基于PLC和CPLD的瞬时碰撞速度检测与应用研究

Instantaneous collision speed detection based on PLC and CPLD and its application

在汽车摆锤碰撞实验中,碰撞速度的检测与处理是影响实验结果准确性的关键因素。现有的一些速度采集装置利用单片机等微机系统实现计时,由于软件处理的延时往往导致计数精度不高、速度采集不准确。利用CPLD在处理高速信号上的优势,提出一种基于CPLD的硬件计时电路,其时间测量的分辨率达1μs,提高了测量的精度。并探讨了与PLC之间实现串行通信的硬件连接和软件实现方法,将原始值发送至PLC进行处理,计算碰撞瞬时速度。实验结果证明,该方法成功地实现了CPLD与PLC的串行通信,可以准确测量瞬时速度,并且具有开发简单、抗干扰能力强等特点。

In pendulum impact experiment of cars,the detection and processing of collision speed are the key factors influencing the accuracy of experimental results. Some existing speed acquisition devices have low computational accuracy and inaccurate speed acquisition due to the delay of software processing,in which the single-chip microcomputer system is used for timing.The advantage of CPLD for high-speed signal processing is adopted to propose a hardware timing circuit based on CPLD. Its resolution of time measurement can reach up to 1 μs,and the precision of time measurement is improved. The hardware connection of serial communication between CPLD and PLC and software implementation method are discussed,and the original value of CPLD is send to PLC for processing to compute the instantaneous collision speed. The experimental results show that the proposed method can implement the serial communication between CPLD and PLC successfully,and measure the instantaneous speed accurately,which has the characteristics of simple exploitation and strong anti-interference ability.