To Implement Auto-control Sugar Separation Machine By Using PLC And Its Vibration Protection

There are many sugar factories in GuangXi Autonomy.which have a large outputBut most sugar factories still use completely hand-controled Sugar Separation Machine. The hand-controled Sugar Separation Machine not only has low productive efficiency but also results in unstable product quality.Under market economy conditions, productive efficiency and product quality are extremely important to an enterprise ,so for every sugur factory the technical innovation in Sugar Separation Machine is badly neededUsually, the methods to improve the Sugar Separation Machine with auto-control include: 1 .industrial control computer. 2 jnicrocontroDer.3. PLC.Industrial control computers have the ability to develop by themselves and their ability of anti-disturbance is strong.But they are so expensive that it is dearly a waste to use industrial control computers in small-scale auto-control system.Microcontroller is cheap, but it is not easy to design a auto-control system with microcontroller which can operate steadily and reliably in bad electromagnetic and weather environment A famous institute once improved the control system with microcontofler,but the result was not satisfactory.PLC has a lot of advantages such as small volume,strong function^imnle progTammmg,phanc\;aO-purpose application and convenient maintenance. It also has high reliability and adaptability to operate in bad industrial errvironmentSo PLC is applied widely.Sugar Separation Machine usually operates in bad environment and it's control system has to work reliably in such environmenlTaking the factors such as technology and price into OMsideration,we finally choose PLC for the innovation.Automatic Sugar Separation Machine is a kind of rotatory machine.Because of unavoidable errors in the course of manufacture, installation,and the inhomogeneity of material distribution especially when the material is running out ,deflection between rotor's central axis of inertia and it's axis is unavoidable.The mhomogeneiry of material distribution is main reason for the deflection. According to mechanicsf axis isn't rotor's central axis of inertia, shaft bearing win generate additional dynamic counterforce and it's direction will change with axis,generating periodically varying pressure and causing mechanical vibrations.lt is difficult to solve the problem of mechanical vibrations in the way of mechanicso the sensitivity of detecting mechanical vibrations force must be reinforced .When vibration force exceeds preset threshold, PLC's control programme executes a series of operation to protect mechanical system and driving motor. So it is very important to design and make high sensitive vibration measurement PCB.The sensor on the PCB is high sensitive acceleromoter ADXL202 which is manufactured by Analog Devices Corporation,U.SAThe sensor's output is digital signal ,whose duty cycle is proportional to me acceleration in each of the 2 sensitive axes. The microcontroller AT89C2051 is used to measure pulse width and compare the result with preset thresholdjf it is greater than or equal to the threshold, the microcontroller sends the high level to PLC and makes it execute protection operation.