Endurance
®
Series
Users Manual, Rev. 2.0, Jun 2020
38
5.6.2.2 Background Temperature Compensation
The sensor can improve the accuracy of target temperature measurements by considering 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.
Background temperature compensation allows for the impact of reflected radiation in accordance with 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 collected by the sensor. The ambient background temperature
compensation adjusts the result by subtracting the amount of ambient radiation measured from the sum of thermal
radiation the sensor is exposed to.
Note
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 sensing head temperature
is utilized for compensation if the background temperature is
more or less represented by the internal sensing head temperature. This is the default setting.
•
If the background temperature is known and constant, the user may give the known background
temperature as a
constant temperature value
.
•
Background temperature compensation from a
second temperature sensor
(infrared or contact
temperature sensor) ensures extremely accurate results. For example, a second infrared sensor,
configured to provide a 0 to 20 mA output scaled for the same temperature range as the first sensor can
be connected to the analog input to provide real-time background temperature compensation.
Figure 5-10: Principle of Background Temperature Compensation
Use ASCII commands to configure the analog input, see section 14.5.3
Background Temperature Compensation
page 122.
Sensor 2
targeted
to background
Sensor 1
targeted
to object
Thermal radiation of background
Thermal radiation of target
0
– 20 mA
analog output
at analog input
Furnace wall
Target object
