Exploration of a Data-Enhanced Calibration Certificate as Part of a Complete Measurement Information Infrastructure

Every calibration laboratory creates calibration certificates that report technical and operational information about a device. Frequently, calibration certificates are issued in Portable Document Format (PDF) with little concern over whether recipients can electronically extract and use the calibration data at their facility. Sometimes data is saved as an image within the PDF forcing the use of optical character recognition or manual transcription to extract any information. These practices effectively lock the data and make it difficult to extract automatically. Without accessible data, tasks involving multiple certificates, such as control charting or interval analysis, become impossible. A universal Measurement Information Infrastructure (MII) includes a calibration certificate in a standardized, open format that allows easy access to the data for analysis, yet can be presented in a traditional, readable form. This paper explores some proof-of-concept ideas under investigation at the Primary Standards Laboratory for such an enhanced calibration certificate. An open specification based on mature technology will ease the transition from existing information systems to new MII standards. This paper describes how to embed Extensible Markup Language (XML) data into a PDF certificate, extract the information for reuse, store calibration certificates in XML format, and extend and customize the certificate to satisfy all requirements in ISO/IEC 17025:2017(E).