Design and implementation of a programmable logic controller based day lighting control system

Automatic lighting in building automation is a technology mainly designed for energy efficiency and uniformity of illumination during working hours. In this paper design and implementation of automatic lighting controller, consists of low cost and simple approach of electric lighting interface module with Programmable Logic Controller (PLC) is presented. The electric lamps were controlled inside the building in order to achieve illumination according to bureau of National Building Code of India (NBCI). To achieve illumination standard, the number of lamps were accordingly determined and their illumination levels were maintained automatically with the use of PLC. In order to quantify the results obtained by the PLC as a controller, the results were also obtained for without the use of controller. It is observed that, illumination levels were found to be 300–310 lux and 120–160 lux for with and without controllers respectively. Further, uniformity ratio and power consumption were also estimated. It is observed that, the uniformity ratios were found to be 0.9–0.95 and 0.1–0.15 for with and without controller respectively. Thus, illumination level of luminaries and uniformity ratio with controllers are in close agreement with the values of NBCI. Also the power consumptions of the lamps used in the system with and without controllers were found to be 100 W and 400 W respectively. Therefore, it may be inferred that the proposed model is said to be efficient in saving power. That is the power saving of nearly 75% is said to be achieved in a system of lighting control using PLC.