Instructions

HD2402 - 14 - V1.3
Different limits correspond to different spectral intervals. Some spectral bands coin-
cide with the spectral response of the utilized sensors, while other sensors need to
properly combine several channels. The table shows how HD2402 channels are com-
bined to obtain 13 of the requested 15 limits. Limits e, f are beyond the measure-
ments achievable with the instrument and, on the other hand, are applied to particu-
lar sources (typically, ophthalmology instruments).
Limit Nominal spectral
range
Effective spectral
range
Channels
a 180nm÷400nm 220nm÷400nm f (ch2, ch5)
b 315nm÷400nm 315nm÷400nm ch5
c, d 300nm÷700nm 315nm÷700nm f (ch5, ch6, ch7)
g, h, i 380nm÷1400nm 380nm÷1400nm f (ch3, ch6, ch7)
j, k, l 780nm÷1400nm 700nm÷1400nm ch3
m, n 780nm÷3000nm 400nm÷3000nm ch9
o 400nm÷3000nm 400nm÷3000nm ch9
Table 5: calculation of a-o limits from channels available in the instrument
The quantity measured by HD2402 instrument is always irradiance (or illuminance for
what concerns channel 0), while limits c to l are calculated from the radiance value.
As illustrated in chapter 2 (Radiometry overview), the two quantities are related and
radiance can be obtained from irradiance (assuming that radiance is constant), pro-
vided that the geometric parameters of the measured source are known.
The details of the calculation will be shown in the software description. Even in case
the geometric parameters of the source are not known, it is anyway possible to esti-
mate the requested quantities.