Software Dyno...

[CSH-HQ]

>> From:          "Rich Vandervoort" <richvandervoort at hotmail.com>
>
>> Here's how we used to get wheels speeds from competitors ABS systems.  Tap 
>> into the wheel speed signal at the ABS controller.  Note use twisted pair 
>> wiring with a grounded shield, do not route near spark plug wires or similar 
>> noise sources.  The consequence of noise on wheel speeds can be no brakes. 

OK, How???.  No way would a possible failed speed sensor disable the entire 
braking system, maybe no abs, but that could happen anyway
Bruce

>
>UUH...OK that cans that idea for me. in fact heres an official "don't 
>try this at home" stamp.  THUMP ;-) 
> 
>> Just use an off the shelf F to V converter (frequency to voltage) and feed 
>> the resulting analog signal into something that can use to record the signal 
>> versus time.  Calibrate a voltage to speed conversion using steady speed and 
>> some reliable speed measurement device(speedo?).  Note use an undriven wheel 
>> and the signal will be extremely accurate as there are usually something 
>> like 50 teeth on a speed ring.  Note your wheel speed tap may put noise on 
>> the speed signal if you do not match the polarity of the F to V and the ABS 
>> controller.  Also the newer ABS systems have quite sophisticated wheel speed 
>> diagnostic circuits and may disable ABS once the F to V is hooked up.  We 
>> used to buffer the signal, but I am unsure of the circuitry.
>> 
>> 
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>> 
>~~~
>Dave Z. www.delanet.com/~tgp
>