Machine Safety

Machine Safety October 1, 1998

4-20 mA Transmitters Alive and Kicking

Because they've been around so long, everyone already knows all there is to know about 4-20 mA transmitters and how to install them. But, if so much is known about selecting and installing 4-20 mA transmitters, why do the same questions keep coming up? Questions like:Transmitter classificationsUnderstanding differences between two-, three- and four-wire devices will help clear up several ...

Machine Safety September 1, 1998

Tons of Technologies Hit Houston

They may or may not beat the Texas heat, but visitors and exhibitors at ISA Expo/98 will certainly find what they need to clobber competitors at this year's event.Billed by organizers as the biggest control and instrumentation show ever, ISA Expo/98 is the second alternate-year-format event for ISA, the international society for instrumentation and control (Research Triangle Park, N.

By Jim Montague, Control Engineering
Machine Safety September 1, 1998

Designing and Applying Remote Field Instruments

A remote field instrument is a device used to sense a physical parameter such as pressure or temperature. This measurement is translated to a signal current in the range of 4-20 mA which is proportional to the measured variable. The 4-20 mA standard has provided an excellent platform for the development of process instrumentation.

By Albert O' Grady and Jim Ryan, Analog Devices B.V.
Machine Safety September 1, 1998

Can We Talk?

It seemed like a simple enough question. "How many pages we will have in the September issue?" I asked our managing editor. "That depends on who's counting," he replied. Our business department monitors pages according to ad revenue; the post office counts pages by demographic distribution; and we editors count pages in terms of articles, news, and other information in the magazine.

By Jane S. Gerold
Machine Safety September 1, 1998

Pressure Calibration Onsite or In the Lab?

Keeping processes running to specification requires accurate calibration of plant instrumentation. Pressure instrumentation, including gages, switches, transmitters, transducers, and differential-pressure units, all require this attention on a regular basis. Calibration equipment types vary widely.

By Robert N. Cash, Fluke Corp.
Machine Safety September 1, 1998

PLC architecture can provide high safety integrity

There's no safety like nuclear safety. Consequently, process safety instrumented systems (SIS) requiring a high safety integrity level (SIL) can benefit from a programmable logic controller (PLC) architecture used in nuclear safety systems. (See this issue's cover articles for related safety topics.

By Staff
Machine Safety September 1, 1998

Improving Safety in Process Control

Environmental law, customers, and good business sense require finding effective ways to integrate plant safety into industrial process systems. No one wants an unsafe situation, but overengineering safety can put a company out of business almost as fast as a major violation.Regulatory agencies' standards and regulations require process plants to protect against accidental damage to person...

By Charles M. Fialkowski, Moore Process Automation Solutions
Machine Safety August 1, 1998

Sensors get smart

Adding intelligence to sensors is a definite trend in the industry. Not too long ago, users were content with just on/off contacts. Engineers now are eager to implement networks. With machine uptime a critical issue, the ability to implement diagnostics to improve maintenance response is also essential.

By Staff
Machine Safety July 1, 1998

Enclosures—Think Outside the Box

Considering the globalization trend of industry, a completed control system may be shipped anywhere in the world. To discover what users want and need in enclosures, Control Engineering surveyed 1,500 readers. Of the 465 responses, 50% work in process industries while 39% identified their primary application as discrete product manufacturing.

By Staff
Machine Safety July 1, 1998

Copper’s Not the Only Way to Network

You have to install a new manufacturing data network. Before you call for a truck-load of twisted-pair copper wire, better check out all the applications. There may be areas where copper won't work.There are other choices. Fiber-optic technology is not new, but is becoming easier to use. Radio frequency is moving from warehouse data collection to sensors and networking.

By Gary A. Mintchell, Control Engineering