Kipp&Zonen BSRN Scientific Solar Monitoring System User Manual
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Figure 8.1. Percentage change in infrared flux due to case therm istor errors.
Using these values, the difference between the m easured tem perature at a given resistance
and the calculation at that resistance is no m ore than 0.02 °C through the tem perature range
-60 °C to 50 °C. Figure 8.1 illustrates the effect of a positive deviation in the determ ination
of the case tem perature on the calculated ‘case flux’ from the correct value. This difference
m ay be due to sam pling errors, an incorrect therm istor reading (e.g. the case therm istor is
not representing the actual cold junction tem perature) or an incorrect therm istor inversion
equation. As can be seen, unless the error is greater than approxim ately 5%, the overall accuracy
of the m easurem ent is not greatly affected.