Design and impelimentation of dc motor speed control using PLC

Abstract

Direct current (DC) motor has already become an important drive configuration for many applications across a wide range of powers and speeds. In industries, it is very much required to maintain speed of DC motor accurately or precisely for some applications like drills, lathes, spinning and weaving, elevators, cranes etc. This thesis is concerned on design and implementation of DC motor speed control using Programmable Logic Controller (PLC). It is a closed-loop real time control system, where proximity sensor is placed near to the motor shaft to provide the feedback speed signal to controller. PLC and DC Drive makes major role in maintaining the speed of DC motor. PLC gets feedback signals form motor by means of proximity sensor which sends pulse signals, to PLC and PLC accept pulse signals from proximity sensor which will monitor the gating pulses to check the speed, where function blocks are available in PLC to convert these gating pulses to speed of motor. Then PLC will direct to dc drive to correct the speed by changing armature voltage by means of PWM techniques to maintain the motor at constant speed. The PWM is used to control duty cycle of DC motor drive. Through thesis, it can be concluded that PLC can control motor speed at desired speed although there is a variation of load