THE CONTROL VALVE HANDBOOK
The fourth edition of the Control Valve Handbook presents vital information on control valve performance and the latest technologies. The book is both a textbook and a reference on the strongest link in the control loop—the control valve and its accessories. It includes knowledge from experts in the process control field, including contributions from ISA and Crane Co. Read it here.
Emerson Process Management
CONTROL VALVE ACTUATORS
Control valves need actuators to operate. This tutorial briefly discusses the differences between electric and pneumatic actuators, the relationship between direct acting and reverse acting terminology, and how this affects a valve’s controlling influence. The importance of positioners is discussed with regard to what they do and why they’re required for many applications. Read it here.
AS-I NETWORKS FOR ACTUATORS
In 1990, a consortium of successful companies in Germany created a bus
system for networking sensors and actuators called Actuator Sensor Interface (AS-Interface or just AS-i). This bus was meant to meet some requirements based on the experiences of the group’s founding members, and supply the market’s
bit-oriented hierarchy. So, the AS-i network was conceived to complement other systems, and to simplify and speed up connections between sensors, actuators and their controllers. This online tutorial explains how to set up such a network. Read it here.
A GATHERING OF EAGLES
Get 200 years of valve experience right here. Béla Lipták, Greg Shinskey, Harold Wade and Greg McMillan sort out the knotty question: why two valves don’t open and close at the same rate? Why does the heating valve close too soon compared to the cooling valve? Read this special edition of Ask the Experts here.
DIAGNOSING SMART POSITIONER PROBLEMS
This free, 18-page PDF explains use of electronic device description language to diagnose failures in smart instruments, including valves, actuators and positioners. It also covers instruments using Foundation fieldbus, HART, WirelessHART and Profibus. Read it here.
VALVE POSITIONER TUTORIAL
The Industrial Automation and Mechatronics Portal (IAM) offers a variety of tutorials on valves and other automation subjects. It also contains links to blogs, reference texts, whitepapers, industry news and other information. Check out the tutorial on valve positioners, which is part of a larger “Final Control Elements” section.
ALL ABOUT ACTUATORS
This link takes you to a complete selection of actuator subjects, including subsea and offshore valve actuators, high-pressure manifold actuators, safety-related systems, spring-return hydraulic and pneumatic actuators, compact, double block-and-bleed (DBB) valve actuators and more. There are a total of 21 actuator subjects in all, as well as electrical actuator design and operation, All the articles are free. Read it here.
ASSUME THE POSITION
The paper, “Positioners—Pneumatic, Electro-Pneumatic, I to P Conversion,” covers the basics of positioning pneumatically activated valves. It describes 10 different systems for valve positioning, from simple on-off actuated valves to modulating a valve using a diaphram or piston actuator, and on up to the complexities of using a diaphram or piston actuator fitted with a digital valve controller using HART, Profibus or Foundation fieldbus links. The free PDF requires no registration. Read it here. The direct link is at http://bit.ly/1rY6UD4.