Prerequisite

• Access to the File > Source of uncertainty (MA033) menu.

Introduction

A source of uncertainty is a way of determining the range in which the actual value of calibration measurements lies, and is usually associated with a confidence level. Each source of uncertainty can directly influence measurement results and must be strictly controlled and documented.

Examples of sources of uncertainty

• Environmental: changes in temperature, relative humidity, air pressure.
• Instrumental: variations in the performance of measuring instruments, wear and tear of components.
• Methodological: variability in technician performance, inconsistent measurement procedures.

Practical example

When calibrating a pressure gauge, the technician records sources of uncertainty, such as variation in ambient temperature and relative humidity. These variables are entered into the system and associated with the standard calibration activity. At the end of the process, the system calculates the total uncertainty of the measurement, allowing the technician to adjust the frequency of future calibrations based on the results obtained.

This record is required when the type B uncertainty is enabled in the standard calibration activity.

Creating a source of uncertainty

1. Access the File > Source of uncertainty (MA033) menu.

2. Click on the toolbar button.

3. On the screen that will open, enter an ID # and a name for the source of uncertainty.

4. In the Distribution field, select the type of distribution to be performed to determine the range of the source of uncertainty:

• Normal: results of repeated measurements are shown distributed around the average.
• Rectangular: presents the same probability for all values within the limits, and zero outside of them.
• Triangular: presents the maximum probability for the average value and decreases linearly to zero within the limits, and zero outside of them.

5. Click on the button to save the record.

Conclusion

Once saved, the record will be ready to be associated in the Type B uncertainty tab of the calibration table in the standard activity. For that , the appropriate resource must be enabled on the calibration data screen.

Using sources of uncertainty is crucial to ensuring the precision and reliability of measurements, as well as optimizing the use of resources and improving the efficiency of calibration processes. This way, the organization can maintain high standards of quality and safety in its operations.