Research And Application Of The Constant Temperature Dryer

PLC is a microprocessor as the core of digital computing operations, specially designedfor the electronic system device in industrial field application and design, it USESprogrammable memory in its internal storage, to perform the logic operation, sequencecontrol, regular/counting and arithmetic operation instructions, and through digital or analoginput and output interface, control the various types of machinery or production process. PLCis with traditional microcomputer technology relay contact control product of combining thecharacteristics it overcomes the relay contact control system of the complex mechanicalcontacts, low power consumption, high reliability, and the poor quality of universality andflexibility, make full use of the advantages of the microprocessor, and take care to siteelectrical operation maintenance personnel skills and habits, adopted a set of to relay thesimple instructions based trapezoid the forms, the user programming image, intuitive,convenient easy, debugging and error-checking is also very convenient.PLC is variety, but its composition structure and working principle basically is same. Byprogrammable controller, its essence is implementing control input and output by certainalgorithm conversion, and will these transform to physical implementation, applied to theindustrial field. PLC designed for industrial field application and design, using a typicalcomputer structure, it mainly consists of CPU, power, storage and special design ofinput/output interface circuit etc.Use Siemens S7-200PLC based controller, Coupled with human-machineinterfaceTD400C and Communication Module. EM277. Dryer designed temperature controlsystem, Temperature, humidity, the collection frequency output by the sensor/transmitter.The frequency signal integrated high-speed access to PLC input pulse, Timer counts to obtainsamples. Control command from the digital input interface. TD400C access; system operationcan also be in the digital output interface, TD400C display. Field application shows that thesystem is reliable, easy to use.