Design Of Dyeing Temperature-control System

It is necessary to adopt special dyeing heating curve for the given dyeingtechnology in the dyeing process. Temperature-controlling precision of the liquidin the dyeing jar plays an important role in the dyeing process, which has directeffect on the dyeing objects. The more accurately the temperature of dyeingliquid is controlled, the brighter the color of the dyeing objects will be and thelonger it will be kept. Otherwise, the dyeing objects will be dark and fade rapidly.Traditional dye usually controls the flow of heat vapor or cold vapor, manually, tochange the temperature of the dyeing liquid. Therefore, its automation is lower,its dyestuff wastes more, dyeing quality is worse and far from meet socialdevelopment and the need of people’s lives.To solve the problem in the dyeing industry and realize low carbon andenvironmental protection, saving energy and carbon emission reduction,time-saver and highly efficient, stability and reliability, the dyeing systemcombines the master PC with slave hardware module and applies RS485bus torealize one master PC to control plenty of slave hardware modules. The masterPC puts use of labVIEW(Laboratory Virtual Instrument Engineering Workbench)to program, whose function is instruction transportation, temperature set, save,alarm and so on; The slave module’s function is mainly carrying out instruction,temperature acquisition, checking out the position of liquid, alarm and so on. Themaster PC and the slave module cooperate to realize closed-loop control viaRS485bus.The master PC sends the given temperature value to the slave MCU, at thesame time, the slave MCU receives the temperature and begin to control heatingpower keeping the liquid temperature in the jar up or down. Temperaturesensor-PT100transfers liquid temperature value in the jar every one second to themaster PC and draw the value in corresponding position. Meanwhile, the PIDalgorithm computed the next heating power on the basis of the value of the real temperature and the given temperature to make the precision swing betweenpositive one and negative one degree centigrade. Also, the slave module’sfunction is responsible for switching value such as controlling or checking drainvalve, inlet valve, etc. When the liquid position exceeds the safe liquid position,the whole system sends alarm signal and inform the worker to take steps.4-20mAcurrent technology is applied in the slave module. Therefore, signal transfersmore stable and reliable than volt whether in the distance or in theanti-interference. After a long time of debug, analysis, the whole system realizestemperature tracking, liquid level detection, power controlling, many dyeingmachines total distributed control, measure precision±1°C, temperaturecontrolling precision±1°C, closed-loop control and automation control.