Re: [volt-nuts] HP 3457A calibration?
I've tried this on a 3458A and lost the data in the CALRAM due (I think) to trying to read the data while the chip was still 'hot' from the removal process. Two other 3458A's were successful. I've tried this on a 3478A (much more like the 3457A) and lost the data and had to recalibrate the unit. I have not sent it to Agilent for calibration to see how 'successful' my 'home cal' was. I know safe removal and replacement of the battery can be done and has been done. However, I really missed knowing the 'in tolerance' status of the 3458A. I returned it to Agilent earlier this year and it was 'in tolerance' from the calibration the previous year, so that is some consolation. The other two 3458A's, that underwent the 'successful' CALRAM replacement, were both 'in tolerance' when returned to Agilent and again were earlier this year, thus giving confidence that they are stable for a long term and likely not needing 'calibration' on a yearly basis. I recently sent two Fluke 289, 4 1/2 digit handheld, DMM's to Fluke for calibration, one with a Calibration Date of 08/07/09 and Calibration Counter of 1 and the other with a Calibration Date of 02/10/11 and Calibration Counter of 1, and both returned with 'As Found - As Left' data and no adjustments made (Fluke Z540 Cal). This gives me great confidence in the DMM's and their ability to be accurate for many years to come with little need to return them to Fluke for 'cal'. It would appear that they have been 'in tolerance' since their original calibrations some 2 to 4 years ago. >From my perspective, as a 'neophyte volt-nut', knowing the 'in tolerance' status of the DMM is very 'confidence building'. That's all I'm trying to say. Again, good luck. Joe -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Joseph Gray Sent: Tuesday, August 20, 2013 11:15 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP 3457A calibration? I have replaced this type of battery in other equipment, so it isn't a big deal for me. I'm sure I can do it without losing the cal data. Joe Gray W5JG On Aug 20, 2013 9:43 AM, "Dr. David Kirkby" wrote: > On 20 August 2013 14:51, J. L. Trantham wrote: > > If the battery is 'OK', I would favor just sending it to Agilent for > > calibration, unless you can 'SAFELY' change the battery while > > preserving > the > > cal data. > > > > Good luck. > > > > Joe > > If one accepts there is some risk changing the battery while > preserving the data, one has two choices. > > 1) Do as you say and leave the battery, preserving the cal data. This > however risk the battery leaking at some time. > 2) Change the battery, losing the cal data, but virtually eliminating > the risk of leakage. > > To me at least, the path of least risk is the one to take. > > I suspect if one put a power supply in parallel with the battery with > a 10 k resistor in series, then the 10 k resistor would not drop > enough voltage to lose the ram data, but if it was accidently shorted > the current would be limited to a few hundred microamps. That's > unlikely to do any damage > > I guess for a volt nut, preserving the cal data is more important than > it is to me. Not damaging the meter is higher on my priority list. > > 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] Datron 4910 components
Thanks Frank, much appreciated! Steve WB0DBS On Aug 20, 2013, at 4:27 PM, Frank Stellmach wrote: > Steve, > > yep, it's in the LTZ100 thread. > We discussed intensively the sense or nonsense of those slots in the Datron > PCB design, which is very often (blindly) copied by others... > > Mickle T. contributed the already known schematics and he measured all > resistor values of the Vishay array. > > Then, quarks simply added a schematic of this array, which he received > directly from Vishay, obviously. > > So, Datron used 21 Ohm in series with the Zener for better T.C. (originally > 50ppm/K), 9k/659 as initial divider for temperature regulation (altered by > the external temp. PWM), 128 Ohm for the Zener current, 39k as collector > resistor for the reference transistor. > > There's no complete schematic yet, but now it's possible to finalize that. > > Here's the link: > > http://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/300/ > > Frank > ___ > 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] Datron 4910 components
Steve, yep, it's in the LTZ100 thread. We discussed intensively the sense or nonsense of those slots in the Datron PCB design, which is very often (blindly) copied by others... Mickle T. contributed the already known schematics and he measured all resistor values of the Vishay array. Then, quarks simply added a schematic of this array, which he received directly from Vishay, obviously. So, Datron used 21 Ohm in series with the Zener for better T.C. (originally 50ppm/K), 9k/659 as initial divider for temperature regulation (altered by the external temp. PWM), 128 Ohm for the Zener current, 39k as collector resistor for the reference transistor. There's no complete schematic yet, but now it's possible to finalize that. Here's the link: http://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/300/ Frank ___ 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] Fluke 732B
Frank, Have you got a link to the eevblog Datron 4910 reference element decryption? I have a 4910 and am curious to see what they found, but am not finding any reference to it in their "Episode" list. Thanks Steve On Aug 20, 2013, at 12:01 PM, Frank Stellmach wrote: > Hello, > > until now, nobody has ever reenginered the 732B schematics. Perhaps the > bbs.38hot colleagues (lymex et. al.) have done that, but I do not get access > to the forum for downloading anything, either. > > But on eevblog, the Datron 4910 reference element has been decrypted > completely, as now the content of the Vishay resistor array is known. > Yep, I have to admit, that I also have made much more effort there than here > lately. See 'Ultra precision reference LTZ1000'. > > Anyhow, in the 732B manual, there is that circuit block diagram, showing the > usual reference amplifier circuitry. > Fluke added some current cancellation circuitry compared to the 732A, and has > put all temperature sensitive components inside the oven. > That includes especially the 4-5 precision wirewound resistors around the > ref. amp., which cause the most drift over temperature and time. > > I think that's all with 732Bs magic. > > The 732B had two series, one earlier with the SZA263 (Motorola) and after > termination of that part, a compatible 2nd source from LT, the LTFLU refence > amplifier. > > The mentioned Fluke / Deaver document analyses the different drift behaviour > of those two components, but in general, the 732A (based on the SZA263) was > less stable, afaik. > > Frank > ___ > 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] HP 3457A calibration?
On 20 August 2013 17:14, Joseph Gray wrote: > I have replaced this type of battery in other equipment, so it isn't a big > deal for me. I'm sure I can do it without losing the cal data. > > Joe Gray > W5JG Given the discussion on here a week or two ago about Agilent not adjusting something if it is spec, there may be some advantage in not having the ram contents kept. That way the meter is sure to require adjustment and do wll be adjusted as close as possible. Whilst that may not suite a metrologist who wants to track drift over time, it suits me better to have it made as close as possible, ratther than just left if within spec. 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] HP 3457A calibration?
If you count each calibration procedure in the manual, you get 16. If you count each scale in each procedure, it is several times that. I suspect that the calnum is only incremented for each procedure. Joe Gray W5JG On Aug 20, 2013 1:10 PM, "Joseph Gray" wrote: > I've watched a few of his videos and they are all like that. Considering > his apparent knowledge level and how boring he is, I probably won't bother > with his other videos. > > Joe Gray > W5JG > On Aug 20, 2013 11:48 AM, "Dr. David Kirkby" wrote: > >> On 20 August 2013 15:27, Rob Klein wrote: >> > Good video for when I can't get to sleep, though >> >> Yes, it does really drag on. He could say what he has to say in 25% of >> the time, by cutting out all the irrelevant rubbish. >> >> 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.
Re: [volt-nuts] Fluke 732B
That's what happens when I type emails on my phone :-) I'm still envious of your voltage standards. Joe Gray W5JG On Aug 20, 2013 11:13 AM, "Bill Gold" wrote: > Joe: > > Thanks for the upgrade, but they are only 732As not Bs. I got all of > these at less than the going price of one 732B that recently sold on the > infamous action site. > > Bill > ___ > 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] HP 3457A calibration?
I've watched a few of his videos and they are all like that. Considering his apparent knowledge level and how boring he is, I probably won't bother with his other videos. Joe Gray W5JG On Aug 20, 2013 11:48 AM, "Dr. David Kirkby" wrote: > On 20 August 2013 15:27, Rob Klein wrote: > > Good video for when I can't get to sleep, though > > Yes, it does really drag on. He could say what he has to say in 25% of > the time, by cutting out all the irrelevant rubbish. > > 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.
Re: [volt-nuts] HP 3457A calibration?
On 20 August 2013 15:27, Rob Klein wrote: > Good video for when I can't get to sleep, though Yes, it does really drag on. He could say what he has to say in 25% of the time, by cutting out all the irrelevant rubbish. 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] Fluke 732B
Hello, until now, nobody has ever reenginered the 732B schematics. Perhaps the bbs.38hot colleagues (lymex et. al.) have done that, but I do not get access to the forum for downloading anything, either. But on eevblog, the Datron 4910 reference element has been decrypted completely, as now the content of the Vishay resistor array is known. Yep, I have to admit, that I also have made much more effort there than here lately. See 'Ultra precision reference LTZ1000'. Anyhow, in the 732B manual, there is that circuit block diagram, showing the usual reference amplifier circuitry. Fluke added some current cancellation circuitry compared to the 732A, and has put all temperature sensitive components inside the oven. That includes especially the 4-5 precision wirewound resistors around the ref. amp., which cause the most drift over temperature and time. I think that's all with 732Bs magic. The 732B had two series, one earlier with the SZA263 (Motorola) and after termination of that part, a compatible 2nd source from LT, the LTFLU refence amplifier. The mentioned Fluke / Deaver document analyses the different drift behaviour of those two components, but in general, the 732A (based on the SZA263) was less stable, afaik. Frank ___ 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] Fluke 732B
Joe: Thanks for the upgrade, but they are only 732As not Bs. I got all of these at less than the going price of one 732B that recently sold on the infamous action site. Bill ___ 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] Fluke 732B
Bill, With six 732B's, you certainly qualify as a volt nut. Joe Gray W5JG On Aug 20, 2013 10:37 AM, "Bill Gold" wrote: > Joe: > > The 731A and 731B were run at room temp and therefore were subject to > room variations. They both use the same "Reference Amplifier" as the 732A > & B use. I have one 731B and it is amazingly stable for the room temp > variations I experience at home. When I was working we had a 731B that was > also very good. I had sent it for calibration over a 10 year period and > the drift was equal to, or better than the 732 series. At the end of the > 10 years it was absolutely stable at less than 1 ppm. This was all being > done at a Fluke Service Center that was located in Milpitas California, and > their 732As were being routinely sent to Fluke in Everett WA. > > The difference between the 731 & 732 is that starting with the 732A > all of the temperature sensitive components were enclosed in a oven > assembly that had heaters surrounding the oven enclosure which is running > at 45 degrees C. This includes all of the resistors and adjustment pots. > I have torn down a 732A to the oven assembly and gone inside the assembly > to replace a component. It is a real trick to do this, but by being > careful it can be done. > > The fact that the 732As have been in operation for a much longer > period of time probably explains the lower drift rates than the 732Bs. The > 732As have been "aged" much longer. I know people who prefer the 732A over > the 732B because of this. The only problem with the 732A is that the > heaters use more power than the 732Bs. Early manuals spec 24 hour battery > operation, but later manuals have changed that to 12 hours. All of the > 732As I have observed will only run for about 12 to 15 hours before the "in > cal" light goes out meaning that the batteries have dropped below about 22 > volts. The 732B is speced at 72 hours battery operation but I have no > experience if this is true. > > I guess I am a real "Volt-Nut" in that I have 6 732As at home right > now. I inter-compare them once a week. The last time I was able to verify > what the official "volt" is was in 2005. Right now I need to find a good > Cal Lab in the South SF Bay Area where I can have one of them "certified" > against their traceable standards. The Fluke service center was closed > years ago. > > Bill > ___ > 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] Fluke 732B
Joe: The 731A and 731B were run at room temp and therefore were subject to room variations. They both use the same "Reference Amplifier" as the 732A & B use. I have one 731B and it is amazingly stable for the room temp variations I experience at home. When I was working we had a 731B that was also very good. I had sent it for calibration over a 10 year period and the drift was equal to, or better than the 732 series. At the end of the 10 years it was absolutely stable at less than 1 ppm. This was all being done at a Fluke Service Center that was located in Milpitas California, and their 732As were being routinely sent to Fluke in Everett WA. The difference between the 731 & 732 is that starting with the 732A all of the temperature sensitive components were enclosed in a oven assembly that had heaters surrounding the oven enclosure which is running at 45 degrees C. This includes all of the resistors and adjustment pots. I have torn down a 732A to the oven assembly and gone inside the assembly to replace a component. It is a real trick to do this, but by being careful it can be done. The fact that the 732As have been in operation for a much longer period of time probably explains the lower drift rates than the 732Bs. The 732As have been "aged" much longer. I know people who prefer the 732A over the 732B because of this. The only problem with the 732A is that the heaters use more power than the 732Bs. Early manuals spec 24 hour battery operation, but later manuals have changed that to 12 hours. All of the 732As I have observed will only run for about 12 to 15 hours before the "in cal" light goes out meaning that the batteries have dropped below about 22 volts. The 732B is speced at 72 hours battery operation but I have no experience if this is true. I guess I am a real "Volt-Nut" in that I have 6 732As at home right now. I inter-compare them once a week. The last time I was able to verify what the official "volt" is was in 2005. Right now I need to find a good Cal Lab in the South SF Bay Area where I can have one of them "certified" against their traceable standards. The Fluke service center was closed years ago. Bill ___ 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] HP 3457A calibration?
I have replaced this type of battery in other equipment, so it isn't a big deal for me. I'm sure I can do it without losing the cal data. Joe Gray W5JG On Aug 20, 2013 9:43 AM, "Dr. David Kirkby" wrote: > On 20 August 2013 14:51, J. L. Trantham wrote: > > If the battery is 'OK', I would favor just sending it to Agilent for > > calibration, unless you can 'SAFELY' change the battery while preserving > the > > cal data. > > > > Good luck. > > > > Joe > > If one accepts there is some risk changing the battery while > preserving the data, one has two choices. > > 1) Do as you say and leave the battery, preserving the cal data. This > however risk the battery leaking at some time. > 2) Change the battery, losing the cal data, but virtually eliminating > the risk of leakage. > > To me at least, the path of least risk is the one to take. > > I suspect if one put a power supply in parallel with the battery with > a 10 k resistor in series, then the 10 k resistor would not drop > enough voltage to lose the ram data, but if it was accidently shorted > the current would be limited to a few hundred microamps. That's > unlikely to do any damage > > I guess for a volt nut, preserving the cal data is more important than > it is to me. Not damaging the meter is higher on my priority list. > > 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.
Re: [volt-nuts] HP 3457A calibration?
Op 20-8-2013 7:39, Dr. David Kirkby schreef: A bit of a silly video IMHO. I can't take anyone seriously who measures the noise on a 6.5 digit multimeter by looking at the digits which change as it is across his standard bench power supply. Personally I would have thought one measured the stability of the bench supply by measuring with the DVM rather than the other way around Not only that, the guy obviously doesn't even know how the thing works, based on his 'explanation' of integration time. Good video for when I can't get to sleep, though ___ 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] HP 3457A calibration?
On 20 August 2013 14:51, J. L. Trantham wrote: > If the battery is 'OK', I would favor just sending it to Agilent for > calibration, unless you can 'SAFELY' change the battery while preserving the > cal data. > > Good luck. > > Joe If one accepts there is some risk changing the battery while preserving the data, one has two choices. 1) Do as you say and leave the battery, preserving the cal data. This however risk the battery leaking at some time. 2) Change the battery, losing the cal data, but virtually eliminating the risk of leakage. To me at least, the path of least risk is the one to take. I suspect if one put a power supply in parallel with the battery with a 10 k resistor in series, then the 10 k resistor would not drop enough voltage to lose the ram data, but if it was accidently shorted the current would be limited to a few hundred microamps. That's unlikely to do any damage I guess for a volt nut, preserving the cal data is more important than it is to me. Not damaging the meter is higher on my priority list. 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] HP 3457A calibration?
Joe, You might start with just measuring the battery voltage. There are two different batteries used in the 3457A, one that is obsolete and the other still obtainable. Per the manual, there are two resistors that need to be changed if switching from the 'obsolete' battery to the 'new battery'. However, I wonder if the resistors even need to be changed. See message #48954 in the archives and the several messages surrounding that. If the battery is 'OK', I would favor just sending it to Agilent for calibration, unless you can 'SAFELY' change the battery while preserving the cal data. Good luck. Joe -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Joseph Gray Sent: Monday, August 19, 2013 10:16 PM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP 3457A calibration? Someone pointed out in the comments that his DMM was probably calibrated once or twice at the most. >From looking at what is on this guys shelf, he has way more money than I do to spend on test equipment. I'm jealous :-) Speaking of too much test equipment, that guy Dave who does the EEVBlog videos also has a lab to drool over. I don't know what he does for a living, but he seems to be more knowledgeable than the guy from South Africa (who is also long winded and boring). As for the "cheaper" solution, I just bought a 3457A. I expect to see it this week. After checking it out for a bit, I'll be sending it to Agilent. Although it may seem ridiculous to spend $200 getting it calibrated, I figure that I'd be better off having Agilent do it this time, so I know where I stand. I'll have to read the cal counter before and after sending it to Agilent. I'll let you know the results. If the battery looks original, I'll have to change that out before sending it for calibration. I know that I have to keep the SRAM powered, so I don't loose the data already there. Joe Gray W5JG On Mon, Aug 19, 2013 at 7:59 PM, J. L. Trantham wrote: > Interesting video. > > His 'cal certificate' shows no data other than 'in tolerance' and the > 'standards' used to established that. > > He also makes a point of the 'calibration counter'. > > On the 3458A that I was able to 'kill' the 'cal RAM', the 'cal > counter' was at '1' when I received it. When I finished doing my > 'home cal' on a 'blank' > 'cal RAM', the 'cal counter' was about 20 or so. It appears that > every measurement that is calibrated increments the 'cal counter'. > > I don't recall how many ranges the 3457A has but add them all up and > that is what I would expect the 'cal counter' to increment by once you > finish a 'home cal'. > > Since Agilent does all this via HPIB (at least that's what I think), > it increments the 'cal counter' only by '1' step. > > I would opt for a 'cheaper' 'seems to be working' 3457A then send it > to Agilent for their calibration rather than spend extra for someone > else's calibration. > > Joe > WB4BPP > > -Original Message- > From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] > On Behalf Of Joseph Gray > Sent: Monday, August 19, 2013 8:20 PM > To: Discussion of precise voltage measurement > Subject: [volt-nuts] HP 3457A calibration? > > Recently, we were discussing where to get a DMM calibrated. Someone > mentioned an ebay seller in Albuquerque who had their meters > calibrated across town by a company with a similar name. > > I am currently watching a YouTube video about the HP 3457A. At around > 7 minutes, take a look at the calibration certificate when he holds it up. > > http://www.youtube.com/watch?v=HfxpJCdgVwc > > 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. ___ 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] HP 3457A calibration?
I would agree, the point of keeping the cal data intact is the ability to tell if the unit is 'in tolerance' on arrival at Agilent, useful information about the 'quality/stability' of the meter, I think. Also, the 'cal number' is stored in the 'cal RAM'. If you send the 3457A in with no cal data stored and it comes back with a 'cal number' of '1', I guess you also get the answer to the question of how the 'cal number' increments after a visit to Agilent. Is there a 'cal number' stored in other 34xxA DMM's? 3478A for instance? Joe -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Dr. David Kirkby Sent: Tuesday, August 20, 2013 12:39 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP 3457A calibration? On 20 August 2013 02:59, J. L. Trantham wrote: > Interesting video. A bit of a silly video IMHO. I can't take anyone seriously who measures the noise on a 6.5 digit multimeter by looking at the digits which change as it is across his standard bench power supply. Personally I would have thought one measured the stability of the bench supply by measuring with the DVM rather than the other way around > On the 3458A that I was able to 'kill' the 'cal RAM', the 'cal > counter' was at '1' when I received it. When I finished doing my 'home cal' on a 'blank' > 'cal RAM', the 'cal counter' was about 20 or so. It appears that > every measurement that is calibrated increments the 'cal counter'. I was thinking about that cal ram, and the issues changing the battery. If one intends sending the meter away for cal, is there any point in worrying about if the ram is kept alive? I guess it might be nice to know the performance before it was calibrated as Agilent will give you, but there is a bit of a risk of damaging chaning the battery live. I intend changing the battery in mine then sending it for cal. 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.
Re: [volt-nuts] Fluke 732B
Joseph Gray writes: > There was a very interesting teardown of a 732B on the EEVBlog forum. I > downloaded the service manual, but it seems that the details on the voltge > reference section is missing. Does anyone have a full schematic of the > voltage reference? > > Teardown is here: > > http://www.eevblog.com/forum/testgear/fluke-732b-dc-standard-teardown/ Wow, nice stuff. (And so that is where all the volt-nuts traffic has gone, great thread). -- John Devereux ___ 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] HP 3457A calibration?
On 20 August 2013 02:59, J. L. Trantham wrote: > Interesting video. A bit of a silly video IMHO. I can't take anyone seriously who measures the noise on a 6.5 digit multimeter by looking at the digits which change as it is across his standard bench power supply. Personally I would have thought one measured the stability of the bench supply by measuring with the DVM rather than the other way around > On the 3458A that I was able to 'kill' the 'cal RAM', the 'cal counter' was > at '1' when I received it. When I finished doing my 'home cal' on a 'blank' > 'cal RAM', the 'cal counter' was about 20 or so. It appears that every > measurement that is calibrated increments the 'cal counter'. I was thinking about that cal ram, and the issues changing the battery. If one intends sending the meter away for cal, is there any point in worrying about if the ram is kept alive? I guess it might be nice to know the performance before it was calibrated as Agilent will give you, but there is a bit of a risk of damaging chaning the battery live. I intend changing the battery in mine then sending it for cal. 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.
