A pump set for use with a pump to deliver a supply of liquid to a patient. The feeding set has a conduit for the nutrient liquid and a safety interlock device associated with the conduit. The pumping apparatus has a pumping device and a control system for controlling operation of the pump. An electromagnetic radiation source is operatively connected to the control system of the pump for emitting an electromagnetic radiation signal in a direction for striking the safety interlock device of the feeding set. The safety interlock device is adapted to affect the direction of the electromagnetic radiation. An electromagnetic radiation detector is operatively connected to the control system for receiving the electromagnetic radiation signal when the direction is affected by the safety interlock device, and providing an indication to the control system that the feeding set conduit is properly positioned in the feeding pump.