2024-05-15

IC693PWR321 PLC control system and intelligent central air conditioning

IC693PWR321 PLC control system and intelligent central air conditioning

Because of its application significance in industrial control, PLC has been widely used in the electrical control of process equipment in power generation, chemical industry, electronics and other industries. It has many advantages such as powerful function, easy use, simple maintenance, and has gradually replaced the logic control of relay circuits in many places. At the same time, intelligent central air conditioning is also being widely used, in the case of the IC693PWR321 combination of the two, not only to promote the development of science and technology, but also to improve people’s living standards.

1.1 Introduction

With the continuous development of China’s economy, the society is highly informationized, and new high-tech technologies are constantly applied to all aspects, making intelligence has become an inevitable trend of development. Intelligence also often starts with equipment automation systems. This paper mainly for our graduation project “intelligent small central air conditioning” elaborated the PLC control design and intelligent central air conditioning (freezing station) system relationship.

1.2 Introduction to the system and process

IC693PWR321 Here is the introduction: Our design has two sets of central air conditioning system, by three cooling water pumps, three freezing water pumps, a cooling tower fan, two chiller and other main equipment composed of two sets of refrigeration system (because the system is small, cooling tower power, laboratory requirements, etc., the system is different than the general two sets of refrigeration system is two chiller but only choose a cooling tower, after calculation and approval, This does not affect its effect) in which the chiller is supplied in complete sets by the equipment production plant. According to the laboratory requirements of this design, we chose 2*5 fully enclosed compressor chiller. It is generally automatically controlled by a microprocessor according to the principle and law of air conditioning. The chiller consists of a compressor, a condenser and an evaporator. The compressor compresses the refrigerant, and the compressed chiller enters the condenser, is cooled by the cooling water, and becomes a liquid. The heat precipitated is taken away by the cooling water and discharged into the atmosphere in the cooling tower. The liquid refrigerant evaporates into the evaporator through the condenser to absorb heat, cooling the chilled water, and then the chilled water enters the chiller coil to absorb the heat in the air. This cycle continues to bring the heat out of the room to achieve the purpose of reducing the ambient temperature. Therefore, the process control requirements of the central air conditioning freezing system are:

(1) Measure the temperature and flow of chilled water supply and return water, so as to calculate the actual cooling load of the air conditioner, according to the actual cooling load to determine the number of chiller to open, to achieve the best energy saving state.

(2) The program linkage of each equipment: start: cooling tower fan — cooling water pump — freezing water pump — chiller. Stop: chiller — freezing water pump — cooling water pump — cooling tower fan. When one of the cooling water pumps or chilled water pumps fails, the standby cooling water pump or chilled water pump automatically starts working.

(3) Measure the pressure difference of IC693PWR321 the refrigerated water supply and return pipe △P=P1-P2 Control the opening of the bypass valve (TV) to maintain the pressure difference.

(4) The purpose of this laboratory design is to give students a more vivid learning and understanding of the central air conditioning system, so in the design process, we will also take into account the appropriate and important position to install a scope for observing refrigerant or water flow.

1.3 Principle and application of PLC

IC693PWR321 There are three control methods for central air conditioning freezing system: early relay control system, direct digital controller DDC and PLC(Programmable logic controller) control system. Due to the high failure rate, complex system and high power consumption, the relay control system has been gradually eliminated by people, although the direct digital controller DDC has made great progress in intelligence. However, due to the anti-interference ability of DDC itself and the limitation of the hierarchical step structure, its application range is limited. On the contrary, the PLC control system is widely used because of its easy operation, convenient use and maintenance, strong anti-interference ability, and suitable for new high-speed network structures.