In today's competitive global marketplace, technology innovations must conform to changing business requirements in order to maximize the return on capital investments.
A case in point is the evolution of the Foundation fieldbus, which enables the migration of plants and factories to digital networks for process, discrete, and hybrid/batch solutions. Fieldbus technology not only takes advantage of today's intelligent instrumentation to provide reliable, deterministic control; it also reduces wiring requirements, reduces engineering and commissioning time and costs, and lowers installation and equipment costs.
Recently, the Fieldbus Foundation extended its fieldbus protocol with a High Speed Ethernet (HSE) implementation. Users with continuous and time-critical plant automation applications will be the main beneficiaries of this development. HSE, together with the Foundation H1 (31.25 kbit/s) fieldbus, provides a complete, complementary fieldbus solution: H1 fieldbus for continuous control, and HSE (100 Mbit/s) for high-speed process automation and hybrid/batch applications.
HSE was designed specifically to employ standard, low-cost Ethernet components and wiring, and can use fiberoptic media to run the network backbone through noisy or hazardous environments. Furthermore, the technology supports redundant communications paths and redundant devices for mission-critical monitoring and control applications. Although HSE was developed for control networks running at 100 Mbit/sec., it can support network speeds of 1 Gbit/sec. or higher, if needed.
So, in addition to serving as a control backbone, the HSE open network architecture enables integration of plant data servers such as those based on OLE for Process Control (OPC), and Microsoft's Distributed interNet Application (DNA) for manufacturing network architecture. This permits plant information to be available to Enterprise Resource Planning (ERP), Asset Management Systems (AMS), Data Warehouses, and other application software packages. The HSE Internet-based control integration solution also enables companies to interconnect manufacturing operations at different locations around the world.
The economic benefits of the integrated fieldbus architecture are significant for industrial manufacturers. Users can realize a direct cost savings from the technology in both operating expenditure (OPEX) and capital expenditure (CAPEX) reductions.
However, combining these two approaches requires a change in focus, since companies often consider the capital budget separately from the operational expenditure budget. When working with legacy systems, some approaches advocate cutting costs at the and capital expenditure stage alone. This is a mirror of previous methods and can make systems unwieldy and unbalanced, as well as expensive to maintain, enlarge, or modify.
A more comprehensive approach to network cost issues looks at the total picture and manages the installation and operation as a complete system. The application of HSE and H1 technologies now"and in the near future"rests at the nexus of the control backbone where disparate data systems intersect, and high speed is the answer to instrumentation response.
HSE took on the challenge for a unified control network solution by integrating H1 networks (via a linking device), disparate plant networks, and legacy control systems. It supports the entire range of Foundation fieldbus capabilities, including standard function blocks and Device Descriptions (DDs), and the new application-specific Flexible Function Block (FFB) for advanced process and discrete/hybrid/batch applications. FFBs were developed specifically for the HSE program, but are also compatible with H1 fieldbus systems. FFBs are configured using standard programming languages such as IEC 61131. Some control vendors provide pre-configured FFBs such as eight-channel analog or discrete multiple input/output (MIO) blocks. The MIO blocks can be used to integrate data from simple remote I/O networks and other subsystems into function blocks.
The use of FFBs enhances the ability to move control functionality to the field-level. For example, with FFBs running in a linking device, one physical device can support batch and logic control. With this approach, users can often eliminate the need for proprietary unit controllers.
In the area of safety, Fieldbus Foundation's open specification for Safety Instrumented Systems (SIS) will provide additional opportunities for increased integration and reduced costs. End users will have the freedom to choose certified instruments from multiple suppliers, instead of being restricted to devices designed specifically for a proprietary safety instrumented system.
End users, member companies, and technical team participants will determine the future direction of Foundation fieldbus technology. Results from current users and developers show a clear trend: matching the true value of OPEX and CAPEX benefits to the sum total extraction of asset management, life extension and reductions in downtime.
Joe Conklin is a marketing specialist with the Fieldbus Foundation (www.fieldbus.org). He holds a BS in Computer Science and Strategic Planning and has more than 20 years of technical marketing and systems experience in the automation industry.
