RayTek MI Miniature Infrared Sensor - Manual (Page 35)

Installation
MI 27
• Ambient background temperature compensation from a second
temperature sensor (infrared or contact temperature sensor)
ensures extremely accurate results. For example, the output of
the second unit, set for mV output, could be connected to the
FTC2 analog input (0 to 5 VDC corresponding to low end and
high end of temperature range) is utilized for real time
compensation, whereby both sensors must be set on the same
temperature range.
Figure 16: Principle of Ambient Background Temperature
Compensation
Sensor 2
targeted
to ambient
Sensor 1
targeted
to object
Thermal radiation
of ambient
Thermal radiation
of target
0 – 5 VDC
analog output
at FTC2 input
Furnace wall
Target object