- Thu Nov 05, 2020 9:08 pm
#46238
Hi,
my temp readings are way off and I did measure my sensors. I chose sensors to match in TunerStudio and wrote the bias resistor value to 2490 ohm as per the manual. But the readings are way off. Now I measured these (darn small SMD) resistors, R1 and R3, and the AIT one (R1) measures 6530 ohm, and the CLT one (R3) 7290 ohm. Now my eyes are too bad to see let alone read the markings on the SMD resistors, but this is weird. It is common for these resistors to be so far out of spec? If there is someting influencing the measurement is could only be parallel to the resistor hence lowering the measurement, so something increasing the measurement from 2490 to the measured values seems unlogical to me.
Needless to say, both the 2490 values and the measured values don't give me an accurate reading. I just changed the bias resistor values to 24900 (ten times the manual value) and now I at least have a decent reading for ambient temperature on both sensors. This is weird, is there a 10x factor somewhere I missed?
Is there something else going on?
Cheers,
Hugo
my temp readings are way off and I did measure my sensors. I chose sensors to match in TunerStudio and wrote the bias resistor value to 2490 ohm as per the manual. But the readings are way off. Now I measured these (darn small SMD) resistors, R1 and R3, and the AIT one (R1) measures 6530 ohm, and the CLT one (R3) 7290 ohm. Now my eyes are too bad to see let alone read the markings on the SMD resistors, but this is weird. It is common for these resistors to be so far out of spec? If there is someting influencing the measurement is could only be parallel to the resistor hence lowering the measurement, so something increasing the measurement from 2490 to the measured values seems unlogical to me.
Needless to say, both the 2490 values and the measured values don't give me an accurate reading. I just changed the bias resistor values to 24900 (ten times the manual value) and now I at least have a decent reading for ambient temperature on both sensors. This is weird, is there a 10x factor somewhere I missed?
Is there something else going on?
Cheers,
Hugo
Last edited by HugoW on Sun Nov 15, 2020 7:32 am, edited 1 time in total.