The new toy that I don't really need arrived :-) According to my uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages are very close to expected values and the increments via the switches are consistent. Not knowing the accuracy of either the DMM or the VS 330, I still thought it would be interesting to see what reading I got on the DMM with the VS 330 set to 5.00000 VDC. If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. I still need to get both the DMM and the VS 330 calibrated, but it is interesting that the only two voltage standards that I have seem to be in close agreement. Joe Gray W5JG

Accidents do happen. No, just kidding. Probably means all three are very close. Joe -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of Joseph Gray Sent: Friday, August 02, 2013 8:41 PM To: Discussion of precise voltage measurement Subject: [volt-nuts] VS 330 arrived The new toy that I don't really need arrived :-) According to my uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages are very close to expected values and the increments via the switches are consistent. Not knowing the accuracy of either the DMM or the VS 330, I still thought it would be interesting to see what reading I got on the DMM with the VS 330 set to 5.00000 VDC. If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. I still need to get both the DMM and the VS 330 calibrated, but it is interesting that the only two voltage standards that I have seem to be in close agreement. Joe Gray W5JG _______________________________________________ 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, To check the differences between the two references, connect the commons and put your 3478A meter beween the positive outputs. The meter will read the difference. As it should be less than 3V the 3478A will be in high impedance mode so loading will be minimised. Reverse the connectons and average the two readings to eliminate thermal EMFs. If the VS330 has fine enough adjustment you can zero the indicated difference. If the average meter reading and the adjustment of the reference for zero match, you have a good confidence for the difference between the two standards. Now you just need a third standard, maybe a Kelvin Varley divider, another meter............. Robert G8RPI, ________________________________ From: J. L. Trantham <jltran@att.net> To: 'Discussion of precise voltage measurement' <volt-nuts@febo.com> Sent: Saturday, 3 August 2013, 4:24 Subject: Re: [volt-nuts] VS 330 arrived Accidents do happen. No, just kidding.  Probably means all three are very close. Joe -----Original Message----- From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On Behalf Of Joseph Gray Sent: Friday, August 02, 2013 8:41 PM To: Discussion of precise voltage measurement Subject: [volt-nuts] VS 330 arrived The new toy that I don't really need arrived :-) According to my uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages are very close to expected values and the increments via the switches are consistent. Not knowing the accuracy of either the DMM or the VS 330, I still thought it would be interesting to see what reading I got on the DMM with the VS 330 set to 5.00000 VDC. If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. I still need to get both the DMM and the VS 330 calibrated, but it is interesting that the only two voltage standards that I have seem to be in close agreement. Joe Gray W5JG _______________________________________________ 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.

Some further data. Using three different (uncalibrated) DMMs, all three show exact x10 step increases in voltage for each rotary switch on the VS330. Although I'm not sure for the right-most switch. I'm in the noise of the LSD on my best DMM for that one. So, even though I don't know exactly how accurate this thing is, I feel pretty confident that it is working well. I've made a few inquiries about getting this calibrated. I'm still waiting on some answers. Joe Gray W5JG On Sat, Aug 3, 2013 at 4:28 AM, Robert Atkinson <robert8rpi@yahoo.co.uk>wrote: > Hi Joe, > To check the differences between the two references, connect the commons > and put your 3478A meter beween the positive outputs. The meter will read > the difference. As it should be less than 3V the 3478A will be in high > impedance mode so loading will be minimised. Reverse the connectons and > average the two readings to eliminate thermal EMFs. If the VS330 has fine > enough adjustment you can zero the indicated difference. If the average > meter reading and the adjustment of the reference for zero match, you have > a good confidence for the difference between the two standards. > Now you just need a third standard, maybe a Kelvin Varley divider, another > meter............. > > Robert G8RPI, > > > > > ________________________________ > From: J. L. Trantham <jltran@att.net> > To: 'Discussion of precise voltage measurement' <volt-nuts@febo.com> > Sent: Saturday, 3 August 2013, 4:24 > Subject: Re: [volt-nuts] VS 330 arrived > > > Accidents do happen. > > No, just kidding. Probably means all three are very close. > > Joe > > -----Original Message----- > From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On > Behalf Of Joseph Gray > Sent: Friday, August 02, 2013 8:41 PM > To: Discussion of precise voltage measurement > Subject: [volt-nuts] VS 330 arrived > > The new toy that I don't really need arrived :-) According to my > uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages > are very close to expected values and the increments via the switches are > consistent. > > Not knowing the accuracy of either the DMM or the VS 330, I still thought > it would be interesting to see what reading I got on the DMM with the VS > 330 set to 5.00000 VDC. > > If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. > Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. > > I still need to get both the DMM and the VS 330 calibrated, but it is > interesting that the only two voltage standards that I have seem to be in > close agreement. > > Joe Gray > W5JG > _______________________________________________ > 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. > _______________________________________________ > 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. > >

I borrowed the Fluke 189 from work. This is the newest and best DMM we have. It has one fewer digit than the HP 3478A. Hooked it up to the VS330. At 300 mV and below, the 189 showed one count less than the VS330 was set for, but occasionally showed the exact value. Above 300 mV, the 189 was dead on at all voltage settings. The more meters I compare, the more I'm seeing a trend that indicates the output of the VS330 is pretty darned accurate. I'd like to get my hands on a 7-8 digit DMM to check the very low end. I'm confident that the decade steps on the rotary switches are accurate. Every meter I try shows exactly x10 for each switch, on various ranges. I know that the VS330 is designed to be a "portable" standard, but I've left it powered on since I received it. I figure that this will give me the most stable output. Joe Gray W5JG On Tue, Aug 6, 2013 at 10:49 PM, Joseph Gray <jgray@zianet.com> wrote: > Some further data. Using three different (uncalibrated) DMMs, all three > show exact x10 step increases in voltage for each rotary switch on the > VS330. Although I'm not sure for the right-most switch. I'm in the noise of > the LSD on my best DMM for that one. So, even though I don't know exactly > how accurate this thing is, I feel pretty confident that it is working well. > > I've made a few inquiries about getting this calibrated. I'm still waiting > on some answers. > > Joe Gray > W5JG > > > > On Sat, Aug 3, 2013 at 4:28 AM, Robert Atkinson <robert8rpi@yahoo.co.uk>wrote: > >> Hi Joe, >> To check the differences between the two references, connect the commons >> and put your 3478A meter beween the positive outputs. The meter will read >> the difference. As it should be less than 3V the 3478A will be in high >> impedance mode so loading will be minimised. Reverse the connectons and >> average the two readings to eliminate thermal EMFs. If the VS330 has fine >> enough adjustment you can zero the indicated difference. If the average >> meter reading and the adjustment of the reference for zero match, you have >> a good confidence for the difference between the two standards. >> Now you just need a third standard, maybe a Kelvin Varley divider, >> another meter............. >> >> Robert G8RPI, >> >> >> >> >> ________________________________ >> From: J. L. Trantham <jltran@att.net> >> To: 'Discussion of precise voltage measurement' <volt-nuts@febo.com> >> Sent: Saturday, 3 August 2013, 4:24 >> Subject: Re: [volt-nuts] VS 330 arrived >> >> >> Accidents do happen. >> >> No, just kidding. Probably means all three are very close. >> >> Joe >> >> -----Original Message----- >> From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On >> Behalf Of Joseph Gray >> Sent: Friday, August 02, 2013 8:41 PM >> To: Discussion of precise voltage measurement >> Subject: [volt-nuts] VS 330 arrived >> >> The new toy that I don't really need arrived :-) According to my >> uncalibrated HP 3478A, the VS 330 seems to be working fine. The voltages >> are very close to expected values and the increments via the switches are >> consistent. >> >> Not knowing the accuracy of either the DMM or the VS 330, I still thought >> it would be interesting to see what reading I got on the DMM with the VS >> 330 set to 5.00000 VDC. >> >> If you remember, with the MAX6350CPA, the DMM measured 5.0026 VDC @ 26 C. >> Using the VS 330, the DMM reads 5.0020 VDC @ 26 C. >> >> I still need to get both the DMM and the VS 330 calibrated, but it is >> interesting that the only two voltage standards that I have seem to be in >> close agreement. >> >> Joe Gray >> W5JG >> _______________________________________________ >> 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. >> _______________________________________________ >> 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. >> >> >