Press the PRESET button once to simultaneously set sensitivity and reset the display value to 100. The preset function is more prominent when using multiple sensors, making it easy and fast to find dirty or offset sensors. The current value is set to " ". The FS-N10 series offers a variety of models with different features, including output types, power modes, and detection modes. • Once the preset function is disabled, the setting value is recalculated while retaining the ratio of the setting value and received light. This is the SET push button; this is used to calibrate the sensitivity.