What is the difference between water dewpoint and hydrocarbon dewpoint in natural gas?

Water dewpoint is defined as the temperature to which the gas must be cooled in order for water condensation to begin forming (i.e. the gas has become fully saturated with water vapor).   Hydrocarbon dewpoint is the temperature to which the gas must be cooled in order for hydrocarbons to begin to condense (i.e. the gas has become fully saturated with hydrocarbon vapor).  The Vaisala HUMICAP® Dewpoint and Temperature Transmitter HMT360N is designed to measure the water dewpoint of natural gas.