SENSORS CALIBRATION
Calibration of analogue sensors is done from the Sensors Setup level.
Coolant temperature sensor (CLT) and intake air temperature (IAT) sensors
IAT and CLT sensors are in most cases the NTC thermistors. NTC thermistor is a nonlinear
resistor, whose resistance depends strongly on temperature of the resistance material. As its
names indicates (Negative Temperature Coefficient) thermistor has a negative temperature
coefficient, so its resistance decreases when temperature grows.
These sensors are connected to the EMU device in the following way:
IAT and CLT sensor calibration takes place by using 2D tables, respectively, IAT Calibration and
CLT Calibration. This table defines the divider’s voltage created by the sensor and built in the EMU
pull-up resistor corresponding to the given temperature. In order to facilitate the sensor calibration,
you should use the wizard.
Using the wizard we can use the
predefined sensor, or create its
characteristic, providing the sensor
resistance for 3 known temperatures. The
highest difference of temperatures is
recommended in the wizard (these data
can be found in the car’s service book or
can be collected with ohmmeter in 3
different temperatures)
Page 39
EMU
B4
B21
CLT
IAT
CLT and IAT sensors wiring diagram
B18
B18
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