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Automotive kit

Which product is right for your exact requirements

Automotive kit

Postby Amsterdam » Sun Mar 28, 2004 9:13 am

Hallo,I had a look at the specs on the automotive scope (kit).It seems a very usefull tool.But I have a reservation with regards to its sampling speed(3Ks/sec).This seems rather slow compared with another PC based automotive scope I have seen(The ATIS scope.,that has I think a rate of 100Ks/sec)And I believe when one uses 2 channels it halves per channel as well.Also the (automotive)laptop we are using at present(Escort) has a 20Ks/sec spec,and I think scopes like the Fluke or Bosch will be simular .
The way automotive technology is going,makes it very hard to choose good equipment that is going to be usefull for several years..
I think sample speed is important for us because of emission control etc.All data is going to be faster and faster.The latest O2 sensors come to mind(And we have to be able to measure them,how else can we competently test them(and other components) properly?That is what scope usage is all about most of the time for us.)These O2 sensors are apparently so fast that they can measure the changing O2 content per cycle of a 4 Cyl car at 6000revs/min.
My question is:Wouldn't you recommend a faster scope for high tech car electronic diagnostics?
I look forward to your answer on this matter,[quote][/quote]
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Real Sample Rate

Postby Autonerdz » Sun Mar 28, 2004 4:21 pm

Hi Amsterdam,

The ADC 212/3, included in the automotive kit, has a maximum speed of 3 million samples per second not 3 Ks/sec. That being said, the maximum sample rate specification has very little to do with the actual sample rates you will experience, at common automotive time bases.

I have a Fluke rated at 25Ms/sec. The 212/3 rated at 3Ms/sec is 62 times faster in normal use.

True sample rate is directly related to how many samples can be 'collected' in the memory buffer. The larger the buffer, or Record length, the more samples you have for a given sample period. Longer time bases reduce sample rate and shorter ones increase it.

You can compare scopes by dividing the number of samples collected by the time of capture in milliseconds to get the requested sample rate in KHZ. You have to know the buffer size before you can compare one digital scope to another. If the manufacturer won't give you this information, then they either don't know, or are too ashamed to tell you. Either way, it's not a good thing. Move on.

The 212/3 can collect up to 32,000 sample on one screen. The Fluke mentioned earlier only 512.

I checked the ATIS site and found no specs for that scope.

:shock:
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Postby Amsterdam » Mon Mar 29, 2004 6:37 am

Thank you very much for your info Tom.I also like to apologise because I made a mistake in my post as I put K samples down,I should have put M samples!
With kind regards, John Gijsbers for Amsterdam Cars.
Many Regards, John Gijsbers for Amsterdam Cars
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Postby Amsterdam » Mon Mar 29, 2004 9:22 am

The issue is:does the Pico automotive scope have enough buffer capacity to catch fast signals with intermittent faults so they can be captured and looked at AFTER the fault has occurred?

With kind regards, John Gijsbers for Amsterdam Cars
Many Regards, John Gijsbers for Amsterdam Cars
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Postby Autonerdz » Mon Mar 29, 2004 4:20 pm

Hi John,

The 212/3 is quite adequate for automotive use. The 32K buffer allows it to maintain robust sample rates at the longer time bases normally used in automotive application. The 12 bit vertical resolution also allows very small voltage changes to be displayed

The horizontal and vertical zoom features allow you to then zoom in and expand areas of interest to examine fine detail.

There is also a record feature that will write triggered captures to the hard drive as they are captured. The default limit is 100 screens but you can get into the software and make that larger, if you wish. The only limitation of this feature is that the screens are not seamless. There are gaps between the screens where data is not captured. It's like a motor drive camera. Not really much of an issue because you can place a relatively large amount of time on each screen.

If you desired more power than the 212/3, I would suggest the 212/50. This is a 50mhz scope with 128K buffer per channel. The sample rate is not divided when using both channels. This one is a power users dream. Even when placing 20 seconds on the screen, long runs of complex data can be captured on a single screen with all the detail needed. The new beta version of Automotive PicoScope software is now compatable with the 212/50. It's still beta and has a few bugs yet, but soon should be ready for prime time.

:shock:
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Postby Amsterdam » Tue Mar 30, 2004 6:14 am

Thank you very much for your very helpfull information Tom.
With regards, John Gijsbers for amsterdam Cars Ltd
Many Regards, John Gijsbers for Amsterdam Cars
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