Campbell Scientific NR01 Net Radiometer - Manual (Page 25)

NR01 Four-Component Net Radiation Sensor
For the CR3000 and CR5000 dataloggers, one differential channel and a
current excitation channel are used to measure the PT-100.
For the other dataloggers, two differential channels and the 4WPB100 module
are required to measure the Pt-100 temperature sensor.
FIGURE 5-1. 4WPB100 Module
If free channels are limited it is possible to measure the PT100
sensor using a 3WHB10K terminal input module, with only a
slight loss of accuracy. This only requires one differential
channel. Please refer to the documentation for that module for
further details. NOTE
5.1 Calibration Factors
Each NR01 is provided with a ‘Certificate of Calibration’ by the manufacturer.
This certificate shows the sensor serial number and ‘sensitivity’ of each of the
four component sensors. Unlike some other models of sensor, the individual
components are not modified in an attempt to have a common calibration.
Therefore, individual calibration factors must be applied in the datalogger
program to convert the voltages to energy fluxes in W m
-2
The calibration factor is in units of uV/(W m -2 ), which needs to be converted to
units of (W m -2 )/mV for the multiplier parameter in the datalogger program.
To convert the units, divide the calibration factor into 1000. For example, if
the calibration factor is 7.30 uV/(W m
-2 ), the multiplier is 1000/7.3 = 136.99
(W m -2 )/mV.
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