PLC controlled elevator drive system

This paper presents a control method for an advanced electrical drive system for transportation, namely an elevator. For cost efficiency the control is performed with the simplest appropriate PLC. Thus, the software code was wisely developed to be fast and small size. Starting from an educational platform, which models a two floor elevator using a DC electrical drive, different sensors types and a PLC, the development of the actual driving sequences and PLC program, written using ladder diagram language, is detailed. In order to account for various normal operation and malfunctioning scenarios, some testing techniques are presented as well as their implemented into the PLC's program. Thereby, the paper has also an instructive aspect for engineers working in the automation field.

I. Introduction-PLCs

Programmable Logic Controllers (PLCs) appeared in the US around 1969. They were originally intended to automate assembly lines [1]. It is considered like a particular type of computer, having the task to command industrial machines or other automated applications such as: keep a water level, control a reactor or a traffic light system [2]–[5], manage a manufacturing cell transport system [6]–[8], or command elevators (this is the example that it is developed).