Patent attributes
A compact CMM touch probe may include internal digital processing, a regulated power circuit, a trigger signal generating circuit, an interface connector limited to two electrical connections, and a differential signal configuration that inputs and outputs differential digital communication signals (including touch trigger signals) through the two connections, superimposed on a CMM supply voltage connected to them from the CMM. A specialized supply isolation circuit is configured in combination with various probe components and operating parameters, to couple the regulated power supply circuit to the CMM supply voltage at the two connections, while isolating it from loading the differential digital signals, which are AC coupled to the two connections. The differential digital signals may normally comprise touch trigger signals, and intermittent control and data signals, during separate respective time periods. In various embodiments, at least a majority of the differential digital signals are formatted using a DC-balanced encoding scheme.
