Type 11. 91 Light Dependent Relay “twilight switch” for the automatic control of lighting according to the ambient light level – using a separate photosensor. Auxiliary output, for use with 19. 91 Power Module, provides an output directly related to the light level (i. e. without intervention of any time delays). Features include: “Daily” time switch function – programmable to inhibit main output (for energy saving), Auxiliary output – directly driven by the photosensor, Italian patent “Light feedback compensation” principle, Sensitivity adjustment from 1 to 150 lux, LCD display for status indication, set-up and programming, Internal battery for set-up/programming without supply and for time/program back-up in case of power failure (5 years), Low stand-by power consumption, SELV separation between contact and supply circuit, Double insulation between supply and photosensor, 35 mm rail (EN 60715) mount, Cadmium-free contact material, Cadmium-free photosensor (IC photo diode)