Frequency Response Analyzer with Bode Plots

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Martyn
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Re: Frequency Response Analyzer with Bode Plots

Post by Martyn » Fri Apr 19, 2019 6:59 am

Which 3000 series model do you have?

If you open the PicoScope 6 software and send the info from the Help->About box that will give the required information.
Martyn
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_Wim_
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Re: Frequency Response Analyzer with Bode Plots

Post by _Wim_ » Fri Apr 26, 2019 6:13 pm

Just a quick update with some bugfixes:
- incorrect phase was shown in impedance plot (both plot and cursor)
- app did not work on X64 systems (had to force 32 bit mode for the app to make it work).

@Kai, I am still planning to do the calibration, just a bit tied up for the moment, so only had time for these quick fixes so far.
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ImpedanceViewer1012.zip
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vahid1661
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Power Measurement/Calculation using FRA

Post by vahid1661 » Tue Apr 30, 2019 12:27 pm

Hi all,

I need to measure the consumption power for a coil and a piezo. What is the standard way of doing this using FRA?

Thanks,
Vahid

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Re: Power Measurement/Calculation using FRA

Post by _Wim_ » Wed May 01, 2019 6:34 am

vahid1661 wrote:
Tue Apr 30, 2019 12:27 pm
Hi all,

I need to measure the consumption power for a coil and a piezo. What is the standard way of doing this using FRA?

Thanks,
Vahid
You mean expected power consumption at each frequency? If yes, I think the easiest way is to plot the impedance curve by using a series resistance and my impedance viewer app, export this impedance data to excel, and calculate power from there.

If you want to measure consumed power of a period of time (independent of frequency), then something like the Picolog software seems more appropriate were one channel measures the rms current (with a current probe) and another channel the rms voltage. I believe you can add a calculated channel also to display the power directly. But this way it is not possible to differentiate between real and apparent power (no phase info) .

vahid1661
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Re: Frequency Response Analyzer with Bode Plots

Post by vahid1661 » Thu May 02, 2019 1:26 am

Thanks for your reply.

What is "my impedance viewer app"?
How can I download it?

Thanks,

Vahid

_Wim_
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Re: Frequency Response Analyzer with Bode Plots

Post by _Wim_ » Thu May 02, 2019 5:38 pm

vahid1661 wrote:
Thu May 02, 2019 1:26 am
What is "my impedance viewer app"?
How can I download it?
You can find it here:
topic14311.html?&p=141799#p141728

Source code is available here:
https://github.com/WimHuyghe/FRA-Impedance-Viewer

Some more details are described earlier in this thread and here:
https://www.eevblog.com/forum/testgear/ ... plot-data/

Hans Polak
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Re: Frequency Response Analyzer with Bode Plots

Post by Hans Polak » Tue May 14, 2019 6:47 pm

Hi Aaron,

Thank you for the wonderful job you did with FRA4PS.
The more I use it, the more I like it, however concerning noise suppression I have a few questions.
With my 5243B I already use the "noise reject" option which was already a big step forward.
1) I can also choose a "noise reject bandwidth" although results with 100Hz are sometines better as with 10Hz, something that I cannot understand so well.
2) Then there is a "low noise oversampling" whose function is not at all clear, just as "noise reject timebase" and the "purity lower limit".

Maybe it's all to be found in your source code, but that's not exactly my beer.
To get the lowest possible noise in my images, I would be very grateful if you could give any further detail information on these adjustable parameters.

Kindest Regards,
Hans

hexamer
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Re: Frequency Response Analyzer with Bode Plots

Post by hexamer » Sat May 18, 2019 2:20 pm

Barnett wrote:
Wed Apr 17, 2019 7:16 pm
Hello Aaron,
It has been a while. I am back in the power supply mode. When we last spoke I was working with version 0.6.1b. I just installed your version 0.6.2b RC4. Could you tell me some of the changes in this latest version. I have a 2208B USB Pico Scope. Thanks / Charles
Hi Charles,

It's mostly bug fixes. The only features added between those versions are:

1) Ability to program a dc offset for the AWG
2) API trace logging to help diagnose issues
3) Support for 5000D series scopes

As far as I can tell none of these affect your scope or the work you're doing, so it's up to you whether you want to bother updating.

Thanks,

Aaron.

hexamer
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Re: Frequency Response Analyzer with Bode Plots

Post by hexamer » Sat May 18, 2019 2:44 pm

Hans Polak wrote:
Tue May 14, 2019 6:47 pm
Hi Aaron,

Thank you for the wonderful job you did with FRA4PS.
The more I use it, the more I like it, however concerning noise suppression I have a few questions.
With my 5243B I already use the "noise reject" option which was already a big step forward.
1) I can also choose a "noise reject bandwidth" although results with 100Hz are sometines better as with 10Hz, something that I cannot understand so well.
2) Then there is a "low noise oversampling" whose function is not at all clear, just as "noise reject timebase" and the "purity lower limit".

Maybe it's all to be found in your source code, but that's not exactly my beer.
To get the lowest possible noise in my images, I would be very grateful if you could give any further detail information on these adjustable parameters.

Kindest Regards,
Hans
Thank you for the feedback, Hans.

A few posts ago, I had tried to clarify many of these. You might find some useful explanation here: topic14311-255.html#p121551

Some additional clarifying details for your questions:

1) "low noise oversampling" does not apply to noise reject mode
2) "purity lower limit" is not implemented yet. Purity is a measure of the energy detected by the DFT vs total signal energy (excluding dc energy). Once implemented, the concept is that if the purity measure is too low, additional mitigations could be activated: retrying, increasing the stimulus signal, etc. Purity is computed now, but is only reported in time domain diagnostic plots.

As for why you sometimes experience more noisy results with narrower bandwidth, I wonder if it's because of some of the more recent discussions here regarding DDS implementation. You could try the "extra settling time" option to determine that. You could also turn on time domain diagnostic plots to visualize what noise source is present.

Thanks,

Aaron.

kirankanchi
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Re: Frequency Response Analyzer with Bode Plots

Post by kirankanchi » Mon May 20, 2019 5:55 am

Hello,
I have a PICOSCOPE 5444B and 2207B, FRA works like a charm on the 2207B but limited to 1Mhz. Can this limit be lifted ? what are the limiting factors ? I am sorry for my ignorance, i am new here .

I tried with FRA with my PICO 5444B but i get error : Error: Unable to initialize device with serial number FX923/063.

Is the max frequency limit going to increase with 5000 series ?

Kudos for the tool!

Thanks
Regards
Kiran Kanchi.

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