The IEEE 1451, a family of Smart Transducer Interface Standards, describes a set of open, common, network-independent communication interfaces for connecting transducers (sensors or actuators) to microprocessors, instrumentation systems, and control/field networks. The key feature of these standards is the definition of Transducer Electronic Data Sheets (TEDS). The TEDS is a memory device attached to the transducer, which stores transducer identification, calibration, correction data, measurement range, and manufacture-related information, etc. The goal of 1451 is to allow the access of transducer data through a common set of interfaces whether the transducers are connected to systems or networks via a wired or wireless means. The family of IEEE 1451 standards are sponsored by the IEEE Instrumentation and Measurement Society's Sensor Technology Technical Committee chaired by Kang Lee.
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IEEE 1451.0 * defines a set of common commands, common operations, and TEDS for the family of IEEE 1451 smart transducer standards. Through this command set, one can access any sensors or actuators in the 1451-based wired and wireless networks. The functionality is independent of the physical communications media between the transducers and the network node called Network Capable Application Processor (NCAP). This makes it much easier to add other proposed 1451.X physical layers to the family as technology advances in the future.
IEEE 1451.1 *** defined a common object model describing the behavior of smart transducers. It defines a measurement model that streamlines measuremnt processes. It also defined the communication models used for the standard, which included the client-server and publish-subscribe models. Application software running in the NCAP based on IEEE 1451 communicated with transducers through the different IEEE 1451.X physical layer standards as required for a particular application. Communications among NCAPs and to higher level systems are supported in a network neutral manner.
IEEE 1451.2 *** defined a transducers-to-NCAP interface and TEDS for a point-to-point configuration. Transducers are part of a Transducer Interface Module (TIM). The original standard describes a communication layer based on enhance SPI (Serial Peripheral Interface) with additional HW lines for flow control and timing. This standard is being revised to add support for the popular serial UART interface.
IEEE 1451.3 defined a transducer-to-NCAP interface and TEDS for multi-drop transducers using a distributed communications architecture. It allowed many transducers to be arrayed as nodes, on a multi-drop transducer network, sharing a common pair of wires.
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IEEE 1451.4 *** defined a mixed-mode interface for analog transducers with analog and digital operating modes. A TEDS was added to a traditional two-wire, constant current excited sensor containing a FET amplifier. The TEDS model was also refined to allow a bare minimum of pertinent data to be stored in a physically small memory device, as required by tiny sensors. Templates are used to describe the data structure of TEDS. The current templates cover acclerometers, strain gages, current loop sensors, microphones, thermcouples,and more.
IEEE 1451.5 * defines a transducer-to-NCAP interface and TEDS for wireless transducers. Wireless communication protocol standards such as 802.11 (WiFi), 802.15.1 (Bluetooth), 802.15.4 (ZigBee) are being considered as some of the physical interfaces for IEEE P1451.5. One should be able to get the same sensor data from the wireless sensor implementing any of these three wireless protocols.
IEEE P1451.7 * proposed standard for a Smart Transducer Interface for Sensors and Actuators - Transducers to Radio Frequency Identification (RFID) Systems Communication Protocols and Transducer Electronic Data Sheet Formats, describes communication methods, data formats and provides a Transducer Electronic Data Sheet (TEDS) for sensors working in cooperation with Radio Frequency Identification (RFID) systems. This document does not outline, recommend, or prescribe to any specific air-interface protocol. This document is intended to be air-interface agnostic.
* The proposed standard is being developed.
TEDS=Transducer Electronic Data Sheet |
A copy of these standards in publication or released draft specifications can be ordered on the IEEE website http://standards.ieee.org/sds/index.html, or from IEEE by calling 1-800-678-4333 (in US and Canada) or 1-732-981-0600 (outside US and Canada) or by fax 1-732-981-9667.