optris CTratio Operator's Manual page 43

This figure is showing the typical temperature reading of a ratio thermometer optris CT ratio in both the 1-
color- and the 2-color-mode in addiction of increasing contamination of the optical transmission path in-
between the target and the ratio thermometer. Due to the ratio principle the 2 channel signal (upper curve)
stays very stable over a wide range of attenuation up to over 90%. The signal of the 1 channel mode (lower
curve), acting like in a standard pyrometer with one measuring wavelength only, is decreasing rapidly with
the contamination of the transmission path.
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