Both curtains and safety barriers are to protect against human intrusion into the danger zone.If a person (or some other object) cuts even one beam, a signal is sent to the machine control system.The light curtain is also a protective barrier. These opto electronic protective devices should be constructed in such a way that their operation is not affected by electrical interference or other light sources.It is accepted that light barriers emit several light rays, while light curtains - a dozen or even several dozen. Light barriers are usually used to monitor hazardous areas near machines.Their use is intended to warn about entering a hazardous area and turning off the machine.Two parallel light rays are often sufficient to detect a human figure. In turn, light curtains are most often used to monitor the zone directly at the machine and are designed to detect when the controlled zone is exceeded even in a small area, e.g. detection of a hand or even the operator's finger.
Construction and parameters of light barriers
As already mentioned earlier, barriers consist of two main elements: transmitter and receiver. The transmitter sends parallel beams of infrared radiation; these beams are modulated by a certain frequency. The receiver only Safety Barriers accepts beams with beam parameters sent from the transmitter - this is a prerequisite for other light sources not to interfere with the barrier. Of course, exact alignment of the transmitter and receiver is required.
Blanking -
A function that allows switching off the desired ray beams.This is often necessary if parts of the machine (or other devices), fixed or mobile, are to be in the curtain detection one.
Response time -
The period of time that elapses from the moment the ray (beam of rays) is interrupted until the machine stops;it is usually about 2 ms.
Safety class -
type 1: short range Safety Barriers components, where the highest level of safety is required;type 2: components with lower requirements, where the frequency of exposure to hazard is low.
Number of rays -
Safety Barriers and curtains are offered in single-beam or multi-beam versions. Single beam (single beam) barriers are used to detect large objects and are usually placed further away from the machine. In contrast, multi-beam curtains can detect small objects or objects of different sizes.