No. The LI-250A does not require recalibration, but the sensor attached to it does. We recommend recalibrating light sensors every two years.

One of two reasons: Either the calibration constant is entered with the incorrect sign (it should be entered with a negative sign (-)) or the polarity of the connector is switched. With the LI-192SA and LI-193SA, the cable might be connected incorrectly to the sensor. Be sure that the yellow dot and nub are aligned where the cable connects to the sensor. See this video for more guidance.

In some instances, the internal storage is not retained when the batteries are removed or when the batteries become discharged. Check the multipliers stored in the instrument and verify that they are correct for each sensor. Re-enter them if necessary.