The Robertshaw Model 5100 Level-Lance is a microprocessor based, advanced technology On-Off level detection instrument. By utilizing the microprocessor, the device can be calibrated without screwdriver adjustments or knobs to turn. The simplicity of the “Auto Set” calibration is the ultimate in level control ease of adjustment. The Model 5100 has eight (8) separate and individual programs pre-programmed into its memory. These programs let the user select the “type” of On-Off control action best suited for the application. The eight programs are field selectable by means of a 10 position rotary switch.