Measurement probe systems for co-ordinate positioning apparatus

摘要

A measurement probe (2;90;100;150;200), such as a touch trigger measurement probe (2;90;100;150;200), is described that comprises a measurement portion (6;158;254) for measuring an object and a data transfer portion (8;16;124) for receiving data from and/or transmitting data to an associated unit (18;94;118;126;152). The measurement device also comprises an authentication module (13;50;113;159) for verifying the authenticity of the associated unit. The authentication module may include a processor (12) for running a one-way hash algorithm. Authenticity may be established using a challenge and response authentication process.