Brief Description of the Family of IEEE 1451 Standards

IEEE P1451.0 * 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 measurement 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.  

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 P1451.5 * 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 P1451.6 * defines a transducer-to-NCAP interface and TEDS using the high-speed CANopen network interface. Both intrinsically safe and non-intrinsically safe applications are being supported. It defines a mapping of the 1451 TEDS to the CANopen dictionary entries as well as communication messages, process data, configuration parameter, and diagnosis information. It adopts the CANopen device profile for measuring devices and closed-loop controllers.

* The proposed standard is being developed.
** The proposed standard has been balloted and is awaiting publication.
*** The standard is in publication and can be acquired at the IEEE.org web site.

TEDS=Transducer Electronic Data Sheet
NCAP=Network Capable Application Processor
STIM =Smart Transducer Interface Module