A integrated virtual learning system is being researched and developed to teach students
about programmable logic controllers (PLCs). This system, called the Virtual PLC,
incorporates intelligent tutoring system, simulation, and animation technologies. This article
describes the development and evaluation of modules on PLC timer and counter
instructions. These modules were first developed using an intelligent tutoring system (ITS)
authoring tool and animation tools. After the concept was proved positively, a Web‐based …

Programmable logic controllers (PLC) are used for many industrial process control
applications, such as monitoring security, managing energy consumption, and controlling
machines and automated production lines. The total PLC and software market was $7.2
billion in 2006 with steady growth expected over the next five years. Thus there is a
continuing need for engineers with strong skills and knowledge in this area.