1.2.2 Error of single measurement
(1)In general,the instrument error indicated in the specification of the instrument can be viewed as the error of a single measurement.
(2)If the instrument error is not given,for an instrument with an estimation of reading,half of the minimum scale of the instrument as the error ε of a single measurement,and
of that also functions as the standard deviation S of the measurement.(https://www.daowen.com)
(3)For some instruments without an estimation of reading,
of the smallest scale as the error of a single measurement is available.