1. MeasurementPrecision and Common Issues and Solutions Mark Skiba Vektrex

2. The “Common” precision issue AF requires precision of measurements to be expressed in their TestResults –instruments must be 3x more precise than measurements No standard way of expressing precision/resolution of measurements in TestResults using current common Datum types DatumDouble has maximal precision with trailing 0’s truncated

3. “Implied Precision” Solution Use existing Datum double Format number using “Implied Precision” –Precision is determined by number of decimal places in the to the right of the ones place in the string e.g. 4 volts DC with milivolt precision would be

4. “Explicit Precision” Solution Extend Datum types elements –Resolution/error limits/confidence as explicit elements e.g. 4 volts DC with milivolt precision might be

5. Comparative Advantages Implied Precision Can use the current trial use schemas Explicit Precision Better follows XML standards and style guide Easier to support in tools More likely to get correctly supported Provides more information such as fractional decimal resolution, uncertaintly, range etc.

6. Hybrid Transitional Solution Trial use: Use implied precision Datum double in XML files Map internally to explicit extended Datum object type in tools Future use: Use explicit Datum extension when it becomes available

7. Recommendations Use “implied precision” in datum double measurements with the current trial use standard Add an “explicit resolution/uncertainty/confidence/errorLimi t/range” sub elements to the abstract DatumType to the next revision of the common standard

8. Element “Quantity” Requirements Child of DatumType Sub elements: –Resolution (xs:double) –Error Limits (c:Limit) –Range (c:Limit) –Confidence (xs:double in percentage)