IEEE 1451 FAMILY OF SMART TRANSDUCER INTERFACE STANDARDS

 

 

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 a TEDS. The TEDS is a memory device attached to the transducer, which stores transducer identification, calibration, correction data, and manufacture-related information. 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 (kang.lee@nist.gov).

 


IEEE P1451.0 * defines a set of common operations and TEDS for the family of IEEE 1451 smart transducer standards. The functionality is independent of the physical communications media between the transducer and NCAP. This makes it easy to add other proposed 1451.X physical layers to the family.

 

IEEE 1451.1 *** defined a common object model and programming paradigm for smart transducer systems. This software runs on the NCAP and interacts with transducers through the other 1451.X physical layers standards. Communications between groups of NCAPs and 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 STIM. The original standard describes a communication layer based on SPI with additional HW lines for flow control and timing. This standard is being revised to support two popular serial interfaces: UART and USB.

 

IEEE 1451.3 *** defined a transducer-to-NCAP interface and TEDS for multi-drop transducers using the HPNA communication protocol.  It allows 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. Addition to the TEDS was defined for other sensor types as well.

 

IEEE P1451.5 * defines a transducer-to-NCAP interface and TEDS for wireless transducers. Wireless standards such as 802.11 (WiFi), 802.15.1 (Bluetooth), 802.15.4 (ZigBee) are being considered as some of the physical interfaces.

 

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

HPNA=Home Phoneline Networking Alliance