The National Institute of Standards and Technology (NIST) has six dead-weight machines (DWMs), used for force calibrations up to 4.4 meganewtons (MN), which were all placed in service ca. 1965. More than 20 years later, five of these machines were automated. They now automatically apply programmed force values to the strain-gauge load cell and record the output using a high-precision digital voltmeter, all controlled by a PC-XT class computer. Subsequently, environmental chambers have been added to three machines to perform automatically the type evaluation testing of load cells used in scales in commerce.
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