Cold start testing - 3423

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Cold start testing - 3423

Postby stevejcb » Fri Oct 19, 2007 9:06 am

We are currently performing cold start tests on our development equipment (diesel engines) and have been trialing the Picoscope 3423.

The scope seems to work well but we have to manually calculate RPM from the cylinder firing off the trace. Are there any plans to allow direct pickup of RPM? (ie pizoelectric pickup off injector pipe)

We have a niggle with the Picoscope R6 Automotive software where a trace splits between the 1st, 2nd or 3rd etc. waveforms in the buffer there does not seem to be any way of looking at the whole trace as one. This can make comparisons difficult when flicking back and forth between waveforms or am I missing something???
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Postby PeterF » Fri Oct 19, 2007 11:09 am

Hi,
We are looking at ways of incorporating rpm and it will come eventually. Getting it simple and foolproof is not easy.
Have you tried capturing at a slower time base for a longer period with many samples and then viewing using the magnifying tools?
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buffer

Postby Autonerdz » Fri Oct 19, 2007 3:51 pm

Steve,

What Peter said :)

The waveforms placed in the screen buffer are not seamless. They are screen shots. There are gaps between them where no data is collected.

The percentage of gap time to capture time varies on time base. The longer your screen time, the smaller the percentage.

Don't be shy with the screen time. Each one is a seamless capture. Dial up the samples to the max. For example, in streaming mode at 20s/div, you can collect over 2 million samples per channel on each of four channels on one screen. That's 3 minutes and 20 seconds. Each screen goes into the screen buffer. With these settings, the gaps between the screens account for only 1% of the total time. So, with 32 screens, you record an hour and 45 minutes capturing 99% of all the data. Never been done before.

Depending on your signal frequency, this may be too much time to maintain an adequate sample rate (10.4 KHz) but you get the idea. You can also collect 2 million samples per channel for a 2 second screen capture at 1MHz per channel. In this case your screen gaps in the screen buffer will be about 50% of total time.

Tom Roberts
(The Picotologist)
http://www.autonerdz.com
THE PicoScope Automotive Authority
In North America
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Re: buffer

Postby stevejcb » Fri Nov 02, 2007 9:51 am

Autonerdz wrote:Don't be shy with the screen time. Each one is a seamless capture. Dial up the samples to the max. For example, in streaming mode at 20s/div, you can collect over 2 million samples per channel on each of four channels on one screen. That's 3 minutes and 20 seconds. Each screen goes into the screen buffer. With these settings, the gaps between the screens account for only 1% of the total time. So, with 32 screens, you record an hour and 45 minutes capturing 99% of all the data. Never been done before.


Now the engineers are saying they have too much data - never manage to please them lol.

They now want to take out a section of the data for use in MS Excel but I can't seem to find any way of just exporting a section of the data or reducing the amount of samples from the original data so that Excel isn't overloaded with the data.

Anyone got any ideas???? Help please!!!!

(Too much data :lol: )
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Postby ziko » Wed Nov 28, 2007 10:39 am

Hi just had a thought, the latest version of Microsoft Excel has the cell number limit increased from 65k to approximately 1Million. Hope this helps.

Kind regards
Ziko

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Postby davidj » Wed Dec 05, 2007 10:58 am

Thanks Ziko, As the area of interest was all on one screen, this problem of 'too much data was resolved in part by re saving 'current' waveform rather that 'all'.
Regards,
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