Mixing instrumentation protocols

Is it possible to use both HART and fieldbus devices in the same environment?

01/26/2012


Dear Control Engineering: Looking at the article about the HART Plant of the Year, it sounds like that Shell facility uses both HART and Foundation fieldbus. How much can you mix those technologies?

You’re probably referring to this statement: “All the functionalities, beginning with pre-commissioning to normal operation, were the same for HART and Foundation fieldbus devices. Shell uses both and has taken full advantage of both technologies; the biggest benefit being that we did not have to subject our HART devices to any separate interoperability testing.”

The simple answer is that you can’t mix the two on the device level, but you certainly can have both technologies in the same plant. I suspect there are few, if any plants with more than a handful of tags that have 100% of their devices on fieldbus networks.

FF devices only work on fieldbus segments with fieldbus I/O. FF is an all-digital protocol, and between the two, it can carry more information.

HART is a hybrid using a 4-20 mA analog signal to carry the main PV with a digital overlay that carries additional variables, diagnostics, and configuration information. It is possible to use HART devices as purely analog without ever accessing the digital overlay. The two protocols can only talk to their respective I/O, and the device transmitters are different.

The interoperability testing the author refers to is likely something of a pre-configuration process which normally has to be done to both kinds of devices, at least to some extent.

Here are some additional articles that can fill in the more of the blanks: 

HART Communication proves valuable on a major project, contributes to a successful startup

Using HART with asset management systems

Performing device integration testing for Foundation fieldbus devices

Device diagnostics and asset management

www.hartcomm.org

www.fieldbus.org

Peter Welander, pwelander@cfemedia.com



The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Robotic integration and cloud connections; SCADA and cybersecurity; Motor efficiency standards; Open- and closed-loop control; Augmented reality
Controller programming; Safety networks; Enclosure design; Power quality; Safety integrity levels; Increasing process efficiency
Additive manufacturing benefits; HMI and sensor tips; System integrator advice; Innovations from the industry
Featured articles highlight technologies that enable the Industrial Internet of Things, IIoT-related products and strategies to get data more easily to the user.
This article collection contains several articles on how automation and controls are helping human-machine interface (HMI) hardware and software advance.
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Cloud, mobility, and remote operations; SCADA and contextual mobility; Custom UPS empowering a secure pipeline
Infrastructure for natural gas expansion; Artificial lift methods; Disruptive technology and fugitive gas emissions
Mobility as the means to offshore innovation; Preventing another Deepwater Horizon; ROVs as subsea robots; SCADA and the radio spectrum
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Jose S. Vasquez, Jr.
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me