Hi Bill -- The HP3458A has an AC measurement mode that for frequencies of 50kHz or less does an A-D conversion of sample points then calculates the RMS value, instead of the usual mode of rectifying the signal and the calulating the RMS. The outstanding linearity of the A-D in the 3458 means that it is very accurate, with much lower uncertainty than the 510s, and the cal data for the 3458, which is fairly recent tends to support this. So, I'm using it to look at the 510s outputs. I'm also a bit mystified why setting the 510s internal reference to the recommended 14.142136 VDC doesn't actually result in a 10VAC output; The peak detector-comparator circuit seems to have pretty good performance. I've tried varying the internal adjustments of the 510 one at a time to gauge effects on output level, and the only one that really seems to matter is the reference level setting. Any light youc an shed would be welcome. Ulrich, thanks for the kind offer. I hope to get into GPIB in the late spring or early summer. Best, Dick Moore > > Message: 4 > Date: Wed, 20 Jan 2010 13:50:55 -0800 > From: WB6BNQ <wb6bnq@cox.net> > Subject: Re: [volt-nuts] First post > To: Discussion of precise voltage measurement <volt-nuts@febo.com> > Message-ID: <4B577ABF.992F8E02@cox.net> > Content-Type: text/plain; charset=us-ascii > > Hi Dick, > > Out of curiousity how are you determining that the 510's are drifty ? > > Bill....WB6BNQ > > > Dick Moore wrote: > >> Hi all. This is my first post to volt-nuts. Glad to find this list; got here from time-nuts. My little lab (on the western shore of Puget Sound) has a couple of Fluke 732A DC Refs, an HP 3458A (no options), a Datron 1082 DMM, a Fluke 5440B Direct Volts Calibrator, a couple of Fluke 510A AC Standards (400Hz and 40kHz), and a variety of resistance standards, other bridges, meters, etc. >> >> I hope to make time to dig around in the archives. For now, I'm interested in any experience you all have with the long-term drift of the Fluke/Motorola reference modules used in the 732s, the 5440 and the 510s (as well as the 850x series of meters). I'm also wondering about the stability of the 510s in particular, which seem very drift prone and highly temperature sensitive -- comments and any practical mods welcome. Has anyone subbed in an LTZ1000A in any of these units? >> >> I hope to begin using a Prologix USB>GPIB converter, yet to be purchased, for data gathering and control, via Ulrich's EasyGPIB >> >> Best, >> Dick Moore >> _______________________________________________ >> 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. > > > > > ------------------------------ > > Message: 5 > Date: Thu, 21 Jan 2010 09:36:37 +0100 > From: "Ulrich Bangert" <df6jb@ulrich-bangert.de> > Subject: Re: [volt-nuts] First post > To: "'Discussion of precise voltage measurement'" <volt-nuts@febo.com> > Message-ID: <4EE06AF31FB7453686157B8EAB043E73@athlon> > Content-Type: text/plain; charset="us-ascii" > > Dick, > >> I hope to begin using a Prologix USB>GPIB converter, yet to >> be purchased, for data gathering and control, via Ulrich's EasyGPIB > > Should you need any assistance, don't hesitate to contact me directly! > > Best regards > Ulrich > >> -----Ursprungliche Nachricht----- >> Von: volt-nuts-bounces@febo.com >> [mailto:volt-nuts-bounces@febo.com] Im Auftrag von Dick Moore >> Gesendet: Mittwoch, 20. Januar 2010 22:19 >> An: volt-nuts@febo.com >> Betreff: [volt-nuts] First post >> >> >> Hi all. This is my first post to volt-nuts. Glad to find this >> list; got here from time-nuts. My little lab (on the western >> shore of Puget Sound) has a couple of Fluke 732A DC Refs, an >> HP 3458A (no options), a Datron 1082 DMM, a Fluke 5440B >> Direct Volts Calibrator, a couple of Fluke 510A AC Standards >> (400Hz and 40kHz), and a variety of resistance standards, >> other bridges, meters, etc. >> >> I hope to make time to dig around in the archives. For now, >> I'm interested in any experience you all have with the >> long-term drift of the Fluke/Motorola reference modules used >> in the 732s, the 5440 and the 510s (as well as the 850x >> series of meters). I'm also wondering about the stability of >> the 510s in particular, which seem very drift prone and >> highly temperature sensitive -- comments and any practical >> mods welcome. Has anyone subbed in an LTZ1000A in any of these units? >> >> I hope to begin using a Prologix USB>GPIB converter, yet to >> be purchased, for data gathering and control, via Ulrich's EasyGPIB >> >> Best, >> Dick Moore

Hi Dick, Well, first the obvious question. Have you gone through the complete calibration procedure ? When you say ". . . doesn't actually result in a 10VAC output," just how far off do you think it is ? Have you looked at the output waveform on the scope ? Actually you should measure it with a distortion analyzer, if you have one. If it isn't clean that would through off the RMS value. It could also, possibly, fool the peak detector. If you think about it, the 14.142136 is 10 times the square root of 2 (close enough anyway) and would be the precise peak value of the 10 volt RMS level (RMS being 1/2 SQRT of 2 times the peak value). If the waveform is "clean," perhaps there may be an issue with the integrator that follows the peak detector. Also, your statement about the 510 ". . . which seem very drift prone and highly temperature sensitive," how much variation are you are seeing ? Again, I am wondering if there may be an issue with the integrator. Perhaps the integrating capacitor has a problem or maybe there is some additional leakage around the integrating capacitor and the input of the integrator circuit that should not be there. It could have been sprayed with something that has left a film that reacts to moisture. If that is the case, then spraying it with a good soap like 409, a little brushing and rinsing with distilled water should take care of that. Just make sure not to get the transformers wet. If they do get a little wet, then baking it out in a cardboard box with a 100 watt incandescent light as a heat source for 2 to 3 days. Obviously you may want to have some venting of the box to control the temp so the plastic parts do not melt. But you should be able to have around 150 degree F without a problem. Bill....WB6BNQ Dick Moore wrote: > Hi Bill -- The HP3458A has an AC measurement mode that for frequencies of 50kHz or less does an A-D conversion of sample points then calculates the RMS value, instead of the usual mode of rectifying the signal and the calulating the RMS. The outstanding linearity of the A-D in the 3458 means that it is very accurate, with much lower uncertainty than the 510s, and the cal data for the 3458, which is fairly recent tends to support this. So, I'm using it to look at the 510s outputs. I'm also a bit mystified why setting the 510s internal reference to the recommended 14.142136 VDC doesn't actually result in a 10VAC output; The peak detector-comparator circuit seems to have pretty good performance. I've tried varying the internal adjustments of the 510 one at a time to gauge effects on output level, and the only one that really seems to matter is the reference level setting. Any light youc an shed would be welcome. > > Ulrich, thanks for the kind offer. I hope to get into GPIB in the late spring or early summer. > > Best, > Dick Moore > > > > > Message: 4 > > Date: Wed, 20 Jan 2010 13:50:55 -0800 > > From: WB6BNQ <wb6bnq@cox.net> > > Subject: Re: [volt-nuts] First post > > To: Discussion of precise voltage measurement <volt-nuts@febo.com> > > Message-ID: <4B577ABF.992F8E02@cox.net> > > Content-Type: text/plain; charset=us-ascii > > > > Hi Dick, > > > > Out of curiousity how are you determining that the 510's are drifty ? > > > > Bill....WB6BNQ > > > > > > Dick Moore wrote: > > > >> Hi all. This is my first post to volt-nuts. Glad to find this list; got here from time-nuts. My little lab (on the western shore of Puget Sound) has a couple of Fluke 732A DC Refs, an HP 3458A (no options), a Datron 1082 DMM, a Fluke 5440B Direct Volts Calibrator, a couple of Fluke 510A AC Standards (400Hz and 40kHz), and a variety of resistance standards, other bridges, meters, etc. > >> > >> I hope to make time to dig around in the archives. For now, I'm interested in any experience you all have with the long-term drift of the Fluke/Motorola reference modules used in the 732s, the 5440 and the 510s (as well as the 850x series of meters). I'm also wondering about the stability of the 510s in particular, which seem very drift prone and highly temperature sensitive -- comments and any practical mods welcome. Has anyone subbed in an LTZ1000A in any of these units? > >> > >> I hope to begin using a Prologix USB>GPIB converter, yet to be purchased, for data gathering and control, via Ulrich's EasyGPIB > >> > >> Best, > >> Dick Moore > >> _______________________________________________ > >> 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. > > > > > > > > > > ------------------------------ > > > > Message: 5 > > Date: Thu, 21 Jan 2010 09:36:37 +0100 > > From: "Ulrich Bangert" <df6jb@ulrich-bangert.de> > > Subject: Re: [volt-nuts] First post > > To: "'Discussion of precise voltage measurement'" <volt-nuts@febo.com> > > Message-ID: <4EE06AF31FB7453686157B8EAB043E73@athlon> > > Content-Type: text/plain; charset="us-ascii" > > > > Dick, > > > >> I hope to begin using a Prologix USB>GPIB converter, yet to > >> be purchased, for data gathering and control, via Ulrich's EasyGPIB > > > > Should you need any assistance, don't hesitate to contact me directly! > > > > Best regards > > Ulrich > > > >> -----Ursprungliche Nachricht----- > >> Von: volt-nuts-bounces@febo.com > >> [mailto:volt-nuts-bounces@febo.com] Im Auftrag von Dick Moore > >> Gesendet: Mittwoch, 20. Januar 2010 22:19 > >> An: volt-nuts@febo.com > >> Betreff: [volt-nuts] First post > >> > >> > >> Hi all. This is my first post to volt-nuts. Glad to find this > >> list; got here from time-nuts. My little lab (on the western > >> shore of Puget Sound) has a couple of Fluke 732A DC Refs, an > >> HP 3458A (no options), a Datron 1082 DMM, a Fluke 5440B > >> Direct Volts Calibrator, a couple of Fluke 510A AC Standards > >> (400Hz and 40kHz), and a variety of resistance standards, > >> other bridges, meters, etc. > >> > >> I hope to make time to dig around in the archives. For now, > >> I'm interested in any experience you all have with the > >> long-term drift of the Fluke/Motorola reference modules used > >> in the 732s, the 5440 and the 510s (as well as the 850x > >> series of meters). I'm also wondering about the stability of > >> the 510s in particular, which seem very drift prone and > >> highly temperature sensitive -- comments and any practical > >> mods welcome. Has anyone subbed in an LTZ1000A in any of these units? > >> > >> I hope to begin using a Prologix USB>GPIB converter, yet to > >> be purchased, for data gathering and control, via Ulrich's EasyGPIB > >> > >> Best, > >> Dick Moore > > _______________________________________________ > 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.