scaling for dummies

[jakekooser]

I'm trying to get my AFR readout to match the LED display provided by Zeitronix with my ZT-3.
Their scale is here:

I have configured my RCP like in the config.php file attached.

When I start the car, the RCP display on the computer shows 15.32 while the LED shows 14.7

How can I correct the discrepancy, assuming the LED is correct, as it is hard-wired to the controller?

Thanks,

Jake

[rocket6706]

attached is a typical scaling for a Wideband O2 Sensor. Since the output is linear you could use a simple ratio to bias the line of the Display to the Line of the RCP based on known values (i.e, known display of A/F ratio and measured voltage). If 2:14.2 = X:14.7 solve for X and plug it into the RCP. Once you have three points you have a straight line.

[brentp]

when in doubt, use a meter to directly measure the voltage right at the terminal block of RCP - then the mapping should turn it into real-world value.

You can bypass the sensor and just use a 3 legged potentiometer to create a voltage divider between vRef and ground - as the voltage sweeps between 0-5v your scaled value should change accordingly as well.

Looks like you're on the right track overall!