Kipp&Zonen BSRN Scientific Solar Monitoring System - Manual (Page 118)

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B 4. Pyrgeometers
B 4.1 Eppley Precision Infrared Radiom eter (PIR)
This pyrgeom eter is a developm ent of the Eppley Precision Spectral Pyranom eter. It is intended for
unidirectional operation in the m easurem ent, separately, of incom ing or outgoing terrestrial radiation as
distinct from net long-wave flux. This instrum ent com prises the sam e type of wirewound-plated therm opile
detector and cast bronze desiccated case as the PSP. Tem perature com pensation of detector response
is likewise incorporated. Radiation em itted by the detector in its corresponding orientation is autom atically
com pensated, elim inating that portion of the signal. A battery voltage, precisely controlled by a therm istor
which senses detector tem perature continuously, is introduced into the principle electrical circuit.
Another innovation is aim ed at isolating infrared radiation from solar short-wave radiation in daytim e. This
is accom plished by replacing the glass hem ispherical system of the pyranom eter with a silicon hem isphere.
On the inner surface, there is a vacuum -deposited interference filter. T he transm ission range of the
pyrgeom eter window is approxim ately 3.5-50 :m .
A calibration certificate and a wiring diagram are included.
Specifications
Sensitivity: approx. 4 :V W m -1 2
Im pedance: approx. 700 S.
Tem perature Dependence: ±1 % over am bient tem p. range -20 to +40 °C.
Linearity: ±1 % from 0 to 700 W m -2
Response tim e: 2 seconds (1/e signal).
Cosine: better than 5% from norm alization, insignificant for a diffuse
source.
Mechanical Vibration: tested up to 20 g's without dam age.
Calibration: blackbody reference.
Size: 5.75 inch diam eter, 3.5 inches high.
W eight: 7 pounds
Orientation: Perform ance is not affected by orientation or tilt.
Tem perature Measurem ent Therm istor YSI 44031
Specification for ventilator
Input Power: 110 - 120 V, 60 Hz (or other specified supply).
Output: approx. 30 CFM.
Size: 8 inch diam eter, 5.75 inches high.
W eight: 5.5 pounds.
B 4.2 Eko MS-201 Precision Pyrgeom eter
For m easurem ent of long wave radiation, beyond 3 :m .