RayTek MI Miniature Infrared Sensor - Manual (Page 34)

Installation
26 MI
5.4.3 Ambient Background Temperature Compensation
The sensor is capable of improving the accuracy of target
temperature measurements by taking into account the ambient or
background temperature. This feature is useful when the target
emissivity is below 1.0 and the background temperature is
significantly hotter than the target temperature. For instance, the
higher temperature of a furnace wall could lead to hotter
temperatures being measured especially for low emissivity targets.
Ambient background temperature compensation compensates for the
impact of the reflected radiation in accordance to the reflective
behavior of the target. Due to the surface structure of the target, some
amount of ambient radiation will be reflected and therefore added to
the thermal radiation that is collected by the sensor. The ambient
background temperature compensation compensates the final result
by subtracting the amount of ambient radiation measured from the
sum of thermal radiation the sensor is exposed to.
The ambient background temperature compensation
should always be activated in case of low emissivity
targets measured in hot environments or when heat
sources are near the target!
Three possibilities for ambient background temperature
compensation are available:
• The internal sensor head temperature is utilized for
compensation assuming that the ambient background
temperature is more or less represented by the internal sensor
head temperature. This is the default setting.
• If the background ambient temperature is known and constant,
the user may give the known ambient temperature as a constant
temperature value.