A conveyor system has a plurality of sensors coupled to a computer system, the computer system being programmed to check a number of safety functions greater than the number of sensors. A method of controlling the safety function of the conveyor comprises providing signals from a plurality of sensors disposed in relation to the conveyor to a computer system; operating the conveyor in a learn mode; during operation in the learn mode determining in the computer system the relationship between the sensor output signals and pre-stored logic in the computer system which describes the physical geometry of the possible conveyor types and permissible operating characteristics thereof and determining the relationship between the sensor output signals to establish the safety integrity of the sensors, and storing sensor signal patterns as a reference pattern; and subsequently operating the conveyor in a run mode in which safety functions are monitored; and during the run mode comparing in the computer system the pattern of sensor signals with the reference pattern and with the pre-stored logic so as to establish the safety integrity of the sensors, of the computer system and of the operation of the conveyor.