The 3 R’s of analog position sensor-based mechanical measurements (.PDF Download)
Those of us old enough to remember the “good old days” recall that grade school focused on learning the 3 R’s: reading, ‘riting, and ‘rithametic. In the world of sensors, there are also 3 R’s: Repeatability, resolution, and response. As important as these sensor parameters are, there is often confusion in the mind of users about exactly what they mean and in what ways they tend to interact with each other. This article attempts to explain these 3 R’s for position sensors and to dispel any confusion that exists.
Definitions
Repeatability is a measure of the variation between outputs of a sensor-based measuring system for repeated trials of an identical mechanical input in a constant environment. Common practice is to use at least three repeated inputs, but five or more identical inputs are considered to be an even better sample for determining this parameter.