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micro amp captures (Read 25,870 times)
john racic
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micro amp captures
Jun 10th, 2010 at 5:15pm
 
Greetings

Mike and I have been experimenting with the new K110 Autonerdz micro amp probe.  We have gotten a few really neat captures.  Since we are going to try to put the reference files here with the pictures, we will be breaking this up into a few posts.

Ever work on a Honda CRV with a wheel speed sensor code?  It's the diagnosis we hate to see.  Check the wiring (page and a half).  Replace the speed sensor.  If still there substitute known good abs control unit.  Yes, right, got one of those just hanging around.

We have been unable to get a real reading off of those magneto resistive wheel speed senosrs.

Until now!

Here's a capture froma 02 CRV. The amp rpobe was zeroed, the signal has a base current of about 9 milliamps, that goes up to about 16 milliamps.  We included the last capture where we shut it down, just to show that.

And now we know.  The speed sensor is good.  No selling the sensor and then calling the customer to say " oh, and by the way you need a control module too".

For the record, this car did not have an abs problem, it was just an opportunity for us to get a capture.

John and Mike

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anhondawss.psdata (3436 KB | )
anidle.gif (100 KB | )
anidle.gif
anspeed.gif (121 KB | )
anspeed.gif
anshutdown.gif (97 KB | )
anshutdown.gif
 
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john racic
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Re: micro amp captures
Reply #1 - Jun 10th, 2010 at 5:18pm
 
Ok, so the first thing I forgot! The new version "closes" the notes, I have to remember that!  Sorry!

A and B are hooked up normally to the 2 wires to the speed sensors, and read the voltage.  A is obviously ground, and B signal.

C is the K110 on a +- 2- milliamp scale

John and Mike
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john racic
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Re: micro amp captures
Reply #2 - Jun 10th, 2010 at 5:20pm
 
And as is probably not obvious, the first capture was taken at idle, with the wheels up in the air turning a few MPH.  The second is zoomed the same, but we ran it up to a higher speed.
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john racic
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Re: micro amp captures
Reply #3 - Jun 10th, 2010 at 5:33pm
 
Here's one that did indeed have a ABS problem.  07 Ford Escape 4WD with code for right front, and low speed abs activation when it was not supposed to activate.

A is the microprobe on 20 milliamp scale.  B and C are voltage of the 2 wires, B obviously volts and c ground.

Right here you can see what is wrong with this car!  It's there in the picture.  Ford tone rings do not have a signature mark like their CKP sensors!

Once again probe is zeroed, it has a base current of about 8 milliamps and a peak of about 13.

We cannot think of any other way to see this.  Ford lists a "mystery" tester with flashing lights, but very little info is available on that.  Perhaps someone here has seen one.

More to follow!

John and Mike
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john racic
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Re: micro amp captures
Reply #4 - Jun 10th, 2010 at 5:36pm
 
And here is the other file.  These are large, so we have to post in seperate pieces.
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Earl Davis
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Re: micro amp captures
Reply #5 - Jun 10th, 2010 at 5:40pm
 
john racic wrote on Jun 10th, 2010 at 5:20pm:
And as is probably not obvious, the first capture was taken at idle, with the wheels up in the air turning a few MPH.  The second is zoomed the same, but we ran it up to a higher speed.


Hi John,

It did take a minute before I realized that the wheel speed had increased. Nice work with this new probe, thanks for sharing.
Do you have some other uses for this probe?
What size wire will the probe fit around?

Thanks,
Earl

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john racic
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Re: micro amp captures
Reply #6 - Jun 10th, 2010 at 5:46pm
 
Ok, so then our next thought was what about using the frequency measurement channel in the new version to see what is happening.  Not really what we expected.  Apparently the measurement is very sensitive to noise, but it does provide a neat picture anyways. 

Channels are exactly the same as the previous posts, but we added D.  It is a set of leads piggybacked right onto the K110.  The glitches are, according to Tom, due to excessive sensitivity, and will be addressed as Pico perfects the frequency measurement.  But it does show the frequency.

Mike and John
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anescapewfreq.gif (116 KB | )
anescapewfreq.gif
 
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john racic
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Re: micro amp captures
Reply #7 - Jun 10th, 2010 at 5:56pm
 
On the Ford Escape captures they are NOT zoomed the same.  The idle capture is zoomed at 8x, and the higher speed one is zoomed at 64x.

For some reason the capture shows a square wave on the idle capture, and a more rounded one as the speed increases.

The Honda capture was zoomed the same.

The Escape has a cracked tone ring.  That's what caused the "signature" in the waveform.  We will try to get a picture and post it for those who have not seen this.

John and Mike
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john racic
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Re: micro amp captures
Reply #8 - Jun 10th, 2010 at 6:06pm
 
Earl Davis wrote on Jun 10th, 2010 at 5:40pm:
Do you have some other uses for this probe?
What size wire will the probe fit around?


Earl

Sorry, was on autopilot, and didn't realize you had posted a question.

Yes, we have tried a few other things with this probe.  MAF and we are still trying to get neat AFR captures.  This is obviously the way things are going, microamp analysis will certainly become more and more useful.  Those posts will be here soon!  Anyone with other suggestions, we are certainly interested, please pass them on!

The probe looks like a normal amp clamp that went through the "honey i shrunk the kids" machine.  Handy to get into tight places.  I would guess it would fit around a #12 wire.  Since it only has a capacity of 450 milliamps, that is big enough.

The electronics are located in a box, like the way the Fluke PV350 is, with the same kind of B plug connector, on the end of a few foot cable, so it does not get in the way.

John and Mike
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Mick
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Re: micro amp captures
Reply #9 - Jun 10th, 2010 at 7:14pm
 
Hi John and Mike

The voltage waves can be rescaled to show the square waves like I have seen before.

Nissan versions of these sensors will not give you that on the voltage line, so I would love to see a nissan abs sensor please.

It did a great job on the cracked tone wheel.

Thanks for putting the probe to the test

Mick
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Re: micro amp captures
Reply #10 - Jun 10th, 2010 at 7:48pm
 
Mick wrote on Jun 10th, 2010 at 7:14pm:
The voltage waves can be rescaled to show the square waves like I have seen before.


mick, i was gonna ask about that.  the voltage trace isn't as nice as the amp trace, but i think there is some value in it.  especially if you add some vert zoom.  but you say nissans don't do this?
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Mick
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Re: micro amp captures
Reply #11 - Jun 10th, 2010 at 8:09pm
 
crackerclicker wrote on Jun 10th, 2010 at 7:48pm:
Mick wrote on Jun 10th, 2010 at 7:14pm:
The voltage waves can be rescaled to show the square waves like I have seen before.


mick, i was gonna ask about that.  the voltage trace isn't as nice as the amp trace, but i think there is some value in it.  especially if you add some vert zoom.  but you say nissans don't do this?


That is correct. I think I have some captures of nissans somewhere but flat lines are boring to post. Wink


Mick
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Re: micro amp captures
Reply #12 - Jun 10th, 2010 at 11:14pm
 
Very cool! I can't wait to get one.
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Re: micro amp captures
Reply #13 - Jun 10th, 2010 at 11:21pm
 

Thank you John and Mike.   Cool

I could be mistaken, but I think this is another Autonerdz first.  I don't think anything like this has ever been seen before.   Shocked

Would this be advanced Buttonology®?   Grin
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Mike Lappert
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Re: micro amp captures
Reply #14 - Jun 12th, 2010 at 12:30pm
 
Here's a picture of the tone ring.
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tone_ring_2.jpg (37 KB | )
tone_ring_2.jpg
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