Design and implementation of a statechart based reconfigurable elevator controller

This paper presents a simple and clear method to design and implement a reconfigurable elevator controller using an FPGA, which can be implemented for an elevator with any (N) number of floors, with specified inputs and outputs. A model based design approach was followed. We started from a state chart model developed for a prototype elevator with three floors. Extension of the model for a variable number of floors was considered. Controller for the prototype system was implemented in ladder logic on a PLC and the limitations of that approach with regard to re-configurability were identified: viz., in the extension of elevator controller for `N' no of floors. Next VHDL code was developed for a reconfigurable elevator controller where, by changing a variable corresponding to the required number of floors, the suitable code can be generated. The controller thus generated can be implemented in an FPGA. The method was successfully tested on a Xilinx Spartan 3AN FPGA.