How the safety light curtain works
For semi-automatic equipment, safety light curtains are often used, and safety light curtains are only used on semi-automatic equipment. The main reason is that semi-automatic equipment requires human intervention.
Some people will ask, don't you need to be fully automatic? Fully automatic machines can also be accessed by people. For example, people supply materials in batches. Even if they have batch materials, but people cannot go to the moving parts of the mechanism, it is safe. The people on semi-automatic equipment are safe. It is necessary to go to the part of the sports organization frequently, so it is not very safe, so the intervention of the safety light curtain is necessary.
There are many optical axes on the safety light curtain. When every bald head comes, the distance between him and another light family is different. The light curtain is also classified by this. If we are worried about our fingers reaching in and hitting Nantong Chaohui uses two bald heads, the distance is about 5 mm, this kind of light curtain is usually not too high, whoever dares to use the range will not be too big.
The number of optical axes per unit length of the light curtain determines the price of the light curtain. Each bald head is actually equivalent to a commonly used optical fiber sensor. Then, how much does it cost for an optical fiber sensor? , Let’s take the length of 200 to calculate, there are 40 optical axes on it, and even if an optical axis is 100 yuan, the price will be 4000 yuan.
Generally speaking, the light curtain is divided into the transmitting end and the receiving end, and they appear in pairs. Another parameter is the distance between the receiving end and the transmitting end. This distance is strictly the same as the optical fiber and can be set. Yes, it can be set on the fiber amplifier. The sensing area is the area between the transmitter and the receiver.
The other is the output mode of the safety light curtain. This output mode has two output modes, NPN and PNP. Most of our automatic machines usually use NPN. This depends on whether the PLC is intended to form a source. The type is still missing. In principle, it can be connected to any type. It is just that our other sensors are all unified. For example, if you say that other sensors have selected PNP, then this safety light curtain can also be selected as PNP. of.
The working principle of the safety light curtain is as follows. The signal that emits light at one end is similar to a light bulb and illuminates the opposite side. When the receiving end receives the irradiated light, it gives a signal that no object enters the sensing area of the light curtain at this time. Inside, when some of the optical axis between the receiving end and the transmitting end is blocked, the receiving end does not get light, then the light curtain hits the atmosphere to determine that there is an object in the middle, and there is an object between the light curtain indicating a safety hazard, then the master circuit Immediately report to the police in an integrated manner.
It is worth noting that some people can't distinguish between the light curtain and the grating ruler. The grating ruler is a device for measuring length and measuring position, while the light curtain type safety sensor switch.