Control's 10 most-read articles from February 2018

March 19, 2018
From choosing the right valves and controllers to the top companies in the industry, these were the most-read articles on during February 2018.

1. Controllers: Direct vs. Reverse-Acting Control
Valve failure position and controller actions are independently determined. In this article, Béla Lipták and other experts tackle both issues. Read more. 

2.Linear or equal percentage valves: When should I use which?
Béla Lipták and other experts take on the question of when to use equal percentage or linear control valves. The selection goal should be control loop stability. Read more. 

3. Positioned for recovery: Top 50 automation companies of 2015
Aautomation supplier revenues missed a curve in fiscal 2015, as both global and North American revenues are down significantly from 2014. The picture isn’t all bleak for process automation, however. Even in 2015, some oil and gas sectors performed well. Read more. 

4. Patience has rewards: Top 50 automation companies of 2016
The process control and automation businesses of the Top 50 global and North American suppliers still face some challenging headwinds, and 2016 was a tough year. Traditional automation suppliers are betting on big transformations into the world of the Internet of Things (IoT) to rejuvenate their businesses. Read more. 

5. 2018 Readers' Choice Awards
Today’s industrial facilities increasingly rely on vendors to not only deliver high-performance, rugged, durable equipment and expert services at rock-bottom prices, but to back those products and services with competent, immediate, 24/7 support. Only the strongest suppliers can generate the loyalty that leads to a place in our Readers’ Choice Awards. Read more. 

6. Live from Rockwell Automation Fair 2017
The editors of Control, Control Design, and Smart Industry are on site at provide breaking news and best sessions while on site at the Rockwell Automation Fair 2017. Read more. 

7. Beginner's guide to differential pressure level transmitters
One method to avoid a "garbage in, garbage out" (GIGO) scenario is to understand the measurement technique and its limitations to the extent that its application can be reasonably evaluated. Differential pressure level measurement is one of those key measurements you need to understand to avoid the dreaded GIGO. Read more.

8. Capacity control of reciprocating compressors
Today, with increasing capacities and power ratings of new reciprocating compressors, advanced methods can help to eliminate use of recycle valves, save energy, improve controllability and save costs. This article explains the basic theories of traditional and advanced capacity control methods for reciprocating compressors. Read more.

9. The art of flowmeter selection
Greg McMillan and Stan Weiner speak with Hunter Vegas, co-founder of the ISA Mentor Program, about the good, the bad and the ugly of today's most common technologies. Read more.

10. First cyber attack on unguarded SIS reported
One of the first—if not the first—documented cyber attacks on a safety instrumented system (SIS) was reported on Dec. 14 by the FireEye and Dragos  blogs. Read more.