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Contact:
Kang Lee

General Information:
301 975 6602 Telephone
301 990 3851 Facsimile

100 Bureau Drive,
M/S 8220
Gaithersburg, MD 20899-8220

P1451.1 Working Group

Traditional transducer manufacturers have to spend a large development effort interfacing their sensors or actuators to a control network. Usually the results of one network development effort can not be easily transported to other networks. This situation causes a major problem for transducer manufacturers nationwide, most are small companies, which have limited R&D investment and experience with the latest sensor-networking technology. A common network-independent application model mapping to any sensor/actuator network protocol will reduce the effort for interfacing smart sensors and actuators to control networks. It will establish interoperability between sensors/actuators and existing control networks, thus enabling "plug and play" capability. A standard object model will simplify the support of multiple sensor/actuator network protocols.

transducers

Figure 1: Networked Transducer

This project, designed as P1451.1, Standard for a Smart Transducer Interface for Sensors and Actuators - Network Capable Processor Information model, is to develop a standardized software interface for connecting network-capable application processors (NCAPs) to control networks. Standardization will be achieved through the development of a common control network information or object model including: transducer block, function block, and network block along with their underlying structures.

The common information model will be complimentary, not competitive, to any existing object models. This project will not define individual device algorithms or specifications of what is> implemented using the model.

The objective of the IEEE Working Groups is to develop standardized connection methods for smart transducers to control networks. Figure 1 shows a typical device network and transducers.

This objective is achieved through the definition of common object models for the transducer and for the networked smart transducer, together with interface specifications to these models. Figure 2, Networked Smart Transducer Model, shows the views of the networked smart transducer.

Networked Smart Transducer Model P1451.1 

Figure 2: Networked Smart Transducer Model P1451.1

The first view shows the physical components of the system. This is indicated by components drawn with solid lines. It shows a model composed of sensors and actuators connected to some interface electronics to form a small Transducer Interface Module (STIM). The STIM is connected over an interface to a microprocessor or controller that is in turns interfaced to the network. The hardware interface specification between the sensor/actuator and the rest of the device hardware, is indicated by the rightmost thick, vertical dashed line in the figure. This specification is described in the standard IEEE std1451.2 - 1997, which can be obtained from IEEE.

The logical view of the system is shown by the dotted components. The IEEE Transducer Interface Specification encapsulates the details of the hardware implementation within a simple programming model, that makes the sensor or actuator interface look like an i/o-driver. This logical model and interface specification is used by the IEEE Network Interface Specification in defining a data model for the smart transducer that is supported by the network. This specification models the behavior of the smart transducer as a "software card-cage" into which modules of functionality can be plugged, and using simple handshaking mechanisms can interact with each other. The logical (io-driver) interface is indicated by the middle dashed line, and the data model interface between the smart transducer and the network is indicated by the leftmost dashed line.

Status: The IEEE P1451.1 draft was approved by IEEE Standards Board as a full-use standard with a designation of IEEE