8
3 Specifications of 16131.5
3.1 Specifications of 16131.5
16131.5 measures the solar radiation received by a plane surface from a 180° field of view angle. This
quantity, expressed in W/m
2
, is called “hemispherical” solar radiation.
The instrument is classified according to ISO 9060 and should be used in accordance with the
recommended practices of ISO, IEC, WMO and ASTM.
Table 3.1.1
Specifications of 16131.5
16131.5 MEASUREMENT SPECIFICATIONS:
ISO classification (ISO 9060:1990)
First class pyranometer
WMO performance level (WMO-No. 8,
seventh edition 2008)
good quality pyranometer
Response time (95 %)
< 10 s
Zero offset a (response to 200 W/m
2
net
thermal radiation)
5 W/m² unventilated
Zero offset b (response to 5 K/h change in
ambient temperature)
< 4 W/m
2
Non-stability
< 1 % change per year
Non-linearity
< 1 % (100 to 1000 W/m
2
)
Directional response
< 20 W/m
2
Spectral selectivity
< 3 % (0.35 to 1.5 x 10
-6
m)
Temperature response
< 2 % (-30 to +50 °C)
Tilt response
< 2 % (0 to 90 ° at 1000 W/m
2
)
Measurement range
0 to 3000 W/m
2
Zero offset steady state
< 1 W/m
2
(-40 to + 80 °C)
Spectral range
(20 % transmission points)
285 to 3000 x 10
-9
m
Figure 3.1.1
Spectral response of the pyranometer compared to the solar spectrum. The
pyranometer only cuts off a negligible part of the total solar spectrum.
Measurand
hemispherical solar radiation
Measurand in SI radiometry units
irradiance in W/m
2
Optional measurand
sunshine duration
Field of view angle
180 °
Output definition
running average over 4 measurements, refreshed every 0.1 s
Recommended data request interval
1 s, storing 60 s averages
Temperature range of application
-40 to + 80 °C
IEC 61724-1:2017 COMPLIANCE
IEC 61724-1:2017 compliance
meets Class B PV monitoring system requirements
