinson wrote: Hi , Newer does not mean better. It's not nuts level, but my Fluke 8060A 4.5 digit handhelds are more accurate and stable than my newer 89 IV. However most engineers would pick up the 89. I agree with Dave on UK engineers For many years I've been a member of the very few groups of engineer in the UK who need a licence to do their job - aircraft, but even that has been diluted since EU regulations came into force. I'm also a Chartered Engineer similar to PE in the USA. As I understand it most US States require you to be a PE before you can do business as an Engineer. In the UK it's a bloke with an oily rag and big hammer :-( Robert CEng MRAeS G8RPI ___ 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
On 12 August 2013 01:58, Charles Steinmetz csteinm...@yandex.com wrote: David wrote: How useful is this http://www.ebay.com/itm/281149723636 ? On the fact of it, the device would give one a reasonly high confidence something is working readlably well. I wonder if that is good enough for a 3457A. Let's assume that it is still working exactly the same as it was when it was calibrated. The calibration values are recorded to 4-1/2 digits. So the uncertainty is greater than the two LSDs of a 3457A. Of course, it is almost certainly not working exactly the same as it was when it was calibrated, which is going to put at least the third LSD of a 3457A in question. So it is good enough for a 3457A only if one is content with a 3-1/2 digit verification on a 6-1/2 digit instrument. Best regards, Charles Thank you Charles. Yes, on checking the spec I can see it wont be any use. 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
On Sun, Aug 11, 2013 at 3:36 PM, Orin Eman orin.e...@gmail.com wrote: I should go get the kelvin clips out and compare the 3456A against the '61A on some 10k precision wirewound resistors I have. I did. The resistors are MR102 series 0.01% 1/8W wirewound: 34461A: 10.000 82 +/- 0.000 90 3456A: 10.000 98 +/- 0.000 58 Using 90 day specs for the 61A and 90 day plus 0.0004% per month for the 56A. Yes, the 3456A resistance specs are better than the shiny new 34461A. I also compared the DC voltage ranges from 0.1 to 1000V and other than on the 1KV range, results were within 10ppm. Still, given the 3456A spec sheet says add .12(input voltage/1000)^2 % on the 1KV range, I can't complain; I got 999.984 on the 61A and 1000.062 on the 56A. I'm pretty sure that the superscript 2 in the spec meant squared, not that it matters for 1000/1000. Now has anyone calibrated a Fluke 343A? The instructions in the manual are entertaining. They tell you to adjust the 1000V range to +/- 1mV, but the post calibration check says that a freshly calibrated unit should be +/- 100uV at the 1000V setting. Orin. ___ 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
On 11 August 2013 15:39, Robert Atkinson robert8...@yahoo.co.uk wrote: On a related issue to the 3457A calibration, I was asked to review an item at work last week (sorry can't say what or why). Looking at compliance certification by two fully qualified, internationally recognised labs, all looked well until I looked at the detail. Things like ..all RELEVANT requirements of.. (my capitals) with no list of what was relevant or any test report., details of only one test when the standard needed a number under different conditions, no record of the part or serial numbers of the unit tested. Others had accepted the certification at face value. I think it depens why you want the cal certificate. 1) If it to keep the BSI person happy to keep your ISO 9001 acreditation, then I guess as long as it has a cal certificate that is ok, so use the cheapest dodgy cal lab. 2) If the purpose of the cal certificate is to get the highest price when selling something, then a cal certificate by some dodgy cal lab is probably all you need. 99% of buyers are not going to question who did the cal, and their ability to do it. 3) If you want to know the instrument works correctly, and have it adjusted for best performance, then it is a very different matter. One is probably better sending it to the manufacturer in many cases. I want to know my VNA works properly, so that is going to Agilent this week. The cal cost on my VNA is about 5% of what I paid for the VNA. It would be much more difficult to justify sending my 3457A to Agilent, when the cal cost will probably be more than what I paid for the instrument. How useful is this http://www.ebay.com/itm/281149723636 ? On the fact of it, the device would give one a reasonly high confidence something is working readlably well. I wonder if that is good enough for a 3457A. Unfortunatly if the test house customer says just do this bit and the test house is happy to put weasely words on the certifcate, then user beware. As I wrote earlier, I think there is a very cosy relationship between cal labs and test equipment dealers. It is in both their interests to get cal certificates on items even if they are not 100%. A T+M dealer is not likely to use a cal lab that keeps sending items back marked Out of specification or similar. A cal lab does not want to lose a customer. Robert G8RPI. Dave, G8WRB. ___ 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.
Re: [volt-nuts] Calibration and Certification - Trust and detail
David wrote: How useful is this http://www.ebay.com/itm/281149723636 ? On the fact of it, the device would give one a reasonly high confidence something is working readlably well. I wonder if that is good enough for a 3457A. Let's assume that it is still working exactly the same as it was when it was calibrated. The calibration values are recorded to 4-1/2 digits. So the uncertainty is greater than the two LSDs of a 3457A. Of course, it is almost certainly not working exactly the same as it was when it was calibrated, which is going to put at least the third LSD of a 3457A in question. So it is good enough for a 3457A only if one is content with a 3-1/2 digit verification on a 6-1/2 digit instrument. Best regards, Charles ___ 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.
