Working principle of safety grating: general grating generally adopts DC12-24V safety voltage, and the power supply and control line are connected according to protection requirements; The safety grating illuminator transmits infrared light to the light receiver to form an infrared protective light curtain. When no object passes through the grating protective light curtain area, the grating signal can be received normally, the green indicator light is normally on, the fault indicator light is off, and the equipment is normally started. When an object (greater than the protection accuracy) passes through the protection area, the light is in a blocked state, and the grating will transmit this signal to the PLC or alarm. After receiving the signal, the fault indicator red light will turn on, and the equipment will stop running or give a safety alarm, so as to achieve the purpose of safety protection.