Light barriers
What is a light barrier?
A light barrier is essentially a system that detects when a light beam is interrupted. In this case, the light barrier automatically emits a signal, such as an alarm. Therefore, light barriers are found in industry as well as in private homes. The most common designs are one-way and reflective light barriers. There are also, for example, light grids and reflective light sensors. They operate on different principles but also share some similarities. Below you will find the most important things you should know about light barriers.
What is a light barrier used for?
This happens without any physical contact. A light barrier can, for example, be installed on self-closing doors. When the door opens or closes, the sensor can detect obstacles. If it is integrated into an alarm system, the light barrier detects unauthorized intruders and typically triggers an alarm.
Typical uses include:
- Property and external surveillance
- Alarm systems
- Interior monitoring
- Locking systems
- Door barriers
- Automation technology
- Mechanical and plant engineering
What is a disposable light barrier?
Light barriers typically consist of a light source that acts as a transmitter. There is a sensor at the other end of the beam. Its task is to receive the radiation. If an object now enters the beam, the signal from this entering object is interrupted at a certain point. The receiver voltage decreases. Now the sensor immediately triggers an electrical signal.
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What is a reflection light barrier?
In contrast, there are at one Reflective photocell Transmitter and receiver in the same housing. There is a reflector at the opposite end of the beam. Here, too, the receiver captures the light emitted by the transmitter. However, this happens here after it was thrown back to the starting point by the reflector.
What is a light grid?
at a light grid several disposable light barriers are arranged parallel to each other. All transmitters are in one housing. The receivers are also combined in the same housing. Because the transmitter and receiver are combined in two housings, the installation effort is significantly lower. Light grids are primarily used in the context of safety systems, because even large areas and areas can be reliably monitored with light grids.
What makes a good light barrier?
Anyone who buys a light barrier should take a conscientious look at their quality features in advance. Above all, this includes the reliable recognition of objects. This must be done independently of the surface quality, color and shape of the object in question. In the best case, the light barrier even manages to precisely recognize almost transparent objects or even reflective objects.
Which light uses a light barrier?
As a light source come in light barriers For example, LEDs with a wavelength of 660 nanometers are used. These diodes emit a red light that can be visible to the human eye. Infrared LEDs, on the other hand, are in the infrared range of 880 to 940 nanometers. This infrared light has the significant advantage that it is not visible to the human eye. This is particularly advantageous for alarm systems, because possible intruders should not notice the system. Otherwise they could overcome them.
Who is allowed to check the function of the light barrier?
If a photocell is checked, this is done by checking the transmitter and receiver by measuring the voltage in volts. This functionality test should only be carried out by experienced specialist personnel.