The response of the LI200R, LI200RX, LI200X, LI200S, LI190R, or LI190SB sensor to solar radiation is calibrated at LI-COR. Following that procedure, the LI200RX-L, LI200X-L, and LI200X-LC (for MetData1s) are returned to Campbell Scientific to have the internal potentiometer "tweaked" to output the proper mV signal levels. If LI-COR repairs the housing, cable, or photodiode, additional repair charges will apply. All factory calibrations require an RMA (Return Material Authorization).