自动控制原理-英文论文.docx

Automatic Control Applications In the social life 班级： 学号：姓名： Programmablecontrollertocontrolwater supplysystemConstant pressure water supply system for a certain industry or a particular user is very important, for example in certain production processes, if the tap water supply or short-time shortages due to insufficient water, which may affect product quality, serious product scrap and damage to the equipment. When a fire occurs, if the water pressure is insufficient or no water supply, no rapid fire, can lead to significant economic losses and casualties. So some of the water area with constant voltage water supply system, has great economic and social significance.Mechanical technologyOld pressurized equipment, General starts or stops using constant-pressure water supply pressurizing station exit of pumps and regulating valve opening is to be achieved. Control system is the use of relay-contactor control circuits, this line complex, difficult to maintain, and operate trouble, workers to guards on duty 24 hours, labor intensive. It is necessary to reform, improve the level of automation.Electrical technologyPresented to a tap water pressure station quick starting of constant pressure water supply control system, the FP3 produced by Matsushita programmable logic controller (PLC) controls with Advantech industrial computer monitor, high degree of automation, the whole program to work automatically, clearly shows the real-time status of each device, and automatically adjust the water pressure. The system also has a wide range of protection, such as water pressure alarm fault alarm, water alarm, valves, pump motor current flow and processing alarm processing and so on.System structure and control requirements of mechanical and electrical engineering technology network，Constant pressure water supply system consists of the main loop, the alternate loop of water supply,Composed of 2 water tank and pump house, as shown in Figure 1.Pumping station equipped with a 1# 6# a total of 6 sets of 150kW pumps. There is more than one (V1 V23) electric valve controls the water circuit and the flow of water.Requires the constant pressure water-supply system has the following basic operating functions.Electrical technical machinery technolog.When municipal water pressure is higher than the setting pressure 21.56x104Pa, directly by the municipal water supply in electrical technology. When city water is lower than the set pressure, but under the pressure of not less than 7.84x104Pa when using direct pumping pressurized water supply solutions. Of progressively starting 2 pumps to pipe network pressure. When city water higher than the set pressure is detected, then converted to city water supply directly. When the tap water pressure is lower than 2.94x104Pa, or when there is a negative pressure signal exactly, should immediately convert water pressure, but should ensure that the pool water level above the minimum water level conditions. Mechanical technology.When pumping or pumping water pressure water supply is used, should be able to automatically adjust the water pressure for a given value of its total exports, control deviation is less than or equal to 10%. Electrical technologyCAD/CAM technologyDesign of PLC control system CAD/CAM technologyConstant pressure water supply system for detection and control of more is a large control system. According to its characteristics, we have chosen Panasonic FP3 programmable controller is a controller. The controller with it can programming sequence controller compared to, has some obviously of advantages, as FP3 used has module of design, can according to actual needs flexible assembled, using convenient, I/O distribution used free programming way; capacity big, program volume only by scan cycle limit, and scan cycle can in must range within itself change; has A/D, and D/A, and pulse output, and location control, senior unit, can achieved shared memory; addition also some special of function. Mechanical technologyConstant pressure water supply system of PLC system structure is shown in Figure 1-dashed border. Industrial computer to monitor the entire system, the display shows the total pressurized system structure, read the real-time status of each valve and pump, water pressure and flow rate, the valve opening, the pool water level and other parameters, and real-time display alarm and fault record.Electrical technologyBoth analog input and switch input. Analog by a/d module input, total 27 channels. There are 96 I/O points.CAD/CAM technologyMechanical technologyPLC software designElectrical technologyAccording to constant pressure water supply system operational requirements, PLC control system to monitor City tap water, and water has to decide whether to start the water pump, or direct water pumping programme or by pumping pressurized water full solution. Control system the procedure is more complex. Electrical/mechanical engineering technology networkIn the control process, water supply and pressure regulation is an important and one of the more distinctive design, focusing on software design of automatic constant-pressure function.Due to the large water system piping length and diameter, the opening and closing of the valve, pipe network pressure is slow, so the system is a system with large time delay. And because it is based on the old equipment transformation, to make use of existing equipment, it does not use speed regulator, instead of using the various methods to adjust the water pressure. First used segment regulation method, put hydraulic deviation is divided into four segment, that 10%, and 20%, and 30%, and 40%, dang detection to deviation smaller Shi, output of control volume (butterfly valve of incremental) smaller, and operation cycle also larger; In addition, when the deviation is less than or equal to 10%, coupled with the fuzzy control, according to d EK=EK-EK-1 to determine whether regulating butterfly valve opening, to further reduce the errors to ensure its error less than or equal to 10% requirements. Pressure is regulated