The customer was UME (National Metrology Institute of Turkiye), a research and development institute operating under the umbrella of TUBITAK (The Scientific and Technological Research Council of Turkiye), located in Kocaeli, Turkiye. Their primary mission is to validate all measurements conducted within Turkiye and ensure their international comparability. UME continuously develops and refines measurement techniques to enhance the precision of industrial and commercial measurements. To fulfill this mission, they have established the National Metrology System, which contributes to improving the quality of Turkish products and strengthening Turkiye’s scientific and technological infrastructure. UME also develops and maintains Turkish Measurement Reference Standards and ensures their traceability to the International Measurement System.
They were in need of a calibrator capable of performing three simultaneous calibrations of 500 kg masses. This calibrator was also expected to verify masses ranging from 100 kg to 500 kg, in accordance with OIML R-111 standards.
There was no standard production system, either within UME or worldwide, capable of delivering such performance. A project was initiated using World Bank credit, and a nationwide search was conducted for a technologically capable company in Turkiye.
Due to its strong reputation at UME, the team was selected as the main contractor. The team partnered with a subcontractor to manufacture the mechanical section of the calibrator.
This project was significant because the calibrator would serve as a national reference for the calibration and correction of weights at sub-laboratories throughout the country.
The calibrator and its associated software had to perform three calibrations simultaneously. UME also required computer software capable of conducting fully automated calibration cycles. The system needed to carefully control the loading and positioning speeds of the masses to prevent sudden shocks or friction and ensure their protection. Noise and heat dispersion within the system also had to be minimized.
The first major challenge was the fragility of the standard masses. As national references, they required extremely careful handling. The top platform had to move slowly enough to protect the weights, yet fast enough to complete three calibrations efficiently.
The second and most critical challenge was positioning. The total weight of the top platform was calculated as 4.5 tons, 2 tons from four 500 kg masses and 2.5 tons from the platform itself. This entire structure had to be precisely positioned onto a high-precision scale with a margin of error no greater than ±500 microns. The platform had to start rotating and stop gradually at the correct position.
Performing three calibrations simultaneously required the development of a more sophisticated software architecture. The team worked in collaboration with UME to define the calibration and calculation methodology, which was then implemented into the software. An automation system was created to operate both the calibrator and the computer simultaneously. The software communicated with a high-precision scale to read and record the mass values. It also controlled all sensors and motors online through a Schneider PLC (Programmable Logic Controller) and motor controllers. A first-of-a-kind machine learning artificial intelligence (AI) module was implemented to handle platform positioning. If the system failed to reach the target position using one algorithm, it would automatically try alternative algorithms until the correct result was achieved. Over time, the AI learned the behavioral patterns of the calibrator and adjusted accordingly to maintain long-term stability. It also managed all measurement routines, detected calibration anomalies, performed automatic retries, and generated printed “National Calibration Certificates.” A full calibration sequence was completed in approximately 33 hours without any human interaction.
Industrial-grade components were used, including Schneider PLCs and IFM laser sensors, ensuring highly accurate system control. Laboratory humidity and temperature were continuously monitored and factored into calibration corrections.
From July 2002 to February 2003, it took eight months to complete the development of fully integrated software and firmware. The mechanical design also posed significant challenges, particularly due to the 2.5-ton top platform, which was machined from a single monoblock structure.
Since 2003, UME has used this calibrator to conduct all 100 kg, 200 kg, and 500 kg mass calibrations. One year after implementation, experts from the Hellenic Institute of Metrology (EIM/Greece) visited the site to observe the system in operation.
The project was completed with minimal profit, as it was considered a national mission and reference standard.
Results from international intercomparisons of 500 kg calibrators have been published online.
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