DCS, SCADA, Controllers
More users, system integrators, and manufacturers of control hardware and software are realizing the benefits of digital networks at the sensor, device, and fieldbus levels.In this kickoff of the "Year of the Network" series, Control Engineering asked leaders associated with 12 major industrial networks to reveal growth projections, ideal applications, views on standards, and future out...
Marlborough, Mass.— Dataflo-C is a digital proportional, integral, derivative single-loop controller. The device, which is aimed at industrial processes, features a rugged valve and actuator package, on-board diagnostics, autotuning capability, and remote or local setpoint control. It accepts a variety of process inputs and can take total control of process parameters either locally or v...
PID loops control a majority of the automated processes in industrial facilities. The proportional-integral-derivative (PID) algorithm is both simple and reliable, and has been applied to hundreds of thousands of control loops over the last 50 years.However, not all industrial processes can be controlled with PID loops.
Several developments are underway as Cutler-Hammer/Eaton migrates from PLC-based controls to Open Automation (OA), DCS- and PC-based systems, and soft-logic software. So C-H's new $2 million, state-of-the-art training center here is just the tip of the iceberg comprising its recent expansion effort.
The southern tip of California's Marin county is separated from the city of San Francisco by the most famous mile-long strip of steel and concrete in the world. Yet, within a 10-minute walk of the Golden Gate's Marin terminus begins a county-wide network of California Wildlife Service signs warning against mountain lion attacks.
BUS OF THE MONTH:ARCNet
Tuning a PID controller is conceptually simple–observe the behavior of the controlled process and fine tune the controller’s proportional (P), integral (I), and derivative (D) parameters until the closed-loop system performs as desired. However, PID tuning is often more of an art than a science. The best choice of tuning parameters depends upon a variety of factors including the dynamic behavior of the controlled process, the controller’s objectives, and the operator’s understanding of the tuning procedures. Self-tuning PID controllers simplify matters by executing the necessary tuning procedures automatically.
BUS OF THE MONTH: LonWorks
A feedback controller is designed to generate an output that causes some corrective effort to be applied to a process so as to drive a measurable process variable towards a desired value known as the setpoint. Shown is a typical feedback control loop with blocks representing the dynamic elements of the system and arrows representing the flow of information, generally in the form of electrical signals. Virtually all feedback controllers determine their output by observing the error between the setpoint and the actual process variable measurement. PID control A proportional-integral-derivative or ‘PID’ controller looks at the current value of the error, the integral of the error over a recent time interval, and the current derivative of the error signal to determine not only how much of a correction to apply, but for how long.
Controllers that juggle multiple process variables are neither simple nor common, but they can handle some of the most complex control problems.