Measuring light grids control a defined monitoring area with several invisible, infrared light beams. The light grid systems consist of a transmitter (TX) and a receiver (RX) in slim anodized aluminium profile and an external controller. They operate on the principle of single beam evaluation whereby the signal strength of each individual beam is detected by the external controller. Thereby, complex measurement tasks can be performed and the controller activates corresponding outputs as well as digital data transfer.