infrared temperature sensor

[RavensFan]

You need to look up the specifications for your sensor.  It must have some sort of datasheet.  It must show some sort of voltage to temperature conversion.  Whether it is a linear conversion, non-linear, or perhaps some sort of lookup table, the datasheet will give you the details.

[badrmoh]

Thank you very much for your reply.

it is a relationship between voltage and emissivity

U in V  = 0.0 - 0.5 - ......... - 4.5 - 5.0

Emissivity = 0.1 - 0.2 ........- 1.0 - 1.1

These are the relation in the datasheet, but I do not know how can I convert emissivity to temperature.

[RavensFan]

Create 2 1-D arrays of the data.

Use the function called Threshold 1-D array to search for the index of the voltage in the voltage array.  Then use that index with Interpolate 1-D array to look up the corresponding emissivity.