7
the heater only during night-time. Combining a heater with external ventilation makes these heating
offsets very low.
Version 00.16131.501040 offers irradiance in W/m
2
as a 4-20 mA output. It must be used in
combination with suitable power supply and a data acquisition system which is capable of handling a
4-20 mA current loop signal.
Version 00.16131.501000 offers irradiance in W/m
2
as an analogue millivolt output. It is a passive
sensor and does not need a power supply. It can be connected directly to commonly used data
logging systems. In order to reduce the effect of dew deposition and frost on the outer dome surface,
00.16131.501000 has a built-in heater. The heater is coupled to the sensor body. Heating a pyrometer
can generate additional irradiance offset signals, therefore it is recommended to activate the heater
only during night-time. Combining a heater with external ventilation makes these heating offsets very
low.
The irradiance in W/m
2
is calculated by dividing the 00.16131.501000 output, a small voltage, by the
sensitivity. This sensitivity is e.g. provided on its calibration certificate.
The central equation governing 00.16131.501000 is:
E = U/S
U: Voltage output in V
S: Sensitivity in V/(W/m
2
)
E: Solar irradiance in W/m
2
