A Virtual Programmable Logic Controller

Applications

Industrial applications for the PLC include the manufacturing, food, petro-chemical and construction industries. PLCs have been widely used in the food industry, for example, to control processes such as freeze drying and cake making.

A typical application - furnace control

The control of an industrial furnace used to be achieved using electro-mechanical temperature/process contollers and relays to provide sequencing of valve operations, conveyor drives, and the mechanical movement of plant. All of this can now be controlled by a PLC, which allows for more accurate process control, and monitoring of parameters such as temperature, pressure and flow. Instrumentation and management is improved by using the the PLC to communicate with other systems. The PLC drives MIMIC diagrams, displays process parameters, and provides a number of other features that allow direct control of plant and the logging of information. An integrated control and instrumentation system like this is usually referred to as a Supervisory Control and Data Aquisition (SCADA) system.