Hi ,

I have just got hold of a 2 channel pico scope and was doing some tests to see how the scope is.
I have attached a screen shot of the waveform ,it's a primary ignition current (waste spark coil ) can anyone tell me why the middle of the ramp curves up then down ? car runs fine ..Is this ramp normal ?
Also have done a camshaft sensor test ...why does the square wave have the curves at the end are these a ground issue  or normal noise   ?

Thanks

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Anyone any ideas as to why the wave forms  have that spike on the ignition coil current and the the cam sensor  curves after the trailing edge?

which model scope ?
where are you coupled for the CMP sensor ?
include primary voltage with the coil current & repost.

+ car details ?

Hi it's an old model 3223 2 channel   ...cam sensor  probes   connected signal wire of cam and negative lead to battery ground.Current clamp was connected close to ignition coil feed .car is a 1.6  petrol  vauxhall astra G  2003  z16se.

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second image posted is the original file as in previous post..  Car runs fine..just wanting to know that the scope is fine as only just got it.Did injector voltage and current wave form and they look   OK .Just not sure about the images  i posted.

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scopeman wrote on Aug 10^th, 2016 at 11:02am:

just wanting to know that the scope is fine as only just got it.

I don't see anything there that would make me suspect you have a scope problem.

The first image looks like you may have more than one component down the line from your current probe test point.

The second one looks like voltage drops caused by the coil current loads.

Tom Roberts wrote on Aug 11^th, 2016 at 8:32am:

scopeman wrote on Aug 10th, 2016 at 11:02am: just wanting to know that the scope is fine as only just got it. I don't see anything there that would make me suspect you have a scope problem. The first image looks like you may have more than one component down the line from your current probe test point. The second one looks like voltage drops caused by the coil current loads.

Hi Thanks Tom for the reply.I changed  the usb lead and re scoped the cam and coil  today.Both wave forms look good now  so hopefully resolved.Attached new files below.

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scopeman wrote on Aug 11^th, 2016 at 9:32am:

I changed  the usb lead and re scoped the cam and coil

I can't explain that.  Makes no sense to me.  I suspect something else changed as well.

Tom Roberts wrote on Aug 11^th, 2016 at 10:12am:

scopeman wrote on Aug 11th, 2016 at 9:32am: I changed  the usb lead and re scoped the cam and coil I can't explain that.  Makes no sense to me.  I suspect something else changed as well.

This is what baffled me as i connected everything the same way with same settings but different usb lead .Could be that the other usb lead was intermittent  as scope was on front passenger seat with my laptop? not really sure  but like i said as soon as i set up this morning i got the waveforms without any problems.What do you think could have changed as leads and clamp were in same position as yesterday and used same pre set settings on the scope.Will be trying some more tests tomorrow if weather persists.

Well , have been testing today and i now know that the usb lead is intermittent as i used the old one and after wiggling it some of the signals  were  acting up  so swapped back to the good one and all was fine.Also i experimented with moving the leads closer to other components and got some interference when doing so,so  i might not have put the leads in the exact same position when i tested .  Seems the usb cable may have masked other issues  . Just glad the scope is fine and working . ;)

While on this thread does anyone know how to be able to open  the compression test files.I I did the test today but cannot open the file ,it says pddata?

scopeman wrote on Aug 12^th, 2016 at 10:16am:

While on this thread does anyone know how to be able to open  the compression test files.I I did the test today but cannot open the file ,it says pddata?

Are you attempting to open it with PicoScope 6?  pddata files are for Pico Diagnostics.  It's easiest to open PD and click 'load' from the File menu.

Andrew Phoenix wrote on Aug 12^th, 2016 at 12:46pm:

scopeman wrote on Aug 12th, 2016 at 10:16am: While on this thread does anyone know how to be able to open  the compression test files.I I did the test today but cannot open the file ,it says pddata? Are you attempting to open it with PicoScope 6?  pddata files are for Pico Diagnostics.  It's easiest to open PD and click 'load' from the File menu.

Hi yes i i have  tried to open it with pico 6 and also with the pico diagnostics that i downloaded to do the test with. . This is the error i get " value cannot be null.parameter name.source"