Industrial Network Track: Multi-Bus GarrettCom, Inc. 47823 Westinghouse Drive Fremont, CA 94539 PH: (510) 438-9071 FAX: (510) 438-9072 www.GarrettCom.
Industrial Network Track: Multi-Bus Author Jim W. Hammond – Technical Consultant, GarrettCom, Inc. Keywords: Network integration, Ethernet, TCP/IP, field buses, topology Last time I checked it was reasonably easy to get a bus transfer in NYC, but don’t expect that level of ease when doing transfers from one industrial bus to another. More than likely you’ll get more attitude than a rush hour bus driver.
If you’ve never seen the OSI model, avert your eyes from the following diagram. Too late. It’s not possible to read any book on data communications and networking and avoid seeing this conceptual view of a generic network architecture. Fortunately, we 7-Application will spend most of our time in layers one and two, which is where Ethernet operates. 6-Presentation 5-Session To clarify terms, the physical layer deals with the transmission and synchronism of data and physical interface definition.
Profibus is supported by Siemens and has a large presence in Europe with three protocol variations. It supports various media and topologies at speeds up to 12Mbit/s. The PROFINET spin-off is discussed later. Foundation Fieldbus is a special case that straddles proprietary and open standards. It uses OSI terminology to define its architecture and offers a wide range of topology and speed variations in its H1 definition, and uses high speed Ethernet (HSE) for its H2 definition.
SUMMARY The open standard networks support multiple topologies over Ethernet at speeds of 100Mbit/s or better and provide TCP and UDP interfaces. This should make clear the evolution to high speed Ethernet over a variety of topologies. INDUSTRIAL ETHERNET Industrial Ethernet supports the integration of existing sub-networks into a homogeneous network that includes effective routing, redundant links, and beefed up security. Many Ethernet vendors offer products designed for industrial environments.
Integrated Substation Network NETWORK INTEGRATION The hard choices of integration include decisions of how to connect to proprietary systems. This will vary from industry to industry. Most legacy systems that continue to perform well are candidates for some form of gateway interface unless local management elements are fully effective or isolation from other networks is desirable.
• • Integration: The ability to manage a large network from central or distributed locations, economies of scale, network visibility, and other factors without time-consuming testing of incompatible interfaces can provide huge benefits. VLAN support: The ability to define virtual networks for managing traffic and security. GATEWAYS Gateways make communications possible between dissimilar systems.
USING ETHERNET TO NETWORK There are many ways Ethernet components and standards can be employed to provide redundancy, robustness, security, and flexibility of design for many industrial networks. As has already been mentioned, Ethernet is also the best integration strategy available to network planners and architects. TOPOLOGY AND REDUNDANCY Ethernet works with star, bus, mesh, and ring topologies insuring the right topology for the job is selected.
interface (CLI) sent to the target component. Using the Secure Socket Layer (SSL) protocol over HTTPS connections provides the same level of security enjoyed by Web-based financial transactions. Simple Network Management Protocol version 3 (SNMPv3) limits access to sensitive Ethernet switches that feature SNMPv3 agent software/firmware. Data and operational control functions require user authentication, with access only permitted by specific IP addresses. Each IP address is configured during initial set-up.
SUMMARY ON BUS STRATEGIES There are two reasons to maintain proprietary buses: legacy systems that are still providing satisfactory service, and highly tuned and specific applications. However, in a world where costs, high availability, and future-proofing are key operational objectives, industrial Ethernet is the clear winner for new deployments.
