一.　　实验目的：

1.了解光电开关的使用方法

2.了解利用光电传感器测量电机转速的方法



二.光电测速基本原理

光电测速的基本电路由光电传感器、计数器和定时器组成。测量时在被测电机主轴上固定一个圆盘，圆盘的边缘上打上小孔。传感器的红外发射端和接收端装在圆盘的两测，电机带动圆盘转到有孔的位置时，红外光通过，红外接收管导通，输出低电平。红外光被挡住时接收管截止，输出高电平。用计数器记录在一定时间内传感器发出的脉冲个数就可以计算出电机转速。



三.实验内容

1.接线方法：直流电机计数端接8253 CLK1；8253 CLK0接1MHZ脉冲；OUT0接CLK2；OUT2接8255的PA0；GATE0、GATE2接+5V；GATE1接PC0；8253 CS接280H；8255 CS接288H；DJ接电位器RW1的中间头。

2.编程：利用8253定时器1记录脉冲个数，8253定时器0和定时器2组成10～60秒定时器，测量在一定时间内脉冲个数，算出电机每分钟转速，显示在屏幕上。-1.Understand the operation method of optoelectronics switch

2.The method understood to make use of optoelectronics to spread a feeling machine to measure electrical engineering to turn soon



Two.The optoelectronics measures soon basic principle

The optoelectronics measures soon basic electric circuit to be spread a feeling machine by the optoelectronics, count a machine and in fixed time the machine constitute.Fix a disk in being measured an electrical engineering principal axis while measuring, beat eyelet on the edge of disk.The red outside blast-off that spreads a feeling machine carries and receives to carry to pack in the disk of two measure, when the electrical engineering arouses a disk to turn to the position of having the bore red outside and only pass, red circumscribe to accept a tube to lead, output low electricity even.Red receive a tube to close while outside and only being held up, output Gao Dian Ping.Use to count a machine record in certain time inside spread the p