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Old 12-19-2011, 12:32 PM   #20
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Joined: Apr 2003
Location: Long Beach, CA
Oddometer: 11,887
Originally Posted by Andrew View Post

Can those signals be acquired through simple analog or digital DAQ?
I could put a 16-bit DAQ card in my laptop, and sample eight channels at 125 kHZ each.
They can, you'll need to connect directly to the signal sources. The data Roger is collecting is passed as serial data to the GS-911, from the ECU diagnostic port.

There's a lot of different signals. Below is a list of the minimums specs to get usable fuel and spark timing data:
TPS: Two 0-5V signals, 10bit/100Hz
O2 Sensor: One 0-1V signal, 10bit/50Hz
Hall Effect: Two 0-12V signals, 1bit/1MHz
Fuel Injector: One 0-12V signal, 1bit/10MHz
Ignition Coil Driver: One 0-12V signal, 1bit/1MHz

For example, 125KHz isn't fast enough to capture the sub-microsecond resolution of the fuel injector signal pulse. The ECU adjusts the injector pulsewidth with sub-microsecond resolution.


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