A sensor signal is generated from a plurality of sensors located on a sensing roll, wherein each signal is generated when each sensor enters a first nip between the sensing roll and a rotating component during each rotation of the sensing roll. A rotating applicator rod forms forming a second nip with the sensing roll such that each sensor enters the second nip during each rotation of the sensing roll. A periodically occurring starting reference is generated associated with each rotation of the applicator rod and the signal generated by each sensor is received so that a particular one of the sensors which generated the signal is determined and one of a plurality of tracking segments is identified. The signal is stored to associate the sensor signal with the identified one tracking segment.