Search results
Results from the WOW.Com Content Network
PLCs have many variations. In Shirley M. Hord's 1997 definition, it means "extending classroom practice into the community; bringing community personnel into the school to enhance the curriculum and learning tasks for students; or engaging students, teachers, and administrators simultaneously in learning".
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis.
As practiced in K-12 education in the United States, practice-based professional learning develops and integrates a school's use of curriculum and assessment, instructional leadership, and professional learning communities (PLCs) to create a system-wide shift in day-to-day classroom instruction. [8]
Note: In this example, "Run" represents the status of a bit in the PLC, while "Motor" represents the actual output to the real-world relay that closes the motor's real-world circuit. For safety reasons, an emergency stop ("ES") may be hardwired in series with the "Start" switch, and the relay logic should reflect this.
Process controls (basic as well as advanced) are implemented within the process control system, which may mean a distributed control system (DCS), programmable logic controller (PLC), and/or a supervisory control computer. DCSs and PLCs are typically industrially hardened and fault-tolerant.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Early examples of FPGAs are the 82S100 array, and 82S105 sequencer, by Signetics, introduced in the late 1970s. The 82S100 was an array of AND terms. The 82S105 also had flip-flop functions. (Remark: 82S100 and similar ICs from Signetics have PLA structure, AND-plane + OR-plane.)
Standard IEC 61131 is divided into several parts: [3]. Part 1: General information. It is the introductory chapter; it contains definitions of terms that are used in the subsequent parts of the standard and outlines the main functional properties and characteristics of PLCs.