Datasheet
Application Information
AMBIENT TEMPERATURE COMPENSATION
A2TPMI
Ô
Because of many physical effects, that influence the non-contact temperature measurement based on
infrared radiation, it is difficult to meet the best initial adjustment for a specific application. Therefore
some deviations might be found at first measuring. For all applications the optimized solution can be
prepared and fixed based on the measurement in the application environment. PerkinElmer is pleased
in providing you assistance to find the conditions, which deliver the highest accuracy in your application.
The temperature compensation is only working well within a certain ambient temperature range, limited
by different device parameters of the thermopile sensor and the temperature reference sensor. The
following diagram shows a typical characteristics and is only an example for better understanding of the
principle compensation curve. The curve shows the deviation for a correct working of a compensated
module.
Temperature Deviation of VTobj vs. Ambient Temperature
3
Typical Temperature Deviation [K]
2,5
2
1,5
1
0,5
0
-20
-0,5
0
20
40
60
80
100
Ambient Temperature [°C]
The compensation of the module sample in the diagram is adjusted to the best fitting at 20°C to 80°C
ambient temperature, but the curve can be shifted in the whole ambient temperature range through the
change of A2TPMI parameters.
MEASUREMENT TOLERANCE
The temperature error of the A2TPMI depends on several factors like the emissivity, object temperature,
object size to spot size relation, temperature gradients over the sensor housing in the environment,
device tolerances and the optimal adjustment of the ambient temperature compensation.
The accuracy as specified under V
Tamb
and V
Tobj
characteristics is based on theoretical calculation as
well as on statistical evaluation results. The PerkinElmer quality system ensures that all A2TPMIs are
calibrated and tested under a certain test conditions in order to guarantee these specifications.
However, due to the nature of infrared remote temperature measurements there might occur limits ex-
ceeding or deviations in specific application environments. In this case please contact the PerkinElmer
application support to help you solving the problem.
A2TPMI Datasheet Rev4
Page 11 of 21
Rev. Oct 2003
PERKINELMER [ PERKINELMER OPTOELECTRONICS ]
