Smart sensors improve performance of data-acquisition and control systems

The Transducer Electronic Data Sheet (TEDS), also known as "smart sensor" technology, is shifting the balance of system intelligence from the operator and instrumentation to the sensors, creating systems with both increased ease of use and enhanced capabilities. Unlike standard systems that require extensive sensor knowledge for configuration, systems incorporating the IEEE 1451(TEDS) standard benefit from all necessary sensor information being preloaded and built in to the measurement devices.

Reducing system setup time
This intrinsic sensor knowledge helps system builders drastically reduce setup time while adding enhanced flexibility through a "user defined" area of the TEDS chip. This area can store data for any purpose deemed necessary by the designer, such as identification numbers, the name of the operator who last calibrated the sensor, or even location in a test structure. For example, it is now possible to program into the TEDS sensor the exact location for each gage on an aircraft wing containing thousands of strain gages. Since each sensor is then known by its internally programmed location, there is no longer the need to match channel numbers with transducer numbers or to have someone walking on the wing tapping each sensor to test the channel. Thankfully, reading wax-pen wire labels and "sensor thumping" are becoming a thing of the past with smart sensor technology.

Increased documentation simplicity
Since all sensor information is stored electronically on the smart sensors, the simplicity of TEDS extends beyond setup to documentation. There is no longer a need for entire hard-copy chapters recording sensor characteristics or collections of data sheets for field deployment. Similarly, with the growing adoption of TEDS technology, searching a manufacturer's Web site for data sheets for a sensor you just pulled out of an old box is becoming obsolete. Additionally, the electronic TEDS format is a robust solution for backing up data should a programming error wipe out on-board information.

More accuracy, easier calibration
Smart sensor technology also facilitates a more highly automated calibration process on a per-sensor basis. Engineers can preprogram a TEDS chip to compensate for known system errors that result from scale, offset, temperature drift or gain and that would affect accuracy. Calibration software simply scans through a list of sensors and finishes the process by uploading the final output equation to the TEDS chip located on the calibrated sensor. With the elimination of calibration sheet creation, storage and tracking, operators can afford to calibrate more sensors more often, resulting in a more consistent, more accurate test or control system. Mistakes such as improper data sheet transcription or decimal point misplacement do not exist in a properly implemented TEDS system.

Enhanced instrumentation flexibility
Adding support of the 1451 standard to a system also greatly enhances instrumentation flexibility, since systems now can be designed to work with multiple sensor types, with absolutely no reconfiguration needed. For example, simple displays that previously measured only strain gage now can measure any compatible TEDS sensor by automatically reading the embedded sensor information and configuring the hardware driver for the new measurement. A single display can now measure strain, force, load, torque or pressure without the operator having to touch a single data sheet.

One of the main benefits of TEDS technology is that at no time can all use cases be quantified. The flexibility and simplicity of this standard will ensure that new applications will continue to appear as the technology is further adopted by the sensor world.

About the author

Brett Burger is the product-marketing engineer for signal conditioning at National Instruments., Austin, TX.