Aiming at the deficiency of current sampling gas flow control for porphyrin sensor gas detecting system, a flow control system with high precision, fast response and small overshoot is presented. The system adjusts the duty ratio of PWM pulse signal using increment PID algorithm, then it can change the amplitude of armature voltage for DC motor indirectly, so it can control sampling gas flow. The flow control precision is ±1.5 cm /min, and gas flow can reach stability only in 15.6 s with the help of the flow control system. The experimental results show that flow control of sampling gas is helpful to detect target gases accurately and quickly for the porphyrin sensor gas detection system.%针对目前卟啉传感器气体检测系统中采样气体流量控制的不足,提出了一种控制精度高、响应速度快、超调量小的流量控制系统.该系统利用增量式PID算法调整PWM脉冲信号的占空比,从而间接地改变直流电机两端电枢电压的大小,实现对采样气体流量的控制.流量控制精度为±1.5 cm3/min,且气体流量仅需15.6s就能达到稳定.实验结果表明:控制采样气体流量,有助于卟啉传感器气体检测系统准确、快速地实现对目标气体的检测.
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