Campbell Scientific LI190SB LI-COR Quantum Sensor - Manual (Page 15)

LI190SB Quantum Sensor
6. Maintenance and Calibration
DO NOT use alcohol, organic solvents, abrasives, or strong detergents to clean
the diffuser element.
The acrylic materials used in LI-COR light sensors can be crazed by exposure
to alcohol or organic solvents, which will adversely affect the cosine response
of the sensor.
Clean the sensor only with water and/or a mild detergent such as dishwashing
soap. Vinegar can also be used to remove hard water deposits from the
diffuser element, if necessary.
Keep the sensors clean and treat them as a scientific instrument in order to
maintain the accuracy of the calibration. The vertical edge of the diffuser must
be kept clean in order to maintain appropriate cosine correction.
The LI190SB should re recalibrated every two years. Obtain an RMA number
before returning the sensor to Campbell Scientific, Inc. for recalibration.
7. Troubleshooting
Symptom: -9999 or radiation values around 0
1. Check that the sensor is wired to the Differential channel specified by the
measurement instruction.
2. Verify that the Range code is correct for the datalogger type.
3. Disconnect the sensor leads from the datalogger and use a DVM to check
the voltage between the red (+) and the black (-) wires. The voltage
should be 0 – 10 mV for 0 to 1000 Wm
-2 radiation. No voltage indicates a
problem with the photodiode, cable, or the variable shunt resistor.
Symptom: Incorrect solar radiation
1. Make sure the top surface of the sensor head is clean, and that the sensor
is properly leveled.
2. Verify that the Range code, multiplier and offset parameters are correct
for the desired engineering units and datalogger type.
8. Acknowledgements
Campbell Scientific, Inc. gratefully acknowledges the contribution of LI-COR
to concepts, text, and images used in this manual.
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