Mastering Internet of Things

Modeling a Programmable Logic Controller

A Programmable Logic Controller, or PLC, is a device with some generic functionality that can be configured (or programmed) in certain ways to interact with its surroundings. Typically, it contains a series of input or output modules, either analog, digital, and/or serial. More advanced PLCs contain other types of objects as well. If the PLC is to be connected to the network, it makes no sense to create an individual connection for each input/output module. Instead, the PLC gets a single connection.

Some PLCs can be modeled as a single sensor or actuator with a sequence of input fields (for example, Input 1, Input 2, ...) or output fields (Output 1, Output 2, and so on). But it would make more sense ...