Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston1 Proposed Changes to the Current IEEE 1451 Overall Architecture Robert N. Johnson Telemonitor, Inc. September 24, 2002

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston2 Outline  Review goals of IEEE 1451  Background  Situation  What should we standardize?  Proposed “dot zero” standard  Expected results  Next Steps

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston3 Main goals for IEEE 1451  Develop network independent and vendor independent transducer interfaces.  Allow transducers to be replaced and/or moved with minimum effort.  Eliminate error prone, manual system configuration steps.  Support a general transducer data, control, timing, configuration and calibration model.  Develop Transducer Electronic Data Sheets that remain together with the transducer during normal operation.

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston4 First the Earth cooled...  First “Smart Sensor Interface Standards Workshop” held at NIST resulting in study group for standard  Study group forms two working groups: P for the network processor model and P for the transducer to microprocessor interface  IEEE is approved. P and P working groups agree to maintain major IEEE 1451 family traits  IEEE P study group starts work on a standard for wireless sensor  Proposals made to coordinate the TEDS and operational models of the family of IEEE P1451 standards to improve compatibility and reduce duplication of effort

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston Architecture Guidelines  Interfaces are defined, not modules  Modules may support multiple interfaces  Higher-level standards must be maintained  At that time this meant providing a way to generate a TEDS  Partitioning is invisible beyond the immediate interface  A module or network device should not have to know or care what interfaces are implemented past the immediate one  Hot swaps must be allowed and passed on  Each standard must support a way to simulate the “hot swap” of a transducer and force the network-side device to accept the updated TEDS

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston6 Present Situation  The IEEE 1451 family of standards has established several valuable basic principles of smart transducers, the most important of which is the TEDS  Different physical interfaces are needed by different applications, and more will be needed in the future.  Unless guidance and coordination is provided, we will duplicate efforts and end up with incompatible devices in the standards family.  Now is the time to address this issue; IEEE and are up for revision and renewal, and the proposed standards P1451.3, P1451.4, and P are not yet approved.

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston7 Core Values of the IEEE 1451 Family  Extensible Transducer Electronic Data Sheet (TEDS)  General calibration/correction model for transducers  Data models based on common standards such as IEEE floating point numbers  Physical units representation based on SI units  Control and operation models for different kinds of transducers  Flexible correction engine concept  All of the above must be common in order to have a basis for a common TEDS

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston8 Power of TEDS plus correction engine Multi-channel acceleration/tilt sensor: Hardware channels for temperature and acceleration Correction engine performs temperature compensation Virtual actuators for zero correction Virtual sensors for tilt (roll and pitch) Correction engine converts to angle Number order of channels is important

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston9 It’s the TEDS…! Industry Extension TEDS Meta-TEDS (mandatory) Industry Extension TEDS End Users’ Application specific TEDS Meta-ID TEDS Machine readableHuman readable Application specific Future extensions Channel TEDS (mandatory) Calibration TEDS Channel ID TEDS Calibration ID TEDS

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston10 Partition the TEDS New Meta TEDS New Channel TEDS Move physical interface related fields New Physical Interface Meta TEDS New Physical Interface Channel TEDS Meta-ID TEDS Channel-ID TEDS Other TEDS blocks can remain the same. Supports use of different physical layers....

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston11 Proposed IEEE P TEDS Architecture Industry Extension TEDS Meta-TEDS (mandatory) Industry Extension TEDS End Users’ Application specific TEDS Meta-ID TEDS Machine readableHuman readable Application specific Future extensions Channel TEDS (mandatory) Calibration TEDS Channel ID TEDS Calibration ID TEDS Physical layer Meta-TEDS (Dot-X specific) Physical layer Channel-TEDS (Dot-X specific) Everything not “Dot-X specific” is defined in IEEE P1451.0

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston12 What About IEEE P1451.4?  The compact TEDS proposed for IEEE P cannot include a complete IEEE P TEDS, although a template file can provide most of the content  Also, since the data for a P device is analog, a lot of the TEDS content is not applicable  BUT, the module that the P device connects to can provide the translation to the full P content in addition to the conversion between digital and analog  The important thing is that we coordinate such things as units, data representation, correction engine, etc. for true family compatibility  Properly done, other network-side devices need not know if the transducer is P or another flavor

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston13 Results of IEEE P  Reduction in duplication of effort  Commonality and compatibility cross the entire IEEE 1451 family of standards  Common network-side view of all devices  Ease of adding additional physical media when they are needed in the future  The proposed IEEE P standardizes the message, not the medium

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston14 What Next?  Form an IEEE P study group  Coordinate common elements with chairs of all the existing working groups  Review existing and proposed dot-x standards for impact  Submit a Project Authorization Request to IEEE and form a working group  Write a draft standard  We need to act quickly and your input and participation can help

Smart Transducer Interface Standard - IEEE 1451 September 24, 2002Sensors Expo, Boston15 Questions/Comments?