Development of a four-story elevator system for teaching motion control concept with programmable logic controller

The motion control and the programmable logic controller (PLC) are essential sub-modules in the industry automation systems. The integration of motion control teaching components into a course has been successful for the past two years. Practicing programming with a PLC trainer provides a limited range of real world experiences which usually involves various motion control components. Therefore, various assignments using input/output (I/O) devices could be given to students to exercise development of ladder logic diagrams. But more dynamic applications with motion control components are necessary to train and prepare students for the real world. The development of the PLC controlled four-story elevator is the final project assignment for students in the advanced PLC course. This final project requires the following tasks: the development of interfacing software for the human machine interface (HMI) terminal, the design of a hoist using a stepper motor, the implementation of a position-sensing mechanism, the completion of a ladder logic diagram for entire elevator control and the development of a miniature four-story frame that will enclose a carriage. In this paper, various PLC-based motion control topics, which are necessary to complete the final project, are introduced and the implementation details of the PLC controlled four-story elevator is discussed.