An instrument gives the same indication each time it measures a variable under identical conditions. This defines:

The definition provided in the question refers to the concept of repeatability, which is a critical aspect of measurements in control systems. Repeatability indicates the ability of an instrument to produce the same results when measuring the same variable under consistent conditions multiple times. This characteristic is essential in ensuring the reliability and credibility of measurements in various applications.

Repeatability takes into account the instrument's performance in a controlled environment, where external factors remain unchanged. It reflects both the precision and consistency of the instrument's measurements, making it a vital parameter for technicians and engineers in evaluating the effectiveness of their measuring devices.

By focusing on the consistency of measurement results under identical conditions, repeatability assesses how well an instrument can maintain performance, which is crucial in processes that require precise control and monitoring. Thus, in scenarios where multiple readings yield the same value, this underscores the instrument's repeatability.