Delta Electronics SS1-UM-1.05 - Manual (Page 72)

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Technical Reference section Document code: SS1-UM-1.05
PAR Performance
The graphs below show the actual spectral and cosine response curves for the
SunScan system.
Spectral response
The spectral response curve shows that the SunScan response is almost entirely
within the PAR wavelength band of 400 nm - 700 nm. The GaAsP sensors used have
an increased sensitivity towards the red end of the spectrum, but this is compensated
for by the sharp cut-off at 670 nm. In practice, we have found that these sensors read
to within a few percent of an accurate PAR sensor in natural daylight conditions
above or within the canopy. However, if you are working under artificial or strongly
coloured light you should check the SunScan readings against an accurate PAR
sensor if you need to know absolute PAR levels.
Spectral response
0
20
40
60
80
100
120
140
160
350 400 450 500 550 600 650 700 750
w avelength nm
re
lative r
esponse %
SunScan
Ideal