ANALYSIS OF A PROJECT THE NATIONAL TRACEABILITY CHAIN FOR INSTRUMENTS MEASURING MASS AND VOLUME OF LIQUID IN A FLOW

The article provides a comparative analysis of the canceled, current and draft new version of the state verification scheme for measuring the mass and volume of liquid in the flow. The prerequisites and reasons for making changes are considered, as well as the estimated consequences of the changes made for the metrological services using standards and instruments for measuring the mass and volume of liquid in the flow.

State verification scheme for means of measuring DC and AC electrical resistance

The need to develop a new state verification scheme (SVS) is caused by the emergence of high-precision bridges, resistance measures and boxes with a low temperature coefficient (0,02–0,5) ppm/К, highly stable transient measures, electronic resistance calibrators, and high frequency resistance measures. Recommendations how to assign the status of a working standard to measures, R-meters and measuring shunts with accuracy from 0,005 % to 0,500 %, sufficient for verification of measuring instruments, are given. SVS consists of two parts: part 1 covers electrical resistance measures, boxes and R-meters, part 2 – to measuring shunts and shunt resistance meters. Part 2 was introduced to the SVS for the first time. The revised indicators of accuracy for working standards of all levels are considered, conditions for the investigation of measuring instruments for assigning the status of a working standard, criteria for assessing metrological characteristics are given.