Criteria for Design and Specification

1. Criteria for Design and Specification NeSSI IssuesPresentation to IFPAC Regarding NeSSI Generation 2 Bus January, 29, 2008Bob Farmer

2. Topics • Overview; terminology • Design criteria • System issues • Bus and cabling • Components • Product and marketing issues

3. T V P A Basic Bus Configuration and System Concept Controlling Unit (SAM) B B B B

4. T V P A Extended System Concept Controlling Unit (SAM) ? B B B B AC Power ? DC Power

5. T V P A Extended System Concept Ambient Environment Cabinet System Environment Controlling Unit (SAM) B B B B B B AC Power DC Power

6. Bus including drivers and power source Bus Definition Substrate Definition Point of Bus Interface Point of Substrate Interface NeSSI Substrates Component Electrical Implementation Bus electronics; Intrinsic Safety barriers; and Standardized interface to component electronics SAM – including Bus source and software Proprietary component-specific electronics by component vendor Proprietary mechanical NeSSI component by component vendors Assembly and certification of the complete component

7. Design Criteria • System • Bus and Cable • Components

8. System Design Criteria • Overall system configuration and size • Minimum • Typical • Maximum • Ambient environment • Impact on bus external to system enclosure • System environment • Impact on bus internal to system enclosure • Impact on components and devices in system • Component capabilities and requirements • Power issues • Native capabilities and implementation methods regarding safety concerns • Market volume: available development resource commitment and impact on bus interface development

9. Bus Design Criteria Power Requirements: Sensors: 10-40ma Controllers: 20-70ma Valve pilots: 80-350ma • Capacity • Number of devices • Types of devices • Participating suppliers • Physical Issues / Installation • IP ratings / protection • Ambient conditions • Certifications / safety • Chemical resistance • Electrical • Length • Installed base / compatibility • Load capacity / load management • Power distribution • Interruption / interchange • Reliability / EMI / RFI • Instances / continuity • Software • Device representation • Device function • Maintenance issues • Configuration / addressing / identity Number of components on bus: Typical: 5-15 Common: 20-30 Maxum: 200 Design goal for flammability ignition temperature to be T4 (135°C) with minimum at least T3 (200°C). Component ambient temperature to be >=70°C Capability for the standard functions to be implemented in a variety of ways.

10. Cabling Issues • Cable size, bend radius, height • Connection methods and system design • Jacket materials • Cost

11. Component Design Criteria • Primary component performance • Physical size and shape • Mounting constraints • Power consumption • Diagnostic support • Ambient and physical ratings (see also Bus and Cabling) • Chemical and atmospheric tolerance (see also Bus and Cabling)

12. Other Product Marketability Issues • System responsibility • Supplier: Integrator, component manufacturer, bus provider • System elements: Bus master, components, cables and peripherals • Field support • Training • Configuration and implementation difficulties • Issues with interchangeability • Spare parts and long term support • Field diagnosis and repair plan • Component support life: longevity in a “capital” investment versus short life span of electronic and software techniques

13. Questions - Discussion