The safety grating can be classified as presence detection device. Other common presence detection devices include pressure sensitive safety pads and laser scanners (commonly used in remote control vehicles for industrial applications). Most industrial safety relays are mainly used in workstations with robots.

The safety grating is composed of a group of transmitters and receivers. The transmitter will transmit a group of infrared beams, while the receiver will include many optical sensors. If the object is between the transmitter and the receiver, and the receiver cannot receive a complete signal, it will send a stop signal to the monitoring equipment.

The light beam sent by the safety grating transmitter is sequential and sent at a specific frequency. The detector can only receive specific pulse waves of specific frequency sent by the transmitter, so it can avoid being affected by other infrared light sources and improve its applicability in the safety system.

Generally, the safety grating will be connected to the safety relay. If an object is detected, it will automatically remove the power source that may cause harm. The safety relay can also temporarily suspend the function of the safety grating, allowing objects to pass through the safety grating without generating protection signals, which is applicable to some semi-automatic programs.