The history of development of HP 34401a - Page 1
Forum section: electronics / general

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 18, 2022, 10:59:11 am
content: Hello!I'm just interested in how was the famous multimeter made... I looked atwww.hpmemoryproject.combut there is no any related information... I like very vell that DMM and I would want to know who and how made it many years ago... Maybe there are some pictures: develop team, prototypes of PCB and so on...P.S. Sorry for my english, I haven't practice in writing some time...

author: alm
author_rank: Super Contributor
timestamp: May 18, 2022, 01:47:03 pm
content: See if you can find a HP Journal article about it. Figure out when it first came out, and read HP journal issues from around that date. It came out in the time that HP started to become less open about the technology behind their products, so I don't know if there is one and how much detail it would contain.The HP 3457A and 3468A/3478A might be considered as its predecessors.

author: Grandchuck
author_rank: Super Contributor
timestamp: May 18, 2022, 02:28:06 pm
content: Here is some info:https://www.deepdyve.com/lp/emerald-publishing/delivering-the-promise-B6HUmrHczD

author: Keith956
author_rank: Regular Contributor
timestamp: May 18, 2022, 08:33:32 pm
content: Quote from: Grandchuck on May 18, 2022, 02:28:06 pmHidden behind paywall...

author: KE5FX
author_rank: Super Contributor
timestamp: May 18, 2022, 08:49:47 pm
content: Ad majorem Sci-Hub gloriam.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 19, 2022, 12:34:09 am
content: Quote from: KE5FX on May 18, 2022, 08:49:47 pmOh yes! This service is fantastic!Thank you a lot for the article!!! It's very interesting!

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 19, 2022, 09:27:31 am
content: Hello,the 34401A is derived from the 3458A, especially concerning its A/D Multislope III.Probably the 3458A R&D team directly transferred their ideas into the 34401A design.It also came on the market soon after the 3458A, in 1991, I think. My privately acquired unit is from 1992, and still working properly.As far as I remember, several remainder of the the 3458A R&D team also designed the 34465/470A, about 25years later, and then retired afterwards.I assume, that there is no big expertise left over @ KS to invent / develop the next innovative generation of DMMs.Frank

author: HighVoltage
author_rank: Super Contributor
timestamp: May 19, 2022, 12:01:18 pm
content: Yes, allegedly many of the original 34401A designers were pulled out of retirement and helped with the design of the new generation, starting with the 34461A.This attached picture of the 34461A design team was published, when the new meter came on the market.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 20, 2022, 01:01:01 pm
content: Hello, Dr. Frank!I read much about HP 3458 in HP Journal. What about ADC they are different in hardware, however the algorithm is almost the same. And the ADC in HP 34401a I like a little more... I don't know why...Excuse me, you mean that there aren't experts at Keysight to develop new DMM? Then how the're developing other instruments? Are they (the instruments) simpler than DMM?)))HighVoltage, thank you very much for the picture! It's nice to meet them))

author: Dr. Frank
author_rank: Super Contributor
timestamp: May 20, 2022, 01:54:22 pm
content: Quote from: MrYakimovYA on May 20, 2022, 01:01:01 pmIn a recent product presentation about the 34401As multislope III A/D, I remember to have read exactly that, i.e. simplified HW, same state machine principle like the 3458A. I don't find this presentation any more, maybe it is inside the old manuals.Me and some of other volt-nuts in this forum followed closely the development, or better the changes due to bugs of the 3446x platform, especially the 465/470A ones. See former analysis of the 465A/470A in another thread. Therefore we came to know that several of the old 3458A designers were involved, and that they either retired, or went to Keithley.The R&D story behind the 3458A BE is also known in parts.. why and how there was no deep redesign, and probably will not happen any more in the future.The design of such an instrument (DMM) is also very complicated, mostly analogue magic, don't underestimate this, and do not compare that with those RF designs, which are a completely different kind of magic.Good analogue designers are getting more and more rare, I fear.RF designers will not necessarily have the wisdom to design good DMMs.The most important business for KS are scopes, and so, especially margin-wise.Just watch the current Keysight Live Lab, what products they promote the most.Frank

author: Kleinstein
author_rank: Super Contributor
timestamp: May 20, 2022, 06:18:42 pm
content: The front end of the 34401 is still relatively similar to the 3478 / 3457, with most of the switching in a hybrid with rather similar function, just good for 10 V at the input instead of 3 V.The ADC is a kind of novelty - not a big step forward in performance, but relatively low cost and protected by a then new patent.There are mainly 2 good points about the ADC in the 34401: it is relatively low cost (avoid selected/matched JFETs), though it still uses an ASIC and the INL is relatively good. Noise and resolution (especially for faster conversions like 1 PLC) are not especially good.The big point was more like a cheaper alternative to the 3457 and getting a 10 V prime range and no longer the odd 3 V of the 3457.The odd part is that the ADC in the 3457 is good for 10 V, while the MS3 ADC would work more naturally and better with a 3 V input range.Looks a little like they had a 3 V range in mind when they designed the ADC.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 21, 2022, 02:50:44 pm
content: So if Keysight is now scope expert what's LeCroy is going to do? Two big scope developers... who bill be acquired first by another?Ok, I'll look at the thread about 465A/470A. I know about only bug that made it impossible to measure above 700 VDC and 400 VAC. I don't remeber the exact numbers. This was disscussed somewhere in the forum.And who is the DMM leader developer now? The Keithley is acquinted by Tektronix. Maybe Fluke?

author: nightfire
author_rank: Frequent Contributor
timestamp: May 21, 2022, 03:16:59 pm
content: Are Fluke, Keithley and Tektronix not hold together by Danaher/Fortive? So basically they are in the same boat...

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 22, 2022, 01:33:23 am
content: Quote from: nightfire on May 21, 2022, 03:16:59 pmOh! That's news to me! So, they are!

author: JohanH
author_rank: Frequent Contributor
timestamp: May 27, 2022, 09:09:43 am
content: It's a shame there is no centralized information about this meter. It really should have at least a wikipedia page or something. There is a ton of information in various places.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 27, 2022, 02:07:46 pm
content: Quote from: JohanH on May 27, 2022, 09:09:43 amIndeed! The DMM is the milestone! It should be describerd in detail as much as it possible! Peope must know everything about it!

author: alm
author_rank: Super Contributor
timestamp: May 27, 2022, 03:24:44 pm
content: There's aTekWikito collect information on old Tektronix equipment, but I'm not aware of a similarly popular resource for HP/Agilent or any other test equipment brand.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: May 28, 2022, 01:28:54 am
content: Quote from: JohanH on May 27, 2022, 09:09:43 amGo on Wikipedia and start your own page. I did that.

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 28, 2022, 01:33:24 am
content: Quote from: alm on May 27, 2022, 03:24:44 pmI know only this one:https://www.hpmemoryproject.org/

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: May 28, 2022, 01:50:37 am
content: There were wildfires in Santa Rosa a few years back that destroyed or at least partially damaged the archives of keysight/Agilent.https://www.theregister.com/2017/10/29/hewlett_packard_history_lost_to_santa_rosa_fires/

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 28, 2022, 02:16:10 am
content: Quote from: chickenHeadKnob on May 28, 2022, 01:50:37 amIt's so sory to hear that. Who lit the bonfire and forget to shut it off? The whole story (most part at least) of the greatest company was destroyed. HP/Agilent were always some sort of inspiration to me! Nice equipment! Great open service manuals with a little theory, circuit diagrams, drawings and so on. Their beautiful HP Journal was fine addition to all!

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: May 28, 2022, 03:27:03 am
content: Quote from: MrYakimovYA on May 28, 2022, 02:16:10 amBig wild fires happen in Southern California all the time. Some caused by people, intentional arson, some caused by power lines, sometimes it is lightning. It is like a disaster zone there.

author: free_electron
author_rank: Super Contributor
timestamp: May 28, 2022, 04:59:19 am
content: Quote from: chickenHeadKnob on May 28, 2022, 03:27:03 amdon't forget the shake-rattle-n-roll. California is gods etch-a-sketch.you get used to it.4.0. meh , don't bother getting up5.0 careful not to spill the whiskey while pouring6.0 maybe we should get drinks outside.

author: mawyatt
author_rank: Super Contributor
timestamp: May 30, 2022, 01:23:49 pm
content: Keysight's CTO, Jay A lost his home to the Santa Rosa fires, so did Keysight Technical Fellow Tim S. The fires spared most of the Santa Rosa facility, however the nice 1960s style motel down the street (can't recall the name) we stayed when visiting didn't survive.The old HP and Tektronix manuals were technical novels, unfortunately long since forgotten as we don't see these anymoreBest,

author: RoGeorge
author_rank: Super Contributor
timestamp: May 30, 2022, 02:13:08 pm
content: HP archives and Tektronix manuals are still around, read and referenced quite often in this forum.A collection of links to find most of them for free:https://www.eevblog.com/forum/projects/found-a-goldmine-looking-for-more-treasures-(hp-journal-and-alike)/

author: MrYakimovYA
author_rank: Regular Contributor
timestamp: May 30, 2022, 02:53:31 pm
content: Quote from: RoGeorge on May 30, 2022, 02:13:08 pmHi RoGeorge,that's amazing! I'm going to closely look at every link listed in that thread! Thank you!!!

author: RoGeorge
author_rank: Super Contributor
timestamp: May 30, 2022, 08:24:26 pm
content: Glad you find those interesting. Many are very well written and still actual. Other are full nostalgia.Either way, it's a lot to enjoy reading for years.