"The illuminance sensor is a kind of the RS485 bus-type illuminance sensor,using RS485 interface and standard MODBUS-RTU protocol which enable the sensor’s function of multi-point monitoring,networking and teletransmission. The sensor is applicable for various places, especially for agricultural greenhouses urban lighting and other places. The following are various environmental illuminance values:lux Night without moon:0.001—0.02; Night with moon:0.02—0.3; Cloudy day indoors:5—50; Cloudy day outdoors:50—500; Sunny day indoor:100—1000;The illumination at noon under the sun: about 10^6; Illumination required for reading books:50—60; The standard illumination of household video camera:1400."