Campbell Scientific NR-LITE2 Net Radiometer - Manual (Page 20)

NR-LITE2 Net Radiometer
TABLE 7-2. Datalogger Connections for Single-Ended Measurement
Function
Color
CR10X,
CR510,
CR500
CR23X,
21X, CR7 CR800,
CR850,
CR1000,
CR3000,
CR5000,
CR9000(X)
Radiation Signal Red S.E. Channel S.E. Channel S.E. Channel
Signal Reference Blue AG
Shield Black G
7.2 Datalogger Programming
This section is for users who write their own datalogger
programs. A datalogger program to measure this sensor can be
generated using Campbell Scientific’s Short Cut Program
Builder Software. You only need to read the calibration portion
of this section if using Short Cut. NOTE
The NR-LITE2 outputs a low-level voltage ranging from 0 to a maximum of
about 15 mV. A differential voltage measurement (VoltDiff() in CRBasic or
instruction Volt (Diff) (P2) in Edlog) is recommended because it has better
noise rejection than a single-ended measurement. If a differential channel is
not available, a single-ended measurement (VoltSE() in CRBasic or instruction
Volt (SE) (P1) in Edlog) can be used. The acceptability of a single-ended
measurement can be determined by simply comparing the results of single-
ended and differential measurements made under the same conditions.
7.2.1 Input Range and Integration
Normally the 15 mV range for the 21X or CR7, the 25 mV range for the
CR800, CR850, CR1000, CR10(X), or CR500/CR510, and the 50 mV range
for the CR3000, CR5000, CR9000X, or CR23X are suitable.
The slow or 60 Hz rejection integration gives a more noise-free reading. A fast
integration takes less power and allows for faster throughput.
7.2.2 Calibration Factor
Each NR-LITE2 is provided with a Certificate of Calibration by the
manufacturer which shows the sensor serial number and a sensitivity or
calibration factor. This calibration factor, after conversion, is used in the
datalogger program. Always cross check to ensure that the serial number of
your NR-LITE2 and the number on the calibration certificate are identical.
The serial number and sensitivity are also shown on a small label attached to
the connecting arm near the head of the sensor itself.
The calibration factor included on the Certificate of Calibration is in units of
µV/(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
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