摘 要本论文要做的课题是基于虚拟仪器的加热炉温控系统设计，要求加热炉温度稳定在 80℃，允许有±1℃的误差。本论文采纳美国 NI 公司虚拟仪器开发软件 LabVIEW8.5 开发出一套低温电加热炉温度控制系统。系统具体设计方案如下：由传感器测得的炉温信号经过变送环节送给数据采集卡，采集卡对信号进行 A/D 转换后传输至虚拟仪器，虚拟仪器中的 PID 算法对信号处理后产生控制信号，再经过采集卡D/A 转换后输出控制 PWM 波产生电路，改变 PWM 波占空比，产生的PWM 波经过光耦 MOC3041 控制双向可控硅的通断，以此改变加在电阻上的电压，达到温控目的。本论文首先根据上述设计方案设计了硬件电路，接着进行系统软件的设计。经过简单的实验，系统可以正常采集数据并显示。关键词：虚拟仪器，LabVIEW，温控系统，过零调功，PWMAbstractThe task of this paper is to design a temperature control system based on virtual instrument of the furnace.And the requirements of the furnace temperature is stable at 80, allowed error of ± 1.℃℃This paper adopted LabVIEW8.5, a software to develop the virtual instrument of NI company in America,developed a set of temperature control system of low-power electric heating. The system design are showed as follows: the temperature sensors send the signal of temperature change to the data acquisition card by transmitter, then the signal will be convert to digital signal and be send to the virtual instrument by the data acquisition card , and then the virtual instrument will output control signal after be processed by PID algorithm, and the control signal will be convert to analog signal by the data acquisition card and output to control PWM waves produce circuit to change the duty cycle of PWM waves, then the PWM waves will control the bidirectional thyristor through opticalcoupler MOC3041 to change the voltage in resistance so that the temperature will be changed.This paper designed the hardware circuit in...
