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Frequency Response Analyzer with Bode Plots

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Re: Frequency Response Analyzer with Bode Plots

Postby Langston » Sun Oct 01, 2017 4:26 am

Hi Aaron:

Thank you! :) I just purchased a 5244B, my very first Pico Technology product partially because of your application, which works flawlessly on my Win7 64 bit machine. I do not have either version of SDK installed.

I'm a long time user of dual channel DFT measurement programs that divide the DUT signal by the reference output of an analyzer, so FRA was quite intuitive for me. This process of division results in amazing accuracy and is quite forgiving of imperfect amplification used to test filters and the like.

I have one question and one suggestion:

1. How can I send you some money for this amazing gift of yours?

2. In reference to impedance measurement (V/I of course), it would be very helpful to have a linear option for the Y-Axis and it would be very helpful to have a user defined "probe attenuation" field so we can enter a number for the calibration required for the shunt resistor or current transformer employed for the current sense channel.

God bless you and your precious family - Langston
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Re: Frequency Response Analyzer with Bode Plots

Postby Nicola » Mon Oct 02, 2017 12:11 pm

Hi Hexamer,
I am trying to run FRA on a 2205MSO (which is correctly seen and initialized by the application), but as soon as the scan starts it remains blocked in the first point.
When I abort the scan, I have the Fatal Error 46.
I have Win7 64bit, and I have installed 32bit SDK. FRA version 0.6.1b.

Is there something I can do to make it work?
Thanks for the hard work


Nevermind, problem solved!
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Re: Frequency Response Analyzer with Bode Plots

Postby hexamer » Tue Oct 10, 2017 3:53 am

Langston wrote:Hi Aaron:

Thank you! :) I just purchased a 5244B, my very first Pico Technology product partially because of your application, which works flawlessly on my Win7 64 bit machine. I do not have either version of SDK installed.

I'm a long time user of dual channel DFT measurement programs that divide the DUT signal by the reference output of an analyzer, so FRA was quite intuitive for me. This process of division results in amazing accuracy and is quite forgiving of imperfect amplification used to test filters and the like.

I have one question and one suggestion:

1. How can I send you some money for this amazing gift of yours?

2. In reference to impedance measurement (V/I of course), it would be very helpful to have a linear option for the Y-Axis and it would be very helpful to have a user defined "probe attenuation" field so we can enter a number for the calibration required for the shunt resistor or current transformer employed for the current sense channel.

God bless you and your precious family - Langston


Thank you for your kind words. I appreciate the offer, but am not looking for any financial support.

Those are good suggestions I can add to the list of requested enhancements. In the meanwhile, do be aware of a couple of other avenues that might help solve your need.

1) The raw output data can be exported, so you can transform and graph any way that you wish
2) There is a DLL form of the software that you could control by several means: Excel, Scripting language (e.g. Python), or your own GUI developed in whatever language you like (C++, C#, Java, etc). The Excel method would not require any significant programming efforts. In fact a major impetus for making an API version was to support someone making automated impedance measurements.
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Re: Frequency Response Analyzer with Bode Plots

Postby _Wim_ » Sun Nov 12, 2017 11:37 am

Just wanted to express my thanks for providing this app. I makes my 5442B so much more useful!
I was a bit surprised this was not included in the picoscope software. Before I purchased my picoscope, I had seen screenshots of your app, but did not realize that this was not a screenshot of an external app. Luckily google pointed me in the right direction.

Thanks again, Wim.
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Re: Frequency Response Analyzer with Bode Plots

Postby hexamer » Wed Nov 15, 2017 1:38 am

_Wim_ wrote:Just wanted to express my thanks for providing this app. I makes my 5442B so much more useful!
I was a bit surprised this was not included in the picoscope software. Before I purchased my picoscope, I had seen screenshots of your app, but did not realize that this was not a screenshot of an external app. Luckily google pointed me in the right direction.

Thanks again, Wim.


Thank you, Wim. I appreciate the kind feedback.
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Re: Frequency Response Analyzer with Bode Plots

Postby wally555 » Mon Dec 04, 2017 1:20 am

Hexamer, i wanted to thank you for your efforts to bring Bode plots to the PicoScope.

After reading this thread i did some research on signal injection transformers. Your idea of using the Jensen VB-1BB video isolator was a good one but i noticed in your thread you talked about not using all the bits of the signal generator because of the low output voltage required for the 1-1 transformer.

This web page has information on building a signal injection transformer using a current sense transformer (loads v e r y slow).

http://ele-tech.com/html/injection-volt ... lysis.html

Here are the highlights i gleamed from it.

Most of the article was about using the PE-51687 Pulse Electronics Current Sense Transformer, and showed some response curves. The other transformers were briefly mentioned.

From the schematic It looks like you should add a 50 ohm resistor across the primary, and from the article you use a 8 turn secondary.

PE-51686NL, 5 mH, ? Hz to 100 MHz, $3
PE-51687NL, 20 mH, 200 Hz to 3 MHz, using 8 turn secondary, $3.40
PE-51688NL, 80 mH, 50 Hz to ?, $3.40

For the low frequency end you need lots of inductance. The most inductance i could find in stock at DigiKey is as follows.

Triad Magnetics Current Sense Transformer

CST2063A, 130 mH, $7
CST2063T, 130 mH, $7

I do not have a PicoScope to try this but i hope someone else does and will report back.

Edit
The website i posted was a bad translation of the original article i just found from Maxim. See PDF or search for.

"Maxim AP note AN3245 Injection Transformers for Closed-Loop DC-DC"
Attachments
maxim ap note AN3245 Injection Transformers for Closed-Loop DC-DC.pdf
(183.11 KiB) Downloaded 54 times
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Re: Frequency Response Analyzer with Bode Plots

Postby hexamer » Sat Dec 09, 2017 4:05 pm

wally555 wrote:Hexamer, i wanted to thank you for your efforts to bring Bode plots to the PicoScope.

Thank you! I'm always interested in seeing how people are able to use it and improve on the process.
wally555 wrote:i noticed in your thread you talked about not using all the bits of the signal generator because of the low output voltage required for the 1-1 transformer.

If I'm understanding which topic your referring to, I may have been talking about issues related to not being able to control the input stimulus voltage because the transformers response is not perfectly flat. That issue should be less important now since the application has an adaptive stimulus mode (provided it's used of course). So, your idea to use less capable but inexpensive isolation transformers is a good one.
wally555 wrote:I do not have a PicoScope to try this but i hope someone else does and will report back.
. Since these are so inexpensive I'll probably just order some when I place my next digikey order. Can't promise when I could get around to testing them, but I do have some plans to test out more SMPS, so probably then.
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Re: Frequency Response Analyzer with Bode Plots

Postby Ian P » Mon Jan 15, 2018 11:13 am

Dear Hexamer

I was very pleased to find your FRA4 app and was looking forward to trying it out. It's exactly what I need for my projects. I have a 2206B scope.
When I tried to download it from your site Norton Security flagged it as malicious and cancelled the download :-(
I know from previous experience with Symantec and false positives that only the file owner can get it whitelisted. They did the same a while back to my favourite VPN app.
The "malicious" flag seems to be based on very low usage statistics, which are hardly surprising considering the specialist nature of the software.

In the meantime I can always disable Norton for the period of the download, although I'm always uncomfortable about doing that.
Best regards
Ian
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Re: Frequency Response Analyzer with Bode Plots

Postby Ian P » Wed Jan 17, 2018 7:09 pm

Dear Aaron Hexamer

I have now downloaded and installed FRA4 (Windows 10 Pro) and it's excellent!
Many thanks for creating it, it's just what I needed. I work mostly with amplifiers, acoustics and power supplies and having such an easy way to examine amplitude, phase and gain/phase margin is most helpful.

I didn't need SDK for it to run and it identified the 2206B no problem. I did install SDK, just in case, after I'd done a few tests, but it made no difference. I was wondering whether some of the features that didn't work were from the absence of SDK, but then I read your wiki properly and realised you intend them for future releases, listed under "planned future enhancements".

I found the explanation of Error 46 in the thread above, and as you say, it doesn't interfere with the operation of the instrument.

Many thanks for all your hard work and generosity.

Ian
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Re: Frequency Response Analyzer with Bode Plots

Postby hexamer » Wed Jan 17, 2018 11:15 pm

Ian P wrote:Dear Hexamer

I was very pleased to find your FRA4 app and was looking forward to trying it out. It's exactly what I need for my projects. I have a 2206B scope.
When I tried to download it from your site Norton Security flagged it as malicious and cancelled the download :-(
I know from previous experience with Symantec and false positives that only the file owner can get it whitelisted. They did the same a while back to my favourite VPN app.
The "malicious" flag seems to be based on very low usage statistics, which are hardly surprising considering the specialist nature of the software.

In the meantime I can always disable Norton for the period of the download, although I'm always uncomfortable about doing that.
Best regards
Ian


It's ironic that the same happens on my PC. Every time I upload the version to Bitbucket, then download and install to test the round-trip process, Norton flags it as potentially malicious, even though it came from my PC!!! I guess the antivirus can only be so smart.

The first time it happened I was worried that I unknowingly included some API call that trips its scan engine. But then I read it closer and realized it's (like you said) because of low usage stats. Thanks for pointing out that it could be white-listed. If the process is straightforward I'll try to do that.
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Re: Frequency Response Analyzer with Bode Plots

Postby hexamer » Wed Jan 17, 2018 11:18 pm

Ian P wrote:Dear Aaron Hexamer

I have now downloaded and installed FRA4 (Windows 10 Pro) and it's excellent!
Many thanks for creating it, it's just what I needed. I work mostly with amplifiers, acoustics and power supplies and having such an easy way to examine amplitude, phase and gain/phase margin is most helpful.

I didn't need SDK for it to run and it identified the 2206B no problem. I did install SDK, just in case, after I'd done a few tests, but it made no difference. I was wondering whether some of the features that didn't work were from the absence of SDK, but then I read your wiki properly and realised you intend them for future releases, listed under "planned future enhancements".

I found the explanation of Error 46 in the thread above, and as you say, it doesn't interfere with the operation of the instrument.

Many thanks for all your hard work and generosity.

Ian


You're very welcome. Thank you for your feedback. I'm happy it's useful. BTW, with regard to the Error 46 topic, the Picotech support team worked with me to help fix that problem as well as some other enhancements. I hope to post that version soon.
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