What are control systems?

A control system makes decisions about how a discrete, continuous, or hybrid processes function, generally ensuring processes operate within appropriate parameters, safely, at an appropriate rate, and within required quality. Control systems help factories and facilities produce quality goods safely and efficiently. Open-loop control is when the output (decision) doesn’t feed back into the control loop. Closed-loop control uses the output to influence, or provide feedback for, the next decision. Control systems can include hardware and software for programmable logic controllers (PLCs), programmable automation controllers (PACs), embedded systems and edge computing, dedicated controls, proportional-integral-derivative (PID) and advanced process controls (APC), along with distributed control systems (DCS), supervisory controls and data acquisition (SCADA), and other controllers, such as industrial PCs (iPCs).
Courtesy: Honeywell Process Solutions
DCS, SCADA, Controllers April 3, 2020

Know when to migrate a process control system

There’s a big difference between a phased process control system migration and just putting delaying the problem of control system obsolescence. Those who don’t plan for distributed control system (DCS) obsolescence will see options narrow.

By Satnam Bhogal
PID, APC July 3, 2018

Ladder logic’s future role in automation

Nine considerations when selecting a programming language. Ladder logic is favored by manufacturers in discrete industries, but as technology and automation evolve, its usefulness compared to other IEC 61131-3 programming languages and PC programming depends on application complexity and other factors.

By Jon Breen, Breen Machine Automation Services
Sensors, Actuators March 4, 2018

Process control sensor types and applications

Taking accurate, reliable measurements of process parameters that matter is the first step to optimizing any control loop. You cannot improve what you do not measure. Process sensors help, including temperature sensors, pressure sensors, level sensors and flow sensors (flow meters).

By Mark T. Hoske, Control Engineering
Figure 1: Offline proportional-integral-derivative (PID) simulator. Courtesy: Sasol
PID, APC March 6, 2017

The PID learning process

While there are many excellent loop tuning methods available, many practitioners prefer tweaking proportional-integral-derivative (PID) tuning constants or using rules-of-thumb rather than doing the required step test and data analysis. But having knowledge about how the individual PID components interact can go a long way to learning proper tuning theory and methods.

By Nic van der Mey, Gustaf Gous
Figure 1: DC motors work well in low cost, low speed or constant-torque applications such as on this belt-driven roller conveyor. Courtesy: AutomationDirect
Business of Engineering February 8, 2017

How to select a motor for an industrial application

Cover Story: Understanding the main types of loads, motors, and applications can help simplify industrial motor and accessory selection.

By Bryan Sisler