4425 and API cannot get it going

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liviu2004
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4425 and API cannot get it going

Post by liviu2004 »

It might not look like from the title, but one would ask, why we don't use big data on automotive as well?

I'm trying to get my 4425 going with the provided example ps4000.xlsm.
All dlls from SDK PicoSDK_32_10.7.21.227 are in the C:\Windows\System 32.

Windows 7 x64 laptop, with usb 2.0.

I can't seem to get a connection with the oscilloscope and running any macro will freeze excel. See also print screen, where scope details are not shown before freezing.

Debug seems to show cycling of:
While IsReady(handle) = 0
Sleep (5)
Wend

Need someone to kick my butt so I can move forward.
Attachments
ps4000.xlsm
(41.36 KiB) Downloaded 124 times
freeze.png

ben.martins
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Re: 4425 and API cannot get it going

Post by ben.martins »

Hi Liviu,

Hope all is well with you?

I think it might be best if you email into support@picotech.com. The team there will be able to better assist you with SDK support.

Kind regards

Ben

liviu2004
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Re: 4425 and API cannot get it going

Post by liviu2004 »

Hi Ben, support was kind to guide me to the ps4000a.xlsm, which worked indeed. I'm ok so far, many thanks, hope you as well.

Took me forever to get to this point, but I'm not done yet, I want to add a cyl sync as well.

Have you noted that missing 2 teeth not a problem anymore? :D
Attachments
2022-03-07_20-53-45.png

ben.martins
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Re: 4425 and API cannot get it going

Post by ben.martins »

Hi Liviu,

Thanks for letting me know and all is well here thank you.

Great work on the work you are doing so far and really intrigued as to how far you will take it. Look forward to seeing the next version!!

Kind regards

Ben

liviu2004
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Re: 4425 and API cannot get it going

Post by liviu2004 »

Hi Ben,

Now at version 564 and a covid later, update log shows:

- added channel B to include ignition coil cylinder 1 (not live tested yet)
- collect from channel B, ignition time when voltage crosses threshold of 100V on rising edge
- mark cylinders 1 to 4 by dividing the time equally (I know, not 100% accurate but for what I need, close enough)
- graph engine speed and cylinders marking (excel error bars), as per photo, note again, ignition is not live tested, I just used some points in order to make the VBA working
- added cylinder labels to ignition marks (don't look left side of graph, I selected timing points too close just to see how VBA works).

Its all a pain to do in excel vba also while learning it, but figuring out the basics, I want to learn python and do this live visualization.
Attachments
version 564.PNG

liviu2004
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Re: 4425 and API cannot get it going

Post by liviu2004 »

It's finally done. Code is rough, excel is slow, but hey, it's working.
Did a test with all cylinders running normal, and another test with injector 1 disabled.
Just two buttons, one Get Data and one Process Data and all the magic is done by Visual Basic code.

https://youtu.be/f2GUuJ23POE
Attachments
with misfire.JPG
no misfire.JPG

liviu2004
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Re: 4425 and API cannot get it going

Post by liviu2004 »

Few more corrections done in VB for the following:
- correct time stamp collection at 0 crossing, it was 3 rows too early done
- reduce voltage threshold detection for ignition coil to 70V, as sometimes misses if threshold set to 100V. Attenuation 10:1 is used.
- improve processing data time by 50% by looking into the actual number of rows with data and not the entire 65000

Found that if I don't adjust the time base to match the rpm somehow, I get VB errors. Something to think about how to select time base based on user input of expected rpm. Should be possible.

Tested with cyl 4 injector wiring removed, with the automatic gearbox in D, and rpm raised to about 1400 rpm.

It works so far.
Attachments
misfire cyl 4 load 1400 rpm.JPG

liviu2004
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Re: 4425 and API cannot get it going

Post by liviu2004 »

Another update to cover the followings:
- collect rpm at ignition time
- collect rpm at 90 degrees after TDC
- compare the two values and determine if there was a misfire
- add the misfire to the respective cylinder misfire counter
- display which cylinder misfired and how many times.

Limitations: misfire detection is very simple, does not take into account transient conditions, like rpm going down or even up, I simply have no room in 65000 rows to account for an speed average 720 degrees before ignition time. Real time applications in ecus do that, such that no false misfires are noted.

https://youtu.be/qA8nB2tR7U4
Attachments
misfire counter.JPG

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