THE use of function blocks for programming of programmable logic controllers (PLCs) is gaining wider acceptance. Rather than the classic “contact and coil” representation of ladder diagram or relay ...

This simple logic probe has both LEDs on with no signal at the input but due to the nor gates connected to the probe, indicates correctly when a high or low signal is present. It also works correctly ...

This tutorial offers an in-depth introduction into programmable logic controllers (PLCs). The article starts with an overview of the history and the role PLCs in factory automation. The basic ...

For many years, factories have used PLCs for automated control over industrial equipment. These systems are usually expensive, proprietary, and generally incapable of being reprogrammed. [Oliver], an ...