What causes the measurement error in the IncOder’s output?

As with any measuring device, there will always a difference, no matter how small, between the device’s measurement and reality. This is called the measurement error and the maximum error is quantified by the device’s accuracy. An IncOder’s measurement error is made up from a number of smaller errors caused by imperfections in the etched winding patterns; non-planarity of the sensing surfaces; errors caused by installation tolerances etc.