Integration of information from sensors, automatic process and discrete control systems, supervisory and batch systems, resource planning systems and management information systems is required for plant optimization. The primary barrier to integration in the past was the lack of open specifications for the fieldbus system used for interconnecting the automation equipment.

Open specifications enable control devices from different manufacturers to interoperate on the same network without the need for custom programming. The specifications must include the communications system and the "user layer" above the communication system. The communication system simply moves data from point A to point B. It is the User Layer that enables distribution of control functions into control devices and provides for a common "function block" language.

FOUNDATION fieldbus provides open specifications for a 31.25 kbit/s fieldbus (H1) and a 100 Mbit/s fieldbus called High Speed Ethernet (HSE).

H1 is optimized to handle distributed process control applications. The H1 physical layer signaling, data link and messaging protocols are specified in the approved ISA SP50 and IEC 61158 standards. The User Layer specification provides the function blocks and device descriptions necessary for interoperability at the control strategy level. The User Layer specifications have been released by the Fieldbus Foundation.

HSE running at 100 Mbit/s is designed for advanced hybrid, batch and manufacturing applications. Linking devices are used to interconnect multiple H1 fieldbus segments to HSE. A "Flexible Function Block" (FFB) implements control strategies based on programming standards such as IEC 61131. FFBs support such functions as supervisory data acquisition, I/O subsystem interfaces, sequence of events and coordinated drives. They also allow multiplexers, PLCs and gateways to other protocols to use the HSE backbone.

HSE physical layer signaling and data link protocols are specified in IEEE 802.3 and ISO/IEC 8802-3 standards. HSE uses standard Internet protocols including TCP/IP, UDP, and SNTP. The use of standard Ethernet/Internet protocols allows HSE fieldbus networks to be built using Commercial off the Shelf (COTS) Ethernet cable, switches and routers. HSE supports fault-tolerant networks and redundant HSE devices for mission-critical monitoring and control applications. Using standard Ethernet wire and fiber optic media, fault-tolerent HSE control networks of any topology or size can be created.

H1 fieldbus combined with linking devices, gateways and fault tolerance, make the Fieldbus Foundation's HSE technology well-suited as the plant control backbone. HSE's bandwidth capabilities enable the transfer of large files and support of high speed I/O such as analyzers and PLCs. Moreover, its use of standard fieldbus function blocks, such as AI, AO and PID, and the FFB, ensures a uniform presentation of data at all levels of the control network.

Mr. Dave Glanzer is the Director of Technology Development at the Fieldbus Foundation (Austin, TX). He is responsible for development of the foundation's technology-based specifications and products, worldwide.

Mr. Glanzer has over 20 years of experience in automation systems design and new product development. His broad background also includes strategic information systems planning and leadership of ISO 9001 quality programs.

Mr. Glanzer served as the Project Services Manager for the H1 Specification Project, including development and release of the foundation's Registration Test Tools and methodology. He served as a member of the Management Team which released the HSE Specifications in May 2000, and is currently leading development of additional HSE Specifications and Profiles for high speed applications.

Mr. Glanzer is a high honors BSEE graduate with specialization in digital circuits and semiconductor technology. He is a Member of the American Society for Quality (ASQ), and is a Senior Member of the International Society for Measurement and Control (ISA).