SURFACE MEASUREMENT PROBE

摘要

Apparatus and method of determining drift for a surface measurement probe. The surface measurement probe has a housing, a surface contacting stylus, a vibration generator which causes vibration of the stylus, a sensing device for determining a parameter related to change in vibration of the stylus, and a comparator for determining the relationship of the parameter with a threshold. Readings of the parameter are taken when the stylus is not in contact with a surface and averaged over a time t, which is significantly larger than the transition time when touching a surface. The average of the readings of the parameter is compared to a reference parameter. The comparison is used to determine whether there has been significant drift of the parameters. Thus drift due to temperature change is corrected.