Re: [volt-nuts] Prema 6048 Cal switch confusion
How about copying the contents of the old nvram to the new one? - Original Message - From: "David C. Partridge" To: "'Discussion of precise voltage measurement'" Sent: Thursday, November 02, 2017 2:58 PM Subject: Re: [volt-nuts] Prema 6048 Cal switch confusion Update - when I tried this I was using a brand new DS1220AD-100IND (blank) to replace the DS1220Y. Reinstalling the DS1220Y and it worked as expected! Processor must detect cal mode by writing to NVRAM - if succeeds, then in Cal mode??? Maybe Is there some obscure incompatability between the DS1220AD and the DS1220Y??? Dave -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: 02 November 2017 18:23 To: 'Discussion of precise voltage measurement' Subject: [volt-nuts] Prema 6048 Cal switch confusion I've got a Perma 6048 that I've trying to put into Cal mode. It just won't! The switch on the rear panel works OK, AFAICT when in the Cal position it connects ~WE on the DS1220 (pin 21) and ~W on the $864 SRAM (pin 27) to a 4K7 pullup to +5V and to the output of an LS00 which should be strobing the Write lines low as needed. I can't see any way in which the processor can be informed of the switch setting! In measure mode it just connects ~WE on the DS1220 to a 10k pullup to +5V. The schematic is on page 120 (Figure 11.4) of the user manual and also page 9-7 of the service manual. Clearly I'm missing something - as a friend reports that his does go into cal mode. Confused ... Thanks 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. ___ 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] Prema 6048 Cal switch confusion
Update - when I tried this I was using a brand new DS1220AD-100IND (blank) to replace the DS1220Y. Reinstalling the DS1220Y and it worked as expected! Processor must detect cal mode by writing to NVRAM - if succeeds, then in Cal mode??? Maybe Is there some obscure incompatability between the DS1220AD and the DS1220Y??? Dave -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of David C. Partridge Sent: 02 November 2017 18:23 To: 'Discussion of precise voltage measurement' Subject: [volt-nuts] Prema 6048 Cal switch confusion I've got a Perma 6048 that I've trying to put into Cal mode. It just won't! The switch on the rear panel works OK, AFAICT when in the Cal position it connects ~WE on the DS1220 (pin 21) and ~W on the $864 SRAM (pin 27) to a 4K7 pullup to +5V and to the output of an LS00 which should be strobing the Write lines low as needed. I can't see any way in which the processor can be informed of the switch setting! In measure mode it just connects ~WE on the DS1220 to a 10k pullup to +5V. The schematic is on page 120 (Figure 11.4) of the user manual and also page 9-7 of the service manual. Clearly I'm missing something - as a friend reports that his does go into cal mode. Confused ... Thanks 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. ___ 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] Prema 6048 Cal switch confusion
I've got a Perma 6048 that I've trying to put into Cal mode. It just won't! The switch on the rear panel works OK, AFAICT when in the Cal position it connects ~WE on the DS1220 (pin 21) and ~W on the $864 SRAM (pin 27) to a 4K7 pullup to +5V and to the output of an LS00 which should be strobing the Write lines low as needed. I can't see any way in which the processor can be informed of the switch setting! In measure mode it just connects ~WE on the DS1220 to a 10k pullup to +5V. The schematic is on page 120 (Figure 11.4) of the user manual and also page 9-7 of the service manual. Clearly I'm missing something - as a friend reports that his does go into cal mode. Confused ... Thanks 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.
[volt-nuts] HP 5335A Question
>The gate time on a 5335 can be set via GPIB. It can be set to some *very* long >gates (well past 100 seconds). >When you do this, the data reported on GPIB does “stretch” to cover the added >digits. The problem is that there >are internal register overflows. The designers did not anticipate needing >quite so many bits. You loose the MSB’s >when you go to long gates. Compensating for this on a reasonable source is not >a big deal. > Bob Hi Bob, You need to use timed GO and GC commands (Gate Open and Gate Close), for > 1sec Gate Time. The GA command (Gate Adjust) is restricted from 1ms to 1 sec Gate time, so will not do the job. See manual page 3-29. One error correction: I replaced this 10µF Gate Time capacitor with a Tantalum type, 33µF, obviously, as these original 10µF already give about 4sec, so the 33µF are good for 12.5 sec, 10 digits. The designers very well designed two near inifinite counter chains inside the 5335A.. I got my wisdom from the hp journal 9-1980. They used a digital ASIC, called the MRC, multi-register counter, and it allows counting of the input signal and the time base, each 20 decades long. (see page 26). Therefore, the Gate Time could be 300 000 years long, before an overflow from the 10MHz time base would occur, and the result would theoretically be precise to 20 digits resolution plus 2 digits for the time interpolator. So you will NEVER loose any MSB information. The GPIB output also does not stretch its resolution , because in the manual, they have a fixed digits output format. On second read (pages 3-32 .. 3-34), it's not limited to 9 digits - sorry for the confusion - they reserve 14 digits for the mantissa, including sign and comma, so up to 12 digits can be transferred also, like on the display.. that means, also 11 significant digits over GPIB. I assume, they internally use about 13 digits for the arithmetic routines, maybe taken over from the HP pocket calculators. Frank Mit TravelXtra profitieren Sie von 5% Rückvergütung auf den Reisepreis – bekannte dt. Reiseanbieter und ein umfangreiches Reiseangebot wie im Reisebüro! https://email.freenet.de/reisen/index.html ___ 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.
