Foundation Fieldbus Author Dominique Egloff Class E4p Lecturer Max Felser Date

Transcription

1 Foundation Fieldbus Author Dominique Egloff Class E4p Lecturer Max Felser Date

2 1 Table of contents 1 TABLE OF CONTENTS BRIEFING MISSION ADVANTAGES OF FOUNDATION FIELDBUS HISTORY ORIGINS OF THE TECHNOLOGY CONSENSUS IN THE INDUSTRY MARKET AND APPLICATION AREA RAPID GROWTH IN THE MARKET PROMISING OUTLOOK FOR THE FUTURE APPLICATION MODEL H HSE A KEY TECHNOLOGY FOR ENTERPRISE INTEGRATION DESIGNED TO SUPPORT MISSION-CRITICAL APPLICATIONS TECHNOLOGY INSTALLATION SOURCES...11 Foundation Fieldbus.doc 1 / / EgD

3 2 Briefing 2.1 Mission The Fieldbus Foundation is a not-for-profit corporation consisting of over 350 leading process and manufacturing automation companies worldwide whose major purpose is to provide an open and neutral environment for the development of a single, international, interoperable fieldbus. In this environment, end users, manufacturers, universities and research organizations are working together to develop the technology, provide development tools, support and training, coordinate field trials and demonstrations, and enable product interoperability. 2.2 Advantages of Foundation Fieldbus From a business standpoint, FOUNDATION technology delivers savings in total installation costs. H1 fieldbus reduces instrument wiring, which means less termination and fewer screwdriver turns. The technology reduces hardware requirements and lowers Capital Expenditures. FOUNDATION fieldbus primarily reduces Operating Expenses through improved plant efficiencies, better asset management, and reduced maintenance requirements. Specific benefits of FOUNDATION technology include: reduced wiring, multi-variables from a single multi-channel field instrument, simpler integration and easier maintenance. Ultimately, FOUNDATION technology will be the key to greater manufacturing flexibility and productivity, higher quality products, and improved regulatory compliance. This can be achieved by predictive maintenance scheduling and better upkeep enabled by the diagnostics, performance analysis data, and operational statistics. Better adjusted and properly calibrated devices ensure lower process variability. The isochronous bus cycle enables tighter loop tuning, and as a result, better process control. Firmware download gives the ability to stave off obsolescence, giving fieldbus plants longer life than other plants with greater ease. FOUNDATION H1 is the only digital fieldbus protocol developed to meet the original IEC requirements. Unlike other protocols, FOUNDATION H1 provides explicit synchronization of control and communication for precisely periodic (isochronous) communication and execution of control functions with minimized dead time and jitter. It synchronizes clocks in fieldbus devices for support of Function Block scheduling and alarm time-stamping at the point of detection. Additionally, FOUNDATION H1 provides automatic address setting, eliminating the need to manually set addresses off-line using a tool or DIP switches and avoiding subsequent mistakes. FOUNDATION H1 uses peer-to-peer communication where devices communicate directly using a publisher/subscriber communication relationship enabling data to be sent to several devices in a single message thus reducing overhead. FOUNDATION H1 includes alarm and event reporting for efficient diagnostics and process alarms. Online firmware download makes it possible to upgrade devices in order to stay ahead of the obsolescence curve. Lastly, a rigorous interoperability testing program ensures quality connectivity. Foundation Fieldbus.doc 2 / / EgD

4 3 History 3.1 Origins of the technology The path to fieldbus technology began in the 1970s with the first attempts to distribute control functionality to the field level. With the introduction of the Distributed Control System (DCS), processing plants were able to distribute intelligent control throughout process facilities. At the time, field devices had little, if any, communication with each other and sent minimal data to the DCS. Most devices communicated to controllers using pneumatic or 4-20 ma analog signals. Real process information was limited and often obtained through interpolation, inference and/or expensive gateways and proprietary data acquisition implementations. The complexity and cost to obtain data was high and far removed from real-time. In the 1980s, considerable effort went into developing a digital communication standard for field devices. Credit is due those members of the ISA's SP50 committee who spent years defining technical requirements and building consensus for a digital fieldbus. In the interim, leading process control suppliers started work on their own proprietary digital communication standards. These multiple efforts resulted in a handful of competing protocols, none of which could work together. 3.2 Consensus in the industry In late 1994, the path of fieldbus took a new, promising direction. Two parallel supplier consortiums-the InterOperable Systems Project (ISP) and WorldFIP North America-merged to form the Fieldbus Foundation. The new organization immediately brought critical mass to the effort to achieve an internationally acceptable fieldbus standard. The foundation organized development programs, conducted field trials, and established the industry's most rigorous program for testing and registration of fieldbus devices. Working arm-in-arm, manufacturers, end users, academic institutions and other interested parties became members of the Fieldbus Foundation and developed open, non-proprietary specifications known as FOUNDATION fieldbus. This advanced digital communication solution was designed from the ground-up to support mission-critical control applications where the proper transfer and handling of data is essential. FOUNDATION technology was created to replace incompatible networks and systems with an open, fully integrated architecture for information integration and distributed, real-time control across the enterprise. With FOUNDATION technology, users gained the power to implement tightly integrated digital control based on a unified system architecture and a high-speed backbone for plant operations. This, in turn, removed the previously experienced constraints on device and subsystem interoperability. Foundation Fieldbus.doc 3 / / EgD

5 4 Market and application area 4.1 Rapid growth in the market In little more than a decade, the Fieldbus Foundation's technology has achieved industry standard status among process end users. Implementation of the Foundation system architecture is growing at a rapid pace in diverse industries across the globe. Consider the following: The Fieldbus Foundation has now tested and registered nearly 250 fully interoperable fieldbus devices. 16 host systems have successfully completed the foundation's Host Interoperability Support Test (HIST). More than 700,000 Foundation-compliant devices and 10,000 fieldbus systems have been shipped or installed to date. Successful Foundation technology installations can be found in industries such as petrochemical, refining, chemical, oil & gas, metals & mining, water & waste, pulp & paper, utilities, food & beverage. To support the user community, the Fieldbus Foundation has established End User Councils (EUCs) in locations worldwide. 4.2 Promising outlook for the future To keep pace with industry requirements and protect users' investments in its technology, the Fieldbus Foundation is undertaking a series of exciting new initiatives that will take the Foundation system architecture well into the 21st century. For example, the Fieldbus Foundation, HART Communication Foundation and PROFIBUS Nutzerorganisation e.v. have formed a joint working group which is expanding the capabilities of Electronic Device Description (EDD) technology. The working group developed extensions enabling robust organization and graphical visualization of device data, and providing support for persistent data storage. The extensions were made available to all three organizations to integrate within their respective control network protocols. The Fieldbus Foundation has also developed Foundation fieldbus Technical Specifications- Safety Instrumented Systems (SIS) supporting the design and end user implementation of safety technology compliant with IEC guidelines. The Foundation architecture, with its industry-proven distributed function blocks and open communications protocol, is an ideal platform for advancing standards-based safety system technology. Fieldbus Foundation members developed SIS specifications and guidelines in cooperation with the world's leading safety experts. The Foundation fieldbus Technical Specifications-Safety Instrumented Systems will enable end users to take advantage of open fieldbus technologies to improve integration and interoperability of safety instrumentation, while reducing system and operational costs such as annual shutdowns for test and validation purposes. The future is bright for the process automation industry, as end users around the world take advantage of the many performance improvements-and business benefits-delivered by Foundation technology. Foundation Fieldbus.doc 4 / / EgD

6 5 Application model The open, nonproprietary Foundation architecture provides a communications protocol for control and instrumentation systems in which each device has its' own "intelligence" and communicates via an all-digital, serial, two-way communications system. 5.1 H1 Foundation H1 is intended primarily for process control, field-level interface and device integration. Running at kbit/s, the technology interconnects devices such as transmitters and actuators on a field network. H1 is designed to operate on existing twisted pair instrument cabling with power and signal on the same wire. Fiber optic media is optional. It also supports Intrinsic Safety (IS) applications. FOUNDATION H1 devices comprise a function block application, act as a publisher and subscriber of process variables, transmit alarms and trends, and provide server functionality for host access and management functions. Devices can act as a scheduler and time master for regulating communication on a fieldbus segment. They are also used for bus interfaces in process control systems or in linking devices. Capable of controlling bus communications and many connections to multiple devices, they support both client and server applications. H1 technology enables field instruments and other devices to execute control functions reducing the load on plant computers and workstations. Since the H1 network is digital, I/O conversion subsystems are eliminated. The Fieldbus Foundation tests and registers the devices to ensure interoperability of registered instruments from multiple vendors. This enables the end user to select the best instruments for the application regardless of the host system supplier. Reports from leading adopters of the FOUNDATION protocol demonstrate the advantages of control in the field with the H1 solution. For example, end users in the petrochemical industry have realized up to a 30 percent reduction in operating costs due to advanced diagnostics. Users have also seen that the all-digital H1 communications network is far less susceptible to electrical noise than traditional 4-20 ma analog systems. H1 technology enjoys widespread acceptance throughout the process industries, and is included in the international IEC standard (IEC 61158). Foundation Fieldbus.doc 5 / / EgD

7 5.2 HSE High Speed Ethernet (HSE) is ideally suited for use as a control backbone. Running at 100 Mbit/s, the technology is designed for device, subsystem and enterprise integration. It supports the entire range of fieldbus capabilities, including standard function blocks and Device Descriptions (DDs), as well as application-specific Flexible Function Blocks (FFBs) for advanced process and discrete/hybrid/batch applications. HSE supports complex logic functions, such as those performed by Programmable Logic Controllers (PLCs), or data-intensive process devices, such as analyzers and gateways to other networks. HSE enhances access to H1 fieldbus technology via linking devices, while providing expanded capabilities for high-speed automation devices and hybrid/batch applications A key technology for enterprise integration HSE enables tight integration and a free exchange of information needed for the plant enterprise. HSE is a superior solution to proprietary, Ethernet-based technologies since it provides end users with interoperable devices from multiple suppliers. And like H1, HSE is an international standard (IEC 51158). HSE provides the same benefits as H1, but at the subsystem integration level instead of the field device level. It supports interoperability between disparate controllers and gateways in the same way that H1 supports interoperability between transmitters and actuators from different suppliers. FFBs in HSE devices can be set up using programming languages such as those found in the international standard IEC Designed to support mission-critical applications HSE technology was designed from the ground-up to support fault-tolerant networks and devices used in mission-critical monitoring and control applications. All or part of the HSE network and devices can be made redundant to achieve the level of fault tolerance required for a particular application. Best of all, redundancy is supported using standard Ethernet equipment, thus eliminating the cost of special network equipment. HSE also supports standard Ethernet wiring, including a fiber optic media option to provide costeffective electrical isolation between plant areas or immunity from distortion through noisy environments. Foundation Fieldbus.doc 6 / / EgD

8 6 Technology The FOUNDATION protocol is designed to be compatible with the officially sanctioned SP50 standards project of the ISA, as well as and the specifications of the International Electrotechnical Committee (IEC). Since its founding, the Fieldbus Foundation has made compliance with the ISA/IEC standards a priority. The IEC voted to include the FOUNDATION HI and HSE specifications in the IEC international standard. The CENELEC Technical Bureau added the FOUNDATION H1 specifications to EN Euronorm. In addition, FOUNDATION technology is the only implementation of the ANSI/ISA standard. The FOUNDATION specifications are also compliant with IEC (Function Blocks for Process Control and Electronic Device Description Language) and IEC (Functional Safety of Electrical/Electronic/ Programmable Electronic Safety-related Systems). Both NAMUR (Germany) and JEMIMA (Japan) have voiced support for FOUNDATION technology, and provided input from the end user community that aided in specification development. Approval and support by key international industry bodies gave users the confidence that their investments in FOUNDATION-compliant solutions were based on recognized global standards and sound best practices from industry groups. The FOUNDATION specification is based on the ISO/OSI layered communications model, and consists of three major functional components: the Physical Layer, the communication "stack," and the User Layer. The Physical Layer corresponds to OSI Layer 1, which receives encoded messages from the upper layers and converts the messages to physical signals on the fieldbus transmission medium and vice-versa. The communication "stack" corresponds to Layers 2 and 7 in the OSI model. Layer 7, the Application Layer (AL), encodes and decodes User Layer commands. Layer 2, the Data Link Layer (DLL), controls transmission of messages onto the fieldbus through Layer 1. The DLL also manages access to the fieldbus through a deterministic, centralized bus scheduler called the Link Active Scheduler (LAS). The LAS is used for scheduling transmissions of deterministic messages and authorizing the exchange of data between devices. The fieldbus does not use the OSI Layers 3, 4, 5 and 6. Foundation Fieldbus.doc 7 / / EgD

9 The IEC voted to include the FOUNDATION HI and HSE specifications in the IEC international standard. The CENELEC Technical Bureau added the FOUNDATION H1 specifications to EN Euronorm. In addition, FOUNDATION technology is the only implementation of the ANSI/ISA standard. The FOUNDATION specifications are also compliant with IEC (Function Blocks for Process Control and Electronic Device Description Language) and IEC (Functional Safety of Electrical/Electronic/ Programmable Electronic Safety-related Systems). Both NAMUR (Germany) and JEMIMA (Japan) have voiced support for FOUNDATION technology, and provided input from the end user community that aided in specification development. Approval and support by key international industry bodies gave users the confidence that their investments in FOUNDATION-compliant solutions were based on recognized global standards and sound best practices from industry groups. The FOUNDATION specification is based on the ISO/OSI layered communications model, and consists of three major functional components: the Physical Layer, the communication "stack," and the User Layer. The Physical Layer corresponds to OSI Layer 1, which receives encoded messages from the upper layers and converts the messages to physical signals on the fieldbus transmission medium and vice-versa. The communication "stack" corresponds to Layers 2 and 7 in the OSI model. Layer 7, the Application Layer (AL), encodes and decodes User Layer commands. Layer 2, the Data Link Layer (DLL), controls transmission of messages onto the fieldbus through Layer 1. The DLL also manages access to the fieldbus through a deterministic, centralized bus scheduler called the Link Active Scheduler (LAS). The LAS is used for scheduling transmissions of deterministic messages and authorizing the exchange of data between devices. The fieldbus does not use the OSI Layers 3, 4, 5 and 6. Foundation Fieldbus.doc 8 / / EgD

10 7 Installation In figure 6.1 we see a Fieldbus Network with some field devices. The new devices are simply connected in parallel with the first field device. The new devices are shown connected in a star fashion. However, they could also be chained from the first device as in figure 6.2. Fig.6.1 Fig.6.2 You can see that new devices are always added in parallel to existing ones. Notice that the number of terminators in figure 6.1 and 6.2 stays at two, regardless of what else we add to the network. We can add to the network by tapping into the trunk at any point or by extending it. Suppose we want to add a field device near the middle of the trunk of figure 6.2, and a bridge to a highspeed network at the FFI end. The result might be that of Figure 6.3. Notice that the terminator at the FFI end has been moved to the new end of the trunk. We can have a total of 32 devices on each segment of a network (even more with repeaters), with some restrictions. One restriction is the total wire pair length in a given segment. This is the sum of the trunk length and spur lengths. In Figure 6.3 we ve assigned some length numbers to the network. This total is limited according to the type of cable used. See Figure 6.4 for a summary of length versus type of cable. Another restriction is spur length. If you have a choice about the length of a spur, shorter is better. The total spur length is limited according to the number of spurs and number of devices per spur. This is summarized in Figure 6.5. Foundation Fieldbus.doc 9 / / EgD

11 Fig.6.3 Fig.6.4 Fig.6.5 Foundation Fieldbus.doc 10 / / EgD

12 8 Sources Informations are all from You find an installation guide to download under End User Recources -> Technical References for further informations. Foundation Fieldbus.doc 11 / / EgD