Elevator control system modeling and PLC program generating based on SIPN

Abstract

This paper researches into the modeling method of elevator control system and the algorithm of generating PLC program based on Signal Interpreted Petri Net (SIPN). We also analyze the properties of the SIPN model in the system. SIPN is obtained by adding input and output signals into the ordinary Petri Net. Input signals are related to every transition in SIPN, which express the firing conditions of the transition, while output signals related to the corresponding place, which express the control information of the place. In the SIPN model of the system, the relationships are established from one to one correspondence between the Input and Output (I/O) signals of SIPN and the I/O points of PLC. The places of the SIPN stand for the statuses of the elevator, and the transitions represent the changes of the statuses. The input signals of system are the actions of pressing buttons and some sensor signals, which represent the conditions of changing the states of elevator. The output signals are the actions of elevator control functions, such as stop, open, and close the door, which describe the output control information of the elevator in every place. A case study demonstrates the validity both of the SIPN model and the algorithm.