MembersPage/BorisRieken/TempSensors

I have three temp sensors. CLT, IAT and EGT. And I want to calibrate them. I allready ordered a digital thermometer. So I can calibrate CLT and IAT.


EGT calibraion

Look at http://www.vems.co.uk/VEMS/egt.html Step 5.

Cold is easy: short the EGT inputs (eg. alligator clips) and verify offset is reasonable (reading appr. the same as the temp of EGT input, within a few degrees). Let's say it's 20C and you read 15C (it won't be precise enough for human body temp measurement, but perfect for EGT).

Knowing the K-thermocouple slope: 40uV/C, that is +40mV between EGT inputs => +1000C (that is 1015C reading if the v3 temperature is 15C), you can finetune the egt_cal (0x49 .. 0x4a are most common IIRC). You can apply 15..50 mV with a voltage divider. The exact value does not count, just measure with your DVM so you can divide it by 40uV/C to get the delta-temp in C.


And I have an open IAT sensor. Can i put this one in hot water also?

This is a picture of the open IAT sensor:

iat.jpg

With an NTC type IAT, take a v3 readings

We can help you finetune the curve than. Better than playing with hot liquids. If you really insist hot liquids, boil water and put the sensor into waste cooking oil on top of it (to avoid changing resistance with the conductivity of water). WhatEverYouDoYouDoItAtYourOwnRisk


Did some tests with clt sensor in water with digital thermometer and dvm. But I'm confused. This is what I measured:

30 degrees Celsius = 1713 Ohm

40 degrees Celsius = 1205 Ohm

50 degrees Celsius = 857 Ohm

60 degrees Celsius = 640 Ohm

100 degrees Celsius = 189 Ohm

When I calculate my sensors nominal resistance (at +25C) the way it is explained on the EasyTherm/SensorTable page. Everytime I get a really different outcome. At 100 degrees 2700 is the best choice. And at 40 degrees 2252 is the best choice. Is there something I'm doing wrong here?

I allready think that I know what it is. The clt sensor is slow. Because today i did the same measurements with my iat sensor. And it is at 2700 all the time.


Ran tempsensor_upload.bat 2700 2063 256. clt and iat readings are fine now in free air.