A system for monitoring production of uniform strands, such as medical sutures, utilizes a measurement head through which the strand passes. The measurement head includes a plurality of light beams illuminating a corresponding number of sensors. The light beams all illuminate the same section of the strand as it travels through the measurement head. Passage of a fault through the light beams produces a fault signal, which is used by the production system to excise and discard the strand section including the fault. Synchronization and summing of the plurality of fault signals increases the sensitivity and accuracy of the system.