Programming and Simulation of Control Algorithms using Computer Graphics

Abstract

A system for the programming and evaluation of process control algorithms has been developed. A graphical block diagram language was adopted to provide an easy means of programming via a graphic terminal. A number of pre-defined blocks are provided and programming is achieved by connecting the required blocks together. The graphic blocks correspond to software modules performing the required control functions. The pictorial program is then compiled to give a machine-independent program structure table. This can then be linked with the block routine code to provide the target processor's control program to realise a required control algorithm. A similar graphic approach was adopted for simulation of the controlled processes, so that the performance of the control algorithm may be evaluated. The use of standardised software modules and computer graphics simplifies programming and the maintenance of system documentation. The interaction and communication between the two subsystems (control scheme and process model) supports the testing and evaluation of control algorithm. The data structures for effective graphics and efficient execution of the blocks are specified. The various functions necessary for the compilation of the graphical program are investigated and analysed.