Author Topic: Plagiarize Keysight b2983  (Read 3455 times)

0 Members and 1 Guest are viewing this topic.

Offline ssmsc

  • Contributor
  • Posts: 6
  • Country: cn
Plagiarize Keysight b2983
« on: August 09, 2022, 11:33:13 am »
[attachimg=3]I especially despise this kind of behavior!
« Last Edit: August 09, 2022, 11:55:34 am by ssmsc »
 
The following users thanked this post: rsjsouza, Echo88, wraper, thm_w, gamalot, bsw_m, ch_scr, syau

Offline Echo88

  • Frequent Contributor
  • **
  • Posts: 734
  • Country: ua
 

Offline ssmsc

  • Contributor
  • Posts: 6
  • Country: cn
 

Offline MegaVolt

  • Frequent Contributor
  • **
  • Posts: 744
  • Country: by
Re: Plagiarize Keysight b2983
« Reply #3 on: August 11, 2022, 09:10:15 am »
[attachimg=3]I especially despise this kind of behavior!
Where are these photos from? Is there any discussion on another forum? Or a review?
 

Offline r6502

  • Regular Contributor
  • *
  • Posts: 70
  • Country: de
Re: Plagiarize Keysight b2983
« Reply #4 on: August 11, 2022, 11:29:11 am »
hello all,

have a look here:
https://xdevs.com/review/b2987a/

Very detailed review with lots of photos. need to have equipment ;D

Guido
Science can amuse and fascinate us all, but it is engineering that changes the world - - Isaac Asimov
 

Offline MegaVolt

  • Frequent Contributor
  • **
  • Posts: 744
  • Country: by
Re: Plagiarize Keysight b2983
« Reply #5 on: August 11, 2022, 12:02:51 pm »
have a look here:
https://xdevs.com/review/b2987a/
I was interested in the review on the TH2690, whose photo is very similar to the B298xA.
 

Offline thm_w

  • Super Contributor
  • ***
  • Posts: 4425
  • Country: ca
  • Non-expert
Re: Plagiarize Keysight b2983
« Reply #6 on: August 11, 2022, 11:06:45 pm »
Rotated so its easier to compare

Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 
The following users thanked this post: Mickle T., CDN_Torsten, ssmsc

Offline alm

  • Super Contributor
  • ***
  • Posts: 1988
  • Country: 00
Re: Plagiarize Keysight b2983
« Reply #7 on: August 12, 2022, 12:19:42 am »
Interesting how Tonghui skimped on the guard ring around the (presumably very high impedance) nodes with the high value thin film resistors to the point where the ring around R103 has barely any copper around the vias. Funny how on the Tonghui board they added footprints for extra resistors in case they needed to adjust something, while Keysight probably had the resistors made to spec. It also looks like the the TH board might have fewer layers, although that could be the lighting.
 

Offline MegaVolt

  • Frequent Contributor
  • **
  • Posts: 744
  • Country: by
Re: Plagiarize Keysight b2983
« Reply #8 on: August 12, 2022, 08:32:48 am »
They replaced the main part :( The vacuum capacitor was replaced with some kind of rubbish.
 

Offline Kleinstein

  • Super Contributor
  • ***
  • Posts: 11921
  • Country: de
Re: Plagiarize Keysight b2983
« Reply #9 on: August 12, 2022, 09:05:33 am »
There is obvious similarity in the layout, but there are still differences: the Tonghui meter has 1 range less and the case / connectors are also different with inputs at the front instead of the back. 
A decade lower sensitivity also means they can get away with more.

The extra footprint for a 2nd parallel high ohms resistor is odd, expecially with the same size. It would make some sense for a different size, but not this way. For a trim a sereis resistor is there an much more conventient.

Somehow both designs do not try to really keep the critcal node compacs / small.
 

Offline thm_w

  • Super Contributor
  • ***
  • Posts: 4425
  • Country: ca
  • Non-expert
Re: Plagiarize Keysight b2983
« Reply #10 on: August 12, 2022, 09:43:49 pm »
The extra footprint for a 2nd parallel high ohms resistor is odd, expecially with the same size. It would make some sense for a different size, but not this way. For a trim a sereis resistor is there an much more conventient.

The bottom one is marked as a capacitor.
Top one I can't see.
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 

Offline Echo88

  • Frequent Contributor
  • **
  • Posts: 734
  • Country: ua
Re: Plagiarize Keysight b2983
« Reply #11 on: August 12, 2022, 09:58:32 pm »
The 3pF capacitor is a vacuum type? Do you have a partnumber/datasheet for it MegaVolt?
 

Offline thm_w

  • Super Contributor
  • ***
  • Posts: 4425
  • Country: ca
  • Non-expert
Re: Plagiarize Keysight b2983
« Reply #12 on: August 12, 2022, 10:22:35 pm »
The 3pF capacitor is a vacuum type? Do you have a partnumber/datasheet for it MegaVolt?

TiN calls it:
Quote
metal-packaged capacitor
...
hermetic gold-plated reference 3.3pF capacitor used in integrator. Together with feedback resistor this network set bandwidth limit of the current input front-end.

https://www.eevblog.com/forum/metrology/keysight-b2980a-series-electrometerpicoammeter-teardown/
https://xdevs.com/doc/HP_Agilent_Keysight/B2987A/img/bem_eaucap.jpg
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 
The following users thanked this post: MegaVolt

Offline ssmsc

  • Contributor
  • Posts: 6
  • Country: cn
Re: Plagiarize Keysight b2983
« Reply #13 on: August 14, 2022, 10:45:08 am »
Tonghui should not understand the key technology of low current measurement.
 

Offline MadTux

  • Frequent Contributor
  • **
  • Posts: 749
Re: Plagiarize Keysight b2983
« Reply #14 on: August 17, 2022, 10:22:36 pm »
Lol, still managed to clone it, even with service manuals unavailable. :-DD :-DD
Take that Keysight and anyone else with no schematics available, for making honest repairs much more difficult.
 
The following users thanked this post: ch_scr, Atomillo

Offline julian1

  • Frequent Contributor
  • **
  • Posts: 563
  • Country: au
Re: Plagiarize Keysight b2983
« Reply #15 on: August 18, 2022, 10:27:49 pm »
A comment on both boards. It is curious to see all the guarding, and cutouts, while also employing signal relays (datasheet suggests 1G insulation resistance), rather than reed relays.

Maybe the signal relay coils, and pole node, are driven by isolated/floating signal relays. The digital board of the agilent has a bunch of reed relays, so perhaps that is the strategy used. 
 

Offline bsw_m

  • Regular Contributor
  • *
  • Posts: 213
  • Country: by
Re: Plagiarize Keysight b2983
« Reply #16 on: August 19, 2022, 04:45:34 pm »
A comment on both boards. It is curious to see all the guarding, and cutouts, while also employing signal relays (datasheet suggests 1G insulation resistance), rather than reed relays.

The AGN210 series relays are adequate for the application of this device. They have an insulation resistance between open contacts > 100 PetaOhm and an insulation resistance between the coil and all shorted contacts > 100 TeraOhm. (Data from actual measurements of a certain number of these relays)
These relays also provide reliable contact for switching low currents/voltages.
The main disadvantage of these relays is the absence of an electrostatic shield between the coil and the contact groups, so that they have a very high charge injection from the control (when the relay is switched).

P.S. The Hongfa relays used in the Tonghui electrometer have comparable parameters with the Panasonic AGN210 series relays
P.P.S. For comparison, the insulation resistance between the open contacts of the electrometric reed relay TRY-204S-14 manufactured by Okita is about 2 PetaOhm
« Last Edit: August 19, 2022, 05:35:20 pm by bsw_m »
 
The following users thanked this post: Echo88, Mickle T., julian1, ch_scr, MegaVolt, maat


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf