Abstract: A conveyor or drive chain wear monitor includes two sensors spaced apart from one another a predetermined distance which is less than the distance between the two selected measuring points on a chain. Two timers are provided, one of which is a chain speed timer and the other of which is the chain wear timer. The two timers are both controlled by the spaced sensors. The problem of sensor beams being broken by irrelevant beam breaking obstacles located between the successive spaced measuring points is solved by providing an ignore obstacle software routine in the wear monitor computer. The ignore obstacle software routine allows a user to program the monitor to ignore any number of irrelevant obstacles which might occur between two spaced measuring points on a chain.