One-Step: automating logic translations and creating CAD drawings for process controls

Abstract

The loop logics used in an electronic control system for process controls are usually implemented through CAD drawings or loop schematics. To execute loop logic algorithms, the CAD drawings are first translated into logic equations. The logic equations are then compiled into executable binary files that are finally loaded into the controller memory. The process of translating CAD drawings into logic equations is laborious and errors prone, especially for a system with a great number of inputs and outputs. It is therefore desired to automate the translation process, and achieve error-free implementation and conversion of loop control algorithms, especially for critical loop controls as applied in the nuclear industry, where safety and reliability are always the primary concern. For this reason, One-Step software has been developed. One-Step software not only automates the logic translations but also creates dynamic images of a CAD drawing for display on the workstations so that logic drawings can be dynamically monitored with the system on-line. Since the CAD drawings are created and stored in one source electronically, human errors in archiving a great volume of logic schematic drawings are also eliminated. Hence, human errors in the logic translations and the archiving of logic schematic drawings can be eliminated and real-time on-line monitoring of system dynamic status is achieved. These, coupled with a proven and reliable control system, secure the success of critical process controls in industry applications. In this paper, a plant control system is first introduced. Then, the necessity of developing One-Step software for translating CAD drawings into text equations is demonstrated through an example process control loop. Next, One-Step design architecture is illustrated. Finally, One-Step implementation-its creating processes of logic equations and CAD images are described in details. The paper ends with concluding remarks.