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I recently made the mistake of purchasing a combo temp and pressure sensor that I was going to use to replace my adapter on adapter setup with individual sensors that I currently have.
The issue with this specific sensor is that for a temp range of -40-500(f) the resistance change was 84-197. If you know anything about temp. sensors you will realize this is way too low and provides a very poor resolution; 0.4v with 1kΩ pull-up or 0.9v with 100Ω pull-up. With this small of a voltage range, and 540(f) of total temp range, any sort of noise is bound to give us errors. With 100Ω pull-up we run the risk of running enough current to heat the sensor a bit and cause false readings.
My Link FuryX only allows calibration tables with Volts, however Holley EFI systems do allow resistance to be input on certain temp. inputs (Haltech as well I believe). My understanding is that the Holley EFI would still be reading the voltage though, and just has a resistance table as an ease-of-use.
This low resistance sensor has reportedly been used successfully with the Holley EFI, and was made for use with it. Does the Holley have some different internals that allow it to accurately read this sensor? Is it actually as bad as I think it is?
Either way I won't be using it, and make sure to double check the calibration tables make sense before ordering your sensors.
Some data acquisition systems (like AIM logger), have the ability to "scale" the input. So they can handle a 0-50mV, 0-0.5V or 0-5V signals all with the same 12-bit resolution. The system determines how to do this based on the voltage range of the sensor calibration.
I found this out doing strain gage calibrations with only a few tenths of a volt, and the data would flat-line above the 500mV level.
I would suspect the Holley has something similar.
Thanks David for the input. I still would hate to have such a small voltage range. I think noise could definitely cause some issue