PCs have become more useful as part of open architecture control systems.
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.
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...
Many professions involve some certification procedure whereby practitioners can demonstrate competency. For lawyers, it's the bar exam. For accountants, it's the CPA. For engineers, it's the P.E.—the Professional Engineer's license.A P.E. license entitles practitioners to advertise themselves as "engineers" and offer engineering services to the public.
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.
The National Electrical Code (NEC) defines a ground as ‘a conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth, or to some conducting body that serves in place of the earth.’ A ground loop can be defined as any objectionable current flowing in a circuit’s ground or return path. Here is a short guide that will help identify possible sources of ground loops in your electrical systems and how to solve them. The simplest ground loop involves connection between two different earth grounds as shown in the top figure. With earth ground #1 at one potential, and earth ground #2 at a different potential, a ground loop current will flow in the loop as indicated.
Explosions can be prevented by limiting the amount of electrical energy available in hazardous areas or by containing the situation using bulky, heavy devices called ‘explosion-proof enclosures.’ Limiting excess electrical parameters such as voltage and amperage (current) requires the use of energy-limiting devices known as ‘intrinsically safe (IS) barriers.’ Explosion-proof enclosures prevent or control explosive situations with brute force. They are heavy containers designed to hold an explosion inside. Electrical devices within explosion-proof enclosures can operate at normal power levels.
BUS OF THE MONTH: AS-i Bus
Bus of the month
BUS OF THE MONTH: Profibus-DP