Light curtains are categorized into two uses, a safety light curtain and a measurement light curtain. Safety light curtains are mainly used for industrial safety and protection, while measurement light curtains are suitable for checking whether products comply with regulations.

Measuring Principle of Light Curtains

A photoelectric sensor is an electronic device that senses changes in the intensity of the light it receives, and consists of an optical system, an amplifier, and a switching output device. All photoelectric sensors use modulated light to exclude possible influences from surrounding light sources. When operating, the photoelectric sensor emits light, and when the object to be detected passes by, depending on the detection mode, the object either absorbs the light or reflects the light back to the photoelectric sensor's light-receiver, which results in a change in the intensity of the light received by the light-receiver, and the value of the change triggers a switching signal output to realize the detection function.

Measurement light curtains are special photoelectric sensors that, like ordinary counter-reflective photoelectric sensors, consist of two parts, an emitter and a transceiver, which are separated from each other and placed in relation to each other, but have a larger, longer, tubular form factor. Measurement of the light curtain emitter generated by the detection of light is not as ordinary sensors as only a beam, but along the length of the direction of the fixed-pitch generation of light arrays, the formation of a "light curtain", a scanning way, with the controller and its software, to achieve the monitoring and measurement of the external dimensions of the object's function.

Light curtain measurement system to work properly need to be equipped with a controller, the controller is programmed using software, can provide a variety of scanning modes and detection and analysis modes, and can be communicated with the PLC or computer through the serial interface, to transfer the control or scanning results, in addition to access to the trigger signal to control the scanning process.