Proposed Changes to the Current IEEE 1451 Overall Architecture

1. Proposed Changes to the Current IEEE 1451 Overall Architecture Robert N. Johnson Telemonitor, Inc. robertj@telemonitor.com September 24, 2002 Sensors Expo, Boston

2. Outline • Review goals of IEEE 1451 • Background • Situation • What should we standardize? • Proposed “dot zero” standard • Expected results • Next Steps Sensors Expo, Boston

3. 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. Sensors Expo, Boston

4. First the Earth cooled... • 1994--First “Smart Sensor Interface Standards Workshop” held at NIST resulting in study group for standard • 1995--Study group forms two working groups: P1451.1 for the network processor model and P1451.2 for the transducer to microprocessor interface • 1997--IEEE 1451.2-1997 is approved. P1451.3 and P1451.4 working groups agree to maintain major IEEE 1451 family traits • 2001--IEEE P1451.5 study group starts work on a standard for wireless sensor • 2002--Proposals made to coordinate the TEDS and operational models of the family of IEEE P1451 standards to improve compatibility and reduce duplication of effort Sensors Expo, Boston

5. 1997 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 1451.2 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 Sensors Expo, Boston

6. 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 1451.1 and 1451.2 are up for revision and renewal, and the proposed standards P1451.3, P1451.4, and P1451.5 are not yet approved. Sensors Expo, Boston

7. 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 Sensors Expo, Boston

8. 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 Sensors Expo, Boston

9. Calibration TEDS Channel ID TEDS Calibration ID TEDS Meta-TEDS (mandatory) Channel TEDS (mandatory) Industry Extension TEDS Industry Extension TEDS Industry Extension TEDS Meta-ID TEDS End Users’ Application specific TEDS It’s the TEDS…! Application specific Machine readable Human readable Future extensions Sensors Expo, Boston

10. Partition the TEDS New Physical Interface Meta TEDS Move physical interface related fields New Meta TEDS New Channel TEDS New Physical Interface Channel TEDS Meta-ID TEDS Other TEDS blocks can remain the same. Supports use of different physical layers. Channel-ID TEDS ... Sensors Expo, Boston

11. Calibration TEDS Calibration ID TEDS Channel ID TEDS Meta-TEDS (mandatory) Channel TEDS (mandatory) Industry Extension TEDS Industry Extension TEDS Industry Extension TEDS Meta-ID TEDS End Users’ Application specific TEDS Physical layer Meta-TEDS (Dot-X specific) Physical layer Channel-TEDS (Dot-X specific) Proposed IEEE P1451.0 TEDS Architecture Application specific Machine readable Human readable Future extensions Everything not “Dot-X specific” is defined in IEEE P1451.0 Sensors Expo, Boston

12. What About IEEE P1451.4? • The compact TEDS proposed for IEEE P1451.4 cannot include a complete IEEE P1451.0 TEDS, although a template file can provide most of the content • Also, since the data for a P1451.4 device is analog, a lot of the TEDS content is not applicable • BUT, the module that the P1451.4 device connects to can provide the translation to the full P1451.0 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 P1451.4 or another flavor Sensors Expo, Boston

13. Results of IEEE P1451.0 • 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 P1451.0 standardizes the message, not the medium Sensors Expo, Boston

14. What Next? • Form an IEEE P1451.0 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 Sensors Expo, Boston

15. Questions/Comments? Sensors Expo, Boston