Programmable logic controller: Difference between revisions

Revision as of 11:02, 31 July 2002

Revision as of 00:23, 26 August 2002

Line 1:

A programmable logic controller or PLC is an electronic appliance designed to replace a bulky cabinet full of relay logic. The input is usually a set of contacts with flow or absence of electrical current. The outputs simulate switches.

ItA consistsPLC ofis a small computer running a program. The program reads the inputs of the logic controller, calculates a custom logic function, and then produces the outputs.

Unlike general purpose [[computer]]s, PLCs are designed to be used by electricians who train on the job. They are usually programmed in a language called "[[ladder logic]]", which strongly resembles a blueprint of relay logic. PLCs are also available that can be programmed in more traditional programming languages.