Sensor readings are negative (-) or zero:

Sensor readings are incorrect:

  • Make sure the meter or logger is properly configured, including entering the sensor's correct calibration multiplier. Note that multipliers are different from the calibration constant, and there are different multipliers for use with millivolt adapters (see Calibration Constants and Multipliers).
  • Check the sensor's last calibration. Certificates of calibration are available at: Enter the sensor's serial number in the calibration data search box. Certificates include multipliers and the sensor's last calibration date. LI-COR recommends factory recalibration for radiation sensors every two years (Factory Recalibration).
  • Check for loose cable connections. Moisture on connections can also cause erroneous readings.
  • Check the sensor cable for damage, including nicks, cuts, or sharp bends.
  • Contact LI-COR technical support ( if you are unable to resolve the issue.