Abstract: A method of communicating information to a measurement probe mounted on a coordinate positioning machine includes encoding the information as one or more of a plurality of characteristic movements of the probe, controlling the machine to impart the movement(s) to the probe, detecting the movement(s) at the probe, and decoding the information at the probe from the detected movement(s). A measurement probe for use in such a method is mountable to the machine and includes at least one movement sensor for sensing movement imparted to the measurement probe by the machine, and a controller for determining whether the sensed movement includes one or more of the plurality of characteristic movements of the probe and for performing an operation at or controlling operation of the probe in dependence on the determination.

Abstract: A measurement probe is described that includes a probe body, a stylus that is deflectable relative to the probe body, and a plurality of sensor elements for generating a sensor signal indicative of stylus deflection. An analyser is provided, optionally as part of a trigger unit, to analyse the sensor signals and issues a trigger signal to indicate the stylus has contacted an object. The analyser is arranged to combine a plurality of the sensor signals to generate a resultant deflection signal for comparison to a deflection threshold and is also arranged to detect oscillatory motion of the stylus by analysing at least one of the sensor signals. The analyser only issues a trigger signal when the resultant deflection signal crosses the deflection threshold and no oscillatory motion of the stylus is detected. The measurement probe may be used on a machine tool or other coordinate positioning apparatus.

Abstract: A measurement probe is described that includes a probe body, a stylus that is deflectable relative to the probe body, and a plurality of sensor elements for generating a sensor signal indicative of stylus deflection. An analyser is provided, optionally as part of a trigger unit, to analyse the sensor signals and issues a trigger signal to indicate the stylus has contacted an object. The analyser is arranged to combine a plurality of the sensor signals to generate a resultant deflection signal for comparison to a deflection threshold and is also arranged to detect oscillatory motion of the stylus by analysing at least one of the sensor signals. The analyser only issues a trigger signal when the resultant deflection signal crosses the deflection threshold and no oscillatory motion of the stylus is detected. The measurement probe may be used on a machine tool or other coordinate positioning apparatus.

Abstract: A dimensional measurement probe (10) is mounted in a machine tool (48), which reorientates the probe about at least one axis A. Strain gauges (34) sense when a stylus (20) of the probe contacts a workpiece (50), to produce a trigger signal. False trigger signals may be produced when the probe is reorientated. To overcome this, the reorientation is detected by monitoring changes in the fluctuations of the strain gauge outputs, caused by vibrations of the stylus.

Abstract: A dimensional measurement probe (10) is mounted in a machine tool (48), which reorientates the probe about at least one axis A. Strain gauges (34) sense when a stylus (20) of the probe contacts a workpiece (50), to produce a trigger signal. False trigger signals may be produced when the probe is reorientated. To overcome this, the reorientation is detected by monitoring changes in the fluctuations of the strain gauge outputs, caused by vibrations of the stylus.