Fieldbus & Industrial Networking


Augmenting process automation solutions

April 2010 Fieldbus & Industrial Networking

Replacing analogue 4-20 mA technology with a digital network was a major driver behind the development of Foundation Fieldbus technology. However, what really differentiates Foundation Fieldbus from Profibus PA, HART, and other process automation technologies, is the incorporation of a function block structure and other supporting functions that make Foundation technology a complete infrastructure for process automation.

By allowing control functionality to be embedded in the field devices themselves, Foundation Fieldbus enables a degree of availability that approaches that of single-loop controllers. By distributing the control functions out to field-mounted actuators or measurement devices, there is no single point of failure in the system above the H1 level. Thus, even if a failure should occur in the HMI or plant network, the field-based control loops can continue to function. A backup link active scheduler (BLAS) can also be used to enable a field control loop to continue functioning even if there is a failure in the primary LAS. What is more, in cases where control normally resides in the DCS, field-level control can add another level of redundancy. Many end users have already managed to avoid unplanned downtime when field-level control took over after a failure in the DCS.

Evidence suggests that control in the field provides an 80% increase in meantime between failures compared to traditional DCS control. The increased MTBF combined with the reduction in data transfers required, substantially increases reliability and availability. The overall reduction in network traffic (even with the increased device condition, status, and other data typically passed from fieldbus devices to the DCS) also increases network availability.

In addition to increasing availability and reliability, field-level control also increases flexibility. With basic loop control performed in the field devices, dedicated process controllers can be freed up to handle higher-level functions, such as advanced control and optimisation. Foundation Fieldbus allows for ‘dynamically instantiable function blocks’. This means that users can activate function blocks in different components of the system as required. In addition to basic PID control blocks, users also have access to a large library of other block types. These include switches, alarms, and so on.

Foundation Fieldbus adoption has skyrocketed over the past several years, particularly in the power and HPI industries. ARC estimates that the total market for fieldbus products and services is rapidly approaching a billion dollars. Users that actually implement the control in the field functionality, however, still represent a small minority.

In ARC’s view, the reason most users do not take advantage of control in the field is due to the perception that it compromises reliability and availability, and provides little direct economic impact or business value proposition to the manufacturing enterprise. The reality is far different.

Until recently, there had been no comprehensive study that proved the business value proposition of control in the field. Most of the evidence was anecdotal. The results of real world control in the field applications, however, show that control in the field can provide a path to single loop integrity and truly distributed control for many flow and pressure loops in a process plant or mill.

Recently, UK-based, Industrial Systems and Control (ISC, www.isc-ltd.com) released a study called, ‘Control in the Field: Analysis of Performance Benefits'. In a series of illustrative simulation studies, ISC determined that control in the field has the potential to offer improved control loop performance due to its ability to offer faster sample rates and shorter latencies in the read-execute-write cycle of a control loop. ISC examined the differences in timing and sequencing associated with control in the field versus a scheme employing control in the DCS to establish typical latencies and sample rates that limit control performance. ISC tested many different scenarios and process dynamics and the report outlines the results and corresponding benefits. While all control in the field loops can benefit from increased integrity, flexibility, and reliability, ISC found that control loop performance benefits can be quite significant in fast process loops.

Larry O’Brien, research director, Process Automation

Larry O’Brien
Larry O’Brien

Larry’s focus areas at ARC include process automation solutions, fieldbus networks, distributed control systems, and automation services. Larry tracks the market for process automation systems (PAS) and has authored the PAS market studies for ARC since 1998. He has also authored many other market research, strategy, and custom research reports on a range of automation-related topics. Larry, who has been with ARC since 1995, has a BA from the University of Massachusetts at Lowell.

Dick Hill, VP and GM, Manufacturing Advisory Services

Dick Hill
Dick Hill

Part of the management team at ARC, Dick is responsible for developing the strategic direction for ARC products and services. Dick covers advanced software business on a worldwide basis. Dick has over 30 years of experience in manufacturing and automation. As a process engineer, he gained experience in oil refinery operations and APC applications. Later, he expanded this knowledge of manufacturing solutions applied to other process industries. Dick, who has been with ARC since 1995, is a graduate of Lowell Technological Institute with a BS in Chemical Engineering. He has completed post-graduate courses in network technologies and relational database structures at Northeastern University.

For more information contact Larry O’Brien, ARC Advisory Group, (+1) 781 471 1126, [email protected], www.arcweb.com



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Beckhoff’s XPlanar boosts productivity in medical device assembly
Beckhoff Automation Fieldbus & Industrial Networking
The intelligent transport system, XPlanar from Beckhoff provided the basis for an innovative system concept allowing the specialists at Automation NTH to reduce the space requirement of an assembly machine for medical diagnostic devices by a factor of 10.

Read more...
Comprehensive solutions for the food and beverage sector
RS South Africa Fieldbus & Industrial Networking
RS South Africa is reinforcing its commitment to the country’s dynamic food and beverage sector, backed by a comprehensive portfolio of over 800 000 products, extensive technical expertise and end-to-end service capabilities.

Read more...
Case History 198: Cascade control overcomes valve problems
Michael Brown Control Engineering Fieldbus & Industrial Networking
A large petrochemical refinery asked me to perform an audit on several critical base layer control loops. This article deals with a problem found on a valve controlling the flow of fuel to a heat exchanger.

Read more...
Improved networking technology for fire and gas detection
Omniflex Remote Monitoring Specialists Fieldbus & Industrial Networking
Critical alarm and event management technology supplier, Omniflex has worked with the South African Nuclear Energy Corporation to upgrade equipment providing digital and analogue signals for its safety critical fire and gas alarm systems.

Read more...
PC-based control for fertiliser
Beckhoff Automation Editor's Choice Fieldbus & Industrial Networking
On a farm in the USA, valuable ammonia is extracted from slurry and processed into ammonium sulphate. NSI Byosis has transformed this complex process into a flexible modular system. This modular approach requires an automation solution with flexible scalability in both hardware and software, which this Dutch company has found in PC-based control from Beckhoff.

Read more...
Loop signature 28: Things to consider when tuning.
Michael Brown Control Engineering Editor's Choice Fieldbus & Industrial Networking
I was giving a course at a remote mine in the middle of the Namibian desert. We were discussing tuning responses, and as I always do on my courses, I mentioned that in my opinion ¼ amplitude damped tuning is not desirable, and is in fact not good.

Read more...
How industrial network design impacts ESG commitments
Omniflex Remote Monitoring Specialists Fieldbus & Industrial Networking
In safety-critical industries like nuclear, petrochemical and oil and gas, installing a new industrial cable network is an extremely complicated task. Gary Bradshaw, a director of industrial network specialist, Omniflex explains why this is often unnecessary as plants are likely to have existing cabling capable of being used to create new industrial networks.

Read more...
Minelert industrial solutions
Fieldbus & Industrial Networking
Profitek provides cutting-edge industrial networking, automation and IoT solutions for harsh environments.

Read more...
The ultimate industrial LoRaWAN gateway
Fieldbus & Industrial Networking
The GW-101-LORA-4AO is the ultimate industrial LoRaWAN gateway, combining advanced IoT connectivity with expandable I/O.

Read more...
Industrial Power-over-Ethernet DC injector
Fieldbus & Industrial Networking
The ML-NET-INJECT series sets the standard for industrial PoE, featuring IP68-rated RJ45 connectors and military-grade components for extreme reliability.

Read more...









While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.




© Technews Publishing (Pty) Ltd | All Rights Reserved