US Patent 12085413 Measurement apparatus and method

A measurement apparatus for mounting within an enclosure of a machine is described. The apparatus includes a measurement device and a protection means for protecting the measurement device from contaminants present within the machine enclosure. The protection means is switchable between at least a first mode that protects the measurement device from contaminants and a second mode that provides less protection of the measurement device from contaminants than the first mode. A contaminant sensor is used for sensing contamination within the machine enclosure and thereby determining when the protection means can adopt the second mode. A corresponding method is also described.