Computer aided design of relay ladder diagram from functional specifications

Abstract

The author describes two complementary software programs, called PROLOC and AILISTD, which make up a high-level computer-aided design package that transforms functional specifications into relay ladder design for direct implementation in a programmable logic controller (PLC). AILISTD uses artificial-intelligence techniques to transform the functional specifications into a state transition diagram (STD) representation. PROLOC then translates the STD specifications into relay ladder design for programming into a PLC. A laboratory example involving a liquid level control system illustrates the use of both programs.<>