Repeatability

Repeatability (F_Rep) is an important quality term for electrical measurement technology. It expresses how far the results of consecutive averaged measurements of the same measurement object (voltage, current, etc.) deviate at maximum from a value which has been established as the measured value under constant (i.e. identical) conditions. In principle, repeatability can therefore be understood as the remaining noise over a fixed (longer) period of time.

At Beckhoff, repeatability is:

• defined as +/- value from the device measured value
• over a period of 24 h and
• after averaging over (usually) 2 seconds
• and determined at an ambient temperature of 23°C

Note: An empirical investigation of repeatability with self-selected setting parameters (e.g. average values over a specific period of time) on the installed overall setup (source, lines, external influences) can be helpful in estimating the stability of the measuring results

As an example, here is the measurement of an analog channel, with averaged measured values over 19 hours: