4.3.3.1 General descriptionThe ferrule under test is mounted by means of a stable fixture positioned on a moving stage.The ferrule axis shall be positioned perpendicular to the stage moving direction. By means ofan optical system (microscope fitted with a precision video camera) or a mechanical system(inductive or capacitive sensor) the position of one of the two edges of the ferrule cylinder isobtained and recorded as x1. Then the position of the opposing edge of the ferrule is obtainedby moving the stage across the ferrule diameter and recorded as x2. The ferrule diameter isthe difference between the two positions of the moving stage (x2-x1).4.3.3.2 Inspection conditiona)‘The accuracy of the mechanical parts, the mounting fixture and the movement of thesystem shall be sufficient to guarantee the required accuracy and repeatability.b) The optical viewing system shall incorporate an x-y marker positioned at the centre of theimage.c) The optical and the video systems shall have the required optical quality, accuracy, andlinearity to achieve the required measuring resolution and accuracy.d) It shall be possible to calibrate the measuring set-up by means of a reference gauge ofdiameter comparable to the diameter of the ferrule under test.e) It shall be ensured that the environmental conditions during the test are controlled andstable, and are the same during both the calibration of the equipment and the measurementof the ferrule.