A Matlab/Simulink Framework for PLC Controlled Processes

Relevant literature recognises that the practical test of an automation and control process controlled by programmable logic controllers (PLC) is a well-known problem [1-3]. There are several solutions that can be implemented, such as scale models, batteries of led’s and switches and Human Machine Interfaces (HMI), Supervisory Control and Data Acquisition (SCADA) systems, or simulation tools. The use of scale models of real processes is very expensive and difficult to adapt to different processes. There is no question that this is the best way to teach PLC controlled process, allowing project testing in an almost real environment, however their cost often prohibits its use. The use of leds and switches sets is extremely confusing end uninteresting. This approach, only valid when small processes are considered, severely reduces the motivation. Some HMI and SCADA systems allow this feature but there are very expensive, not intended for this purpose and usually consider property protocols. The use of Matlab®/Simulink® [4] has not been a regular approach for teaching industrial automation and PLC controlled processes. Assuming that the model of the industrial process is implemented in the Matlab/Simulink, this chapter presents a tool that can be used to implement the PLC control program in Matlab/Simulink environment. The basic idea is to consider the PLC control program as a Matlab function block, within the Matlab/Simulink environment, that will control the model of the industrial process as long as the simulation runs. The main objective of the work described in this chapter is to automatically translate the PLC control program, written as an instruction list, into Matlab/Simulink software language. 11