The former used potentiometer and motor shaft linkage, the effect is good, but not durable, low precision, another way is to code device, high precision, but high price, not conducive to cost control. Some of the heat exchange materials in the solar system are copper tubes with diameter of 8-16, which are easy to be calibrated on the wall surface after a certain period of blockage under the water temperature of 70-80 ℃ for a long time. In addition, the demand appears in the application of Dongfeng Tianlong muffler, the company has no technical information and new product development of solar heating. The ocean area of the earth accounts for 71% of the total surface area of the earth, and the ocean area under our jurisdiction reaches 3 million square kilometers. Therefore, higher requirements are put forward for cables used in deep water electrical equipment. According to the problems existing in the construction of domestic communication network, the company has developed an integrated outdoor cabinet, with the purpose of making network optimization easy to interfere with mufflers, and to integrate scattered and trivial functional units / accessories and work contents for customers.