Safety gratings are also photoelectric safety protection devices (also known as safety protectors, punch protectors, infrared safety protection devices, etc.). Generally speaking, safety gratings exist in pairs and are divided into transmitter and receiver.

Safety grating is an optoelectronic device that avoids personnel from approaching mobile machinery, which can avoid casualties. Such mobile machinery includes punches, winding machines, palletizers, elevators, etc. Safety gratings can be used to replace traditional mechanical barriers or other mechanical protection, and can also increase the maintainability of equipment. With the safety light grid, it can also increase the operability and efficiency of mechanical equipment (like some semi-automatic equipment). Safety light barriers can be classified as presence detection devices, other common presence detection devices are pressure sensitive safety mats and laser scanners (often used in remote control vehicles in industrial applications). The main application for most industrial safety relays is in workstations with robots.

The safety grating is composed of a set of transmitters and receivers. The transmitter will transmit a set of infrared beams, and the receiver will include many light sensors. If the object is between the transmitter and the receiver, the receiver will receive it. If the signal is not complete, a stop signal will be sent to the monitored equipment.

The light beam sent by the safety light grid transmitter is sequential and sent out at a specific frequency. The detector can only receive the specific pulse wave of the specific frequency sent by the transmitter, so it can avoid the influence of other infrared light sources and improve the applicability in the security system.