IEEE 1451.3

Abstract

Foreword<br>The main objectives of this standard are to:<br>&#8212; Enable plug and play at the transducer level by providing a common communication interface for transducers which are physically separated<br>&#8212; Enable and simplify the creation of groups of networked smart transducers<br>&#8212; Facilitate the support of multiple networks <br>The existing fragmented sensor market is seeking ways to build low-cost, networked smart sensors. Many sensor network or fieldbus implementations are currently available, each with its own strengths and weaknesses for a specific application class. Interfacing transducers to all these control networks and supporting the wide variety of protocols represents a significant and costly effort to transducer manufacturers. A universally-accepted transducer interface standard would not only allow for the development of smart sensors and actuators, it could also lead to lower development costs. Therefore, the goal of this standard is not to propose another control network, but to define a smart transducer interface that will isolate the choice of transducers from the choice of networks. This would relieve the burden from the manufacturer of supporting a cross product of sensors versus networks, and would help to preserve the user&#8217;s investment if it becomes necessary to migrate to a different network standard. <br>There is currently only the IEEE Std 1451.2^TM-1997^a common digital communication interface standard between transducers and Network Capable Application Processors (NCAPs). IEEE Std 1451.2-1997 supports transducers that can be physically included within one housing, but it does not support transducers that are physically separated but need to make their network connection through a single NCAP. IEEE Std 1451.2-1997 does, however, provide a comprehensive set of TEDSs that are the basis for the TEDS described in this document. Care has been taken throughout the development of this standard to modify the IEEE Std 1451.2-1997 TEDS only as required to meet different requirements of the different environment and to provide for a translation path between the IEEE Std 1451.3-2003 TEDS and the IEEE Std 1451.2-1997 TEDS.<br>IEEE Std 1451.3-2003 utilizes the techniques designed to implement networking in the home by interconnection devices on the telephone lines. For IEEE Std 1451.3-2003, a single pair of conductors will be used to provide the following functions:<br>&#8212; synchronized data acquisition for an array of transducers<br>&#8212; communicating with an array of Transducer Bus Interface Modules (TBIM)<br>&#8212; providing power for operation of transducers on the bus and their associated electronics <br>Transducers built per this standard can be plugged into an IEEE Std 1451.3-2003 compatible system and be used without having to add special drivers, profiles or make any other changes to the system. The IEEE Std 1451.3-2003 TEDS provides for self-identifying transducers. The TEDS contains fields that fully describe the type, operation, and attributes of one or more transducers (sensors or actuators). By having the TEDS associated with the transducer and module containing the transducer, the resulting hardware partition encapsulates the measurement aspects to a module. The application related aspects of the measurement are on the bus controller or NCAP and do not become a concern for the transducer manufacturer.<br>Data output over the bus may be in integer; single precision real or double precision real formats. The data is passed to the bus controller and from the bus controller to the rest of the system. Further processing of this data may take place both in the bus controller and in other processors in the larger system. Throughout this document it is assumed, but not required, that all processing will be performed on data in a single or double precision real format. All fields in the TEDS are specified based on the assumption that, unless specifically stated to the contrary, all data will be converted to single or double precision real before any processing is performed.<br>This standard provides areas that are &#8216;&#8216;open to manufacturers.&#8217;&#8217; It should be noted that any use of these areas compromises the &#8216;&#8216;plug and play&#8217;&#8217; potential of bus controllers and TBIMs.<br>The IEEE Std 1451.3-2003 transducer interface is adaptable to the IEEE Std 1451.2-1997 interface and compatible with the IEEE Std 1451.1^TM-1999 information model standard. <br>Scope<br>This standard defines a digital interface for connecting multiple physically separated transducers. It leverages off the IEEE Std 1451.1^TM-1999 and IEEE Std 1451.2^TM-1997 standards. This standard defines the TEDS format, the electrical interface, channel identification protocols, hot swap protocols, time synchronization protocols, and the read and write logic functions used to access the TEDS and transducer data. This standard does not specify signal conditioning, signal conversion, or how an application uses the TEDS data.