NOTE: As the analogue outputs from SP25M are non-linear and non-orthogonal, a third order polymer non-linear calibration method should always be used for optimum accuracy.
At the nominal free stylus position the probe outputs will not be zero. These zero offsets are determined and saved as part of the non-linear calibration.
For maximum probe performance in scanning mode, Renishaw recommends that the SP25M is qualified (calibrated) using a third order, polynominal, non-linear calibration method using two different deflections such as 0.2 mm and 0.5 mm. It is very important that during scanning operation the CMM controller maintains a deflection that is less than the higher of these qualification deflections.