Abstract: Disclosed is a sensor shield for use in a multi-shelf merchandise display unit including a plurality of sensors mounted on a wall of the unit and opposite a source of illumination, in which each sensor corresponds to a single shelf and in which the shelves are at least semi-porous to the illumination. The shield comprises i) a plate having a length that is sufficient substantially to reduce or prevent incident illumination from the shelf above reaching the sensor; and ii) means to attach the plate to casing of or around the sensor or the wall of the unit. The plate is opaque to the illumination detected by the sensor. Also disclosed is a method to reduce the interference of light in a multi-shelf merchandise display unit from shelves above a shelf on which stock levels are being measured and a method for monitoring stock levels in a retail display cabinet by measuring light entering the retail display cabinet.

Abstract: Described is a method for maintaining a retail display or vending unit. The method includes obtaining and storing data from sensors located in or on the unit in a control system including data communication means, wherein the data is sent to and accessed by remote telecommunication means via the data communication means, and wherein operation of the unit is changed based on the data.

Abstract: Disclosed is a sensor shield for use in a multi-shelf merchandise display unit including a plurality of sensors mounted on a wall of the unit and opposite a source of illumination, in which each sensor corresponds to a single shelf and in which the shelves are at least semi-porous to the illumination. The shield comprises i) a plate having a length that is sufficient substantially to reduce or prevent incident illumination from the shelf above reaching the sensor; and ii) means to attach the plate to casing of or around the sensor or the wall of the unit. The plate is opaque to the illumination detected by the sensor. Also disclosed is a method to reduce the interference of light in a multi-shelf merchandise display unit from shelves above a shelf on which stock levels are being measured and a method for monitoring stock levels in a retail display cabinet by measuring light entering the retail display cabinet.