# Calculation Of Temperature

Calculation Of The Object Temperature Derived From 4 Sampling Points Using Linear Interpolation

Selection of 4 sampling points (sensor voltages) V1 ,V2 ,V3 and V4

can be done according to following

**principle :**

Measurement of the thermopile voltage and temperature reference signal. Determination of the actual

sensor temperature derived from the measured temperature reference signal.

The calculated sensor

temperature is used to find the bordering ambient temperature rows in the data array. Now the sampling points for the interpolation can be defined, if one of the array data isn’t the value looked for accidentally.

The values of the selected rows are searched for the largest value less than the measured thermopile

voltage. The search starts at the lowest object temperature row in the two selected ambient temperature rows.

The following equation helps to find the right points e.g. by a software program. The right sampling points have been selected, if the condition “ VY> F” is complied. „F“ stands for the measured thermopile voltage.

V1 ,V2 ,V3 ,V4 -> Sampling points from the data array

F -> Thermopile voltage

CTO -> Step range of the object temperature axis (temperature difference between 2 rows)

CTA -> Step range of the ambient temperature axis

TA -> Difference between sensor temperature and axis temperature related to the sampling points

TO -> Difference between calculated object temperature and axis temperature related to the sampling points.

The object temperature can be calculated by linear interpolation using following equation

Updated almost 3 years ago