Recent Posts

1

Metrology / Re: reading Keysight 3458A serial number

« Last post by analogRF on Today at 05:49:57 pm »

do you have a cal sticker on it,  sometimes you can do a reverse search  if it was stored at the cal facility,  traceable

it only has a Electrical Safety Check sticker by Keysight from July 2023 but that does not have any work order number on it.
Cal seals on the screws are intact.

it seems to be working properly. Passed self tests and ACAL ALL at least 15 times by now. No errors but I am still not sure it is really
flawless or not.  So maybe it has a drift problem which needs long term testing? I dont know...

I am not a volt nut and never had a 3458A before and never studied about them so it's all new to me.

I am contacting the seller to see if he knows anything. I can return it if he cannot provide a reasonable answer

2

Test Equipment / Re: GW Instek MFG-2000 Newbie question

« Last post by Agosto on Today at 05:49:18 pm »

Thanks to both of you! Yes, I read the manual but while changing the load parameter I was focusing on the output and not on the generator display. So indeed the displayed value doubles in "High Z" mode.
Now: After changing the load to "High Z" generator display shows 300mV rms, output is 308mV rms. Is the accuracy appropriate for a generator in this price range?

3

Test Equipment / Re: Siglent SDS800X HD 12 bit DSO's

« Last post by temperance on Today at 05:47:16 pm »

Off topic: HP15 collectors edition. They should lower the price and force children to use RPN calculators in order to avoid those stupid PEMDAS discussions.

On topic:

On topic:

Then oscilloscope run two days and collect data... with time stamps... what value these time stamps have... ther is hours, minutes, seconds and milliseconds and even more...
If its clock drift tens of seconds... in some cases  collected data value is just  as garbage... you see events but time is more like from lottery machine than real trusted time stamper.  So, we build machine where is fine time stamping system for events but then we do not have time... oh well we have "some" time... perhaps even minute is wrong... (* look ETA)

Can you give an example of a case where something like that was required?

For a glitch which happens every now and then, I narrow down where it might occur and revert to brute force methods instead of waiting.

4

Test Equipment / Re: Hacking the Rigol DHO800/900 Scope

« Last post by Fungus on Today at 05:46:01 pm »

We don't know if it's a bug or a curiosity yet.

Getting the answer to that question is exactly why I suggested that other DHO800 owners check whether it's a systematic issue. I was not interested in a "mine is better than yours" competition -- although I am pleased enough with the result now that you asked for it.

Ok, I just hooked all four probes up to a crocodile clip coming out of my pulse generator, and... nada.

All traces line up perfectly.



Test setup:

5

Programming / Re: Show definitions + autocomplete function parameters for C (text editor over ssh)

« Last post by DiTBho on Today at 05:44:46 pm »

It does not work on FUSE or remote file systems, because they do not monitor or report changes in the remote filesystem.
It is not a limitation of inotify/fanotify; it is a limitation of those file systems.

Thanks for the clarification!
Tested before reading your answer: as expected inotifywait doesn't work on sshfs.
And It doesn't even work on experimental versions of BeFS, but I expected that. On Linux, without extra patches BeFS is RO.
No problem, I was curious about this.

6

Test Equipment / Re: GW Instek MFG-2000 Newbie question

« Last post by KungFuJosh on Today at 05:44:22 pm »

Yup, sounds like mismatched load. That will happen trying to connect any AWG to a DMM. You can test on your oscilloscope and see if it makes more sense (still needs to be properly loaded).

7

Beginners / Re: buying a oscilloscoop

« Last post by Gyro on Today at 05:42:10 pm »

When the computers and video games that you are talking about were designed, 2 channel scopes were the norm in design labs. 4 channel scopes were very expensive (eg. Tek mainframes). People also knew how to use the external trigger input on 2 channel scopes when necessary. That's not to say that a 4 channel scope isn't highly desireable, but it's not an essential. This might make your limited budget stretch further.

Another item that was very expensive back then was the Logic Analyser. These day, you can get a basic Saleae USB logic analyser clone (which works with open source Sigrok) for <$10 for the 8 bit version. Back when everything was external to the microprocessor, wider LAs were used, typically 24 bits or so. 16 bit Saleae clones or even 32 bit USB models are also pretty cheap now. The work methodology was scope to look at signal integrity/quality, setup and hold timings etc, and the LA for decoding busses and decodes. SPI, I2C etc, weren't a thing back then, so protocol decoding is less useful.

I would factor both into your budget, that might mean spending a little less on the scope, but I think you will find the combination helpful.

8

Test Equipment / Re: GW Instek MFG-2000 Newbie question

« Last post by nctnico on Today at 05:41:32 pm »

Read the manual about the load setting. This can typically be set to high-z and 50 Ohm. This setting determines the scaling of the displayed amplitude. You probably have it set to 50 Ohm load while you have a high impedance load attached.

9

Power/Renewable Energy/EV's / Re: Intelligent product of Switch Mode Power Supplies?

« Last post by Faringdon on Today at 05:41:06 pm »

Thanks, i think thats what they want, yes. Maybe its a route into the market for their huge Chinese operation?

10

General Technical Chat / Re: Proof that software as service/cloud based, will never work for long term ...

« Last post by Nominal Animal on Today at 05:37:25 pm »

There's a strong thread of IT incompetence in large organisations which has perhaps promoted the outsourcing of this technology, rather than investing internally, because that's difficult and requires a longer term vision.

Agreed.  Plus, outsourcing also provides a perfect scapegoat if the vision turns out to be crap.  That is, it is 'safer' for an executive to outsource, than to invest the same amount internally, because it is much easier to deflect blame to the vendor, than to the underlings one is in charge of.

That is not the reason. The real reason is cashflow and balance. Any money a company spends on having servers in-house is money sitting on the floor as dead weight depreciating like crazy as well. A typical company is much better off spending that money on inventory and/or people who can push out a product to earn an ROI.

No, you confuse hardware with outsourcing services and entire systems.  You don't have to have the servers in-house.  Like I said earlier, the IT devs/admins/people I know would be happy to outsource the hardware.  It is outsourcing the control that is the problem.

From a business perspective, the solution that in the long term produces the best return of investment, makes the most sense.

However, in current large organizations typical managers don't stay in the same position more than a couple of years, so anything beyond that is irrelevant to them.  What matters to them, is quick returns and being promoted before the shit hits the fan.