Automating Data Acquisition on a Mechanical Equal Arm Balance Used in Large Mass Calibrations
Kevin L. Chesnutwood
This paper focuses on efforts by the Mass and Force Group at the National Institute of Standards and Technology (NIST) to enhance the data taking operations of an approximately 40 year-old mechanical two-pan equal-arm balance used for high-precision mass comparisons in the range from approximately 50 kg to 1134 kg (110 lb to 2500 lb). The repeatability and sensitivity of this manually operated balance (called the Russell balance) has not been found to be matched or surpassed by current digital comparator technology. Therefore, the balance remains a core component of the NIST large mass laboratory. In order to enhance the data taking procedure and reduce the potential uncertainties inherent with human involvement in the data collection process, an automated system was designed and installed to obtain the turning points of the balance taken during calibration that ultimately are used to convert scale units to SI mass units. This paper discusses the advantages of the improved system, the challenges that had to be overcome, and the design, operation, and verification of the automated system.
Automating Data Acquisition on a Mechanical Equal Arm Balance Used in Large Mass Calibrations, NCSL International Measure, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=903499
(Accessed June 4, 2023)