Using Discrete-Event Computer Simulation To Test Control Systems

The material handling control system of an automated manufacturing facility is tested during the commissioning of the plant. This leads to protracted commissioning periods as well as the possibility of costly equipment damage. The testing is performed in a modular fashion so that complex interaction are often overlooked. It is suggested that simulation can play a valuable part in speeding up the commissioning stage of plant startup by interfacing the control system to a computer simulation of the factory. The control system receives information about the state of the manufacturing system from the simulation and the simulation receives information from the controller on what to do next. By developing a complete simulation model and running the simulation for long periods of simulated time, the control system can be tested rigorously prior to the plant startup. The emphasis of this paper is on some of the important practical concerns of linking a discrete-event simulation system to a controller. The impact this has on the simulation model will be discussed in conjunction with two small example problems. The examples will include some of the code used to connect the controller and the simulation.