Kipp&Zonen BSRN Scientific Solar Monitoring System - Manual (Page 102)

90
Pyrheliometer Specification List
Specification Class of Pyrheliom eter
Secondary
Standard
First Class Second Class
Response tim e: tim e for 95% response < 15 s < 20 s < 30 s
Zero off-set:
response to 5 K h change in am bient
-1
tem perature
± 2 W m ± 4 W m ± 8 W m -2 -2 -2
Resolution (sm allest detectable change in W m ) ± 0.5 W m ± 1 W m ± 5 W m -2 -2 -2 -2
Stability (percentage of full scale, change/year) ± 0.5 % ± 1 % ± 2 %
Non-linearity:
percentage deviation from the responsivity
at 500 W m due to change in irradiance within
-2
100 W m to 1000 W m -2 -2
± 0.2 % ± 0.5 % ± 2 %
Spectral selectivity:
percentage deviation of the product of the
spectral absorptance and the spectral
transm ittance from the corresponding m ean
within 0.3 :m and 3.0 :m
± 0.5 % ± 1 % ± 5 %
Tem perature response:
total percentage deviation due to change in
am bient tem perature within in interval of 50 K
± 1 % ± 2 % ± 10 %
Tilt response:
percentage deviation form the responsivity at 0°
tilt (horizontal) due to change in tilt from 0° to
90°at 1000 W m irradiance
-2
± 0.2 % ± 0.5 % ± 2 %
Traceability: m aintained by periodic com parison with a prim ary
standard
pyrheliom eter
with a
secondary
standard
pyrheliom eter
with a first
class
pyrheliom eter
or better
Table B 1.2. Pyrheliom eter specification table from ISO 9060.