Aug
31
Over the last 10 years I have worked with a number of technologists from the process industry on various aspects of control using wireless field devices. Much of this work is summarized in the book Wireless Control Foundation – Continuous and Discrete Control for the Process Industry. Recently Mark Nixon (Emerson) and Willy Wojsznis (Emerson), …
Jul
27
Willy Wojsznis, Mark Nixon and I co-author the paper Model Predictive Control With Event Driven Operation for the “1st European Experts’ Workshop On Emerging Trends In Event Based Systems” . In this paper we address how wireless measurements have been successfully used in the application of MPC in the control of a Divided Wall Column …
Feb
16
In late November, 2014 I traveled to Dubai to teach the Control Loop Foundation class. This class is based on the book Control Loop Foundation – Batch and Continuous Processes and is a standard class offered by Emerson’s education department. In this class the students used the book’s web site to perform the workshops that …
May
19
In a blog posted late last month I addressed how to provide a 24VDC source of power to a three wire field device. In the past I have used a 24VDC High Side Discrete output to provide 24VDC to these types of devices. This solution can be implemented in most DCS and PLC systems. If …
Apr
28
Some field devices such as an inductive proximity switch may be designed as three wire devices that require a 24VDC source of power. In such cases it is possible to tap into the 24 volt bulk power supply in the rack room and run twisted pair to the device. However, to protect against a short …
Apr
21
During the TC65 Plenary meeting each working group gives an activity report that summarizes the status of standards that are being developed or updated. At the Hamburg meeting, March 31- April 4th I was a delegate to the SC65B and SC65C meeting and lead the US delegation in the SC65E meeting. The reports by Peer …
Apr
14
The international standards for industrial-process measurement, control and automation are developed through IEC TC65. As stated on the IEC web site, the standards developed by TC65 address systems and elements used for industrial-process measurement and control concerning continuous and batch processes. These standards address equipment and systems operating with electrical, pneumatic, hydraulic, mechanical or other …
Apr
07
Many of the international standards that we depend on in the process industry were created by working groups within IEC TC65: Industrial-process measurement, control and automation. IEC TC65 holds a plenary meeting every two years to review the status of work to develop or update international standards. The most recent plenary meeting was held March …
Jan
27
In many tank level control applications, a level switch is installed and used as an interlock to help prevent overfilling the tank. For example, in many existing installations you may find a vibrating fork liquid level switch wired as an input to the control system. However, today it is possible to reduce the cost of installing a …
Jan
20
Many manufacturers initially introduced WirelessHART field devices that were designed to support continuous process measurements such pressure, flow, temperature, and level. Also, WirelessHART transmitters are now available for analytical measurements such as pH. Recently you may have noticed that some manufacturers have introduced WirelessHART field devices for discrete measurement. For example, Rosemount has released the …
