There are three top events in the world: the Olympics, the World Cup and the World Expo. The World Expo, which is known as the "Olympic" event of the world economy, science and technology, and culture, has consistently implemented the concept of "Science and Technology Expo, Low-carbon Expo". Displacement sensor, also known as linear sensor, is a linear device belonging to metal induction. The function of the sensor is to convert various measured physical quantities into electricity. In the production process, the measurement of displacement is generally divided into measuring the physical size and mechanical displacement. According to the different forms of the measured variable, the displacement sensor can be divided into two types: analog and digital. The analog type can be divided into two types: physical property type and structural type. Commonly used displacement sensors are mostly analog structures, including potentiometer-type displacement sensors, inductive displacement sensors, self-aligning machines, capacitive displacement sensors, eddy current displacement sensors, Hall-type displacement sensors, etc. An important advantage of the digital displacement sensor is that it is convenient to send the signal directly into the computer system. This kind of sensor is developing rapidly, and its application is increasingly widespread. Magnetic Scale Linear Encoder,Magnetic Scale Encoder,Encoder Software,Encoder Meaning Changchun Guangxing Sensing Technology Co.LTD , https://www.gx-encoder.com
Among the 5.28 square kilometers of the park area of ​​the Expo Park, there are 29 public roads under the jurisdiction of the Shanghai Street Light Management Center. LED and related technologies have played a significant role in promoting energy saving and emission reduction in cities, and are considered to be the new solid-state cold light source with the most energy-saving and environmentally-friendly characteristics, but failed to enter the ranks of road lighting products in these 29 Expo sites.
Why does the Expo, which is based on "technology and low carbon", reject LED, a new type of solid-state cold light source that is energy-saving and environmentally friendly?
The trend of led street lights is PASS by the Expo Park
“In early 2008, the leaders of the Expo Bureau and the relevant professionals of the street lighting management department of the Shanghai Electric Power Company conducted many discussions on the design and construction of the streetlights in the Expo site. The leaders of the Expo Bureau have proposed the use of LED street lights for the streetlights of the Expo site. "Solar LED street light scheme." Wang Xiaoming, chief engineer of Shanghai Street Light Management Center, pointed out, "We conducted some investigations and technical analysis. We believe that the domestic LED streetlight technology was not mature at the time. The LED streetlights tried everywhere, the use of the scene is difficult. Satisfied, there is no LED street light product available for application. At that time, there were some problems with LED street lights."
The light effect is not high, the power supply (driver) fault is high, and the light decay is large, which is a common problem of LED street lamps at that time. In addition, the weight of the luminaire is too large, the structure is unreasonable, the color temperature is high, and the life is not long (not consistent with the number of 100,000, 50,000 hours). The enthusiasm of non-traditional street lamp manufacturers to promote LED street lamps is higher, and the lighting of lamps is reasonable. It is also the worry of the Shanghai Street Lamp Management Center.
"Solar energy utilization technology is also unsatisfactory, especially for batteries, which have short life and frequent replacement. Because the power of street lamps is relatively large, the capacity of the required batteries is relatively large. The weather in Shanghai is quite special. To meet the long-term lighting needs of street lamps. In recent years, the analysis of solar streetlights in some areas of Shanghai, such as Chongming, Songjiang and other places, did not meet the basic requirements."
After the above analysis, in 2008, the Shanghai Electric Power Company basically reached an opinion: the Expo Park should not promote the use of LED street lights; the solar street lights are technically unable to meet the basic street lighting requirements.