Sensors with resistance outputs

PopKorn78 · Post by **PopKorn78** » Mon Mar 23, 2015 1:08 am

Here are the data I have

One is from the data with engine not running
two is with the engine running
and the last one is the calibration I made.

Of course the car puts up more voltage when it runs, but it seems to only affect the RCP and not the physical gauges. The RCP is wired directly to the battery so that it does not shut down when I turn off the power to the car.

Post by **brentp** » Mon Mar 23, 2015 1:30 am

Since you're running 12v gauges your reference voltage changes when the car is on (~13.6-14.4v) vs off (11-12v)

You'll want to re-measure everything while engine is running so you get the correct calibration voltage.

In contrast - when you're using a dedicated sensor, you would use a constant reference voltage that is the 5v output from RaceCapture/Pro. This 5v is constant regardless of engine running state.

You can see a wiring diagram of a dedicated sensor connected to the 5v reference here:
http://autosportlabs.net/RaceCapturePro ... ure_Sensor

Hope this helps.

toga94m · Post by **toga94m** » Mon Mar 23, 2015 2:14 am

You say you're wired to the battery, but battery voltage displays 4.5V? Sounds like you're running from a USB adapter instead of +12V right to the RCP?

PopKorn78 · Post by **PopKorn78** » Mon Mar 23, 2015 10:54 am

Yep, when I took the screen shot I was on USB