PID Parameters Adjustingand Optimization Tuning Assistant By Upper Computer

With the development of microelectronics technology, and the emergence of very largescale integration wafers(namely SCM), intelligent instrument has been developing rapidly.However, with the development of intelligent instrument being more and more mature,theoperation interface is more and more simple. Usually, an operation platform can be formed bykey, LED display and indicater, which undoubtedly will bring difficulty to later debugging ofequipment.The proposal of this topic is to provide a good and completed operation interface forintelligent instrument, so that it is convenient to adjust its intrinsic parameters.This subjectchooses melting point instrument as its research object,designing a kind of temperature controlsystem of PID parameters adjusting assistant by upper computer,aiming at adjusting PIDparameters during the rapid heating and uniform velocity heating process.The melting point instrument chooses MSC1210Y5microcontroller as the core control chip.The temperature control system mathematical model is established based on the hardwareplatform, and used to design the upper computer and lower computer program. Single chipcomputer adopts C language as programming language, and Keil as development environment.Upper computer adopts LabVIEW as programming language, being used to graphically displaytemperature data uploaded from single chip computer, at the same time real-time adjusting PIDparameters through observing temperature curve, until achieving satisfactory heating process.At the side of program development of single chip computer, this topic adopts the way thatmain program and interrupt program run in conjunction. The main functions include realizingtemperature acquisition, data operation and processing, temperature display, constanttemperature and uniform velocity heating control, etc.In the control of temperature, position-type PID algorithm is used to control constanttemperature and uniform velocity heating. The melting point instrument’s part of output power isused to heat up, and the other part is used for heat dissipation. The heating process is related tomaterial’s heat capacity, and the heat loss process is related to the heat dissipated powercoefficient. Because of the two coefficients are inherent in the system, the PID parameters got by tuning should match them. Therefore, before the PID parameters tuning, it is necessary tomeasure the system’s inherent parameters--the heat capacity and the heat dissipated powercoefficient.When adjusting PID parameters with the assistance of LabVIEW, the first thing is to specifythe communication protocol between MCU and PC, and use the VISA module to make serialcommunication with single chip microcomputer. Then, LabVIEW make timely adjustmentsaccording to the temperature value sent by MCU, until get the proper parameters finally. Withthe help of LabVIEW, the change of temperature curve will be observed intuitively. In this case,the complexity of debugging and the blindness of parameters tuning will be reduced, at the sametime the adjustment period of PID parameters will be shorten.