| 摘要 |
The probe has a piezo-electric sensor (22A) for determining initial contact of a stylus (16) with a workpiece (4). It also has a kinematic support (18) made up of confronting electrical contacts (19,20) which are connected to indicate displacement of the stylus from a rest position and correct reseating on the kinematic support. The sensor (22A) and the electrical contacts (19, 20) are connected to an electrical circuit (24) within the probe. The circuit (24) has only two terminals connecting it to an external interface (9), which both receives the signals from and supplies power to the sensor (22A) and the contacts (19,20). This enables the receipt of a signal from the contacts (19,20) to provide a fail-safe backup to the signal from the sensor (22A) and to indicate correct reseating of the probe, while maintaining the interface (9) compatible with prior art probes having only one workpiece-engagement sensing arrangement with two terminals. |
