which oscilloscope

[yanmar]

Hi All,

I am looking  for oscilloscope to buy now and discover huge variety of options. I want to check for trigger errors and resets appearing on Megatune,to play with the knock sensors and to check for noise. It seems that the USB oscilloscope is the best value for money. Do you think any of these is good enough for me?

Hantek DSO-2090 - Chinese brand   -120euro
Syscomp CGR-101- many functions  -180$
UsbScope.eu       - 40kHz, but 10bit - 35GBP
Picoscope2203     -  Most reviewed  - 290E

Or to go for automotive Picoscope 4000 what they suggest which is very expensive?

Cheers

[rob@vems.co.uk]

I use the Stingray on here: http://www.easysync.co.uk/index.html?lang=en-uk&target=d16.html

[ryniobl]

Hi.I have Hantek and this one -> http://www.poscope.com/product.php?pid=18
Hantek is very nice but have no recorder... ,and PoScope has many functions but software is problem.
Get PicoScope if You have no money issues

SysComp and USBScope ,as they are pretty similar to programs that use soundcard.

If You want something really cheap that use sound card, You can try this one -> http://www.zeitnitz.de/Christian/scope_en
This one You can use as a knock detector ,because it have bandpass filter built in
Cheers

[rob@vems.co.uk]

For knock detection you can use the sound app Audacity with a bandpass filter - and a bosch knock sensor.

[MWfire]

i have dso2150, very good scope.

[ryniobl]

For knock detection you can use the sound app Audacity with a bandpass filter - and a bosch knock sensor.

Rob.Is this possible to run Audacity with bandpass filter in realtime mode?I couldn't make it...

[rob@vems.co.uk]

Using the FFT?  I've done it myself when I was testing the theory.

[z0tya]

I am using Multi Instrument for knock spectrum analisys. It has a great 3d mode!
http://www.virtins.com/
It has built in driver some of pc scope too.

[yanmar]

Thanks for the info!
I didn't pay attention that Hantek do not have recording as I need such a function to catch random signals.

I read this article on autospeed:
http://autospeed.com/cms/title_Using-Oscilloscopes-on-Cars-Part-2/A_109872/article.html
but looks like 8-bits are enough for our purpose.

Which is the maximum frequency I can expect to find out if there is noise in the system?

[rob@vems.co.uk]

Well you can work out the frequency using the equation:  kF = 900/(pi*r) where r is the piston radius.
Its worth looking at the first and possibly the second harmonic frequencies too 1st = kF x 2 and 2nd = kF x 3

[ryniobl]

Yanmar.Be very careful when you measure signals such a dwell or injector opening time.NEVER leave your laptop connected to both vems and oscilloscope! I have burned motherboard in my lap and usb chip in oscilloscope due to power ground loop. 
Of course You can use fiber optic usb extension to avoid it,but it's expensive.

[dnb]

Well you can work out the frequency using the equation:  kF = 900/(pi*r) where r is the piston radius.
Its worth looking at the first and possibly the second harmonic frequencies too 1st = kF x 2 and 2nd = kF x 3

You'll need 10 times the bandwidth of the signal you're trying to look at in order for it to not have high frequency components zapped by the anti-aliasing filter.

[yanmar]

I found a way how to use Audacity and to listen real time.

  If you don't see a mic volume control in the main mixer, in the Volume Control window, choose Options - Properties, click on  Microphone to make a check mark appear - after the the Mic Volume will appear in the mixer settings.Unmute it and have fun.

I read there is program to video datalog screen, which could be good if Megatune and Audacity are started and listen for knock at the same time. Let's see if I can find it.