请问各位大侠,像下图1这样连接,通信正常(可以接收和发送),说明程序和硬件没问题吧?但如果把图1的光耦(801 P521 GR)换成图2的接法(光耦由发送端换到接收端),就通信不上了?请问这是什么原因呢?光耦我用导线把它引出来接,这方便我更换,且保证光耦是同一个光耦.我分析了好几天了,实在是找不出问题的根源啊!!电源我加多了下个“派”型漓滤了,电阻等参数我也换过了,但就是不行!真是极度郁闷啊!!
还有一个问题,就是把图1的光耦换成(746 P521 GB)的话同样是通信不上!!理论上来讲这两个光耦可以互换啊!!
![](http://u.dianyuan.com/bbs/u/71/2992531225704867.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20)
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图,点击可放大。\n按住CTRL,滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/71/2992531225704867.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">
图1
![](http://u.dianyuan.com/bbs/u/71/2992531225704896.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20)
500) {this.resized=true; this.width=500; this.alt='这是一张缩略图,点击可放大。\n按住CTRL,滚动鼠标滚轮可自由缩放';this.style.cursor='hand'}" onclick="if(!this.resized) {return true;} else {window.open('http://u.dianyuan.com/bbs/u/71/2992531225704896.jpg?x-oss-process=image/watermark,g_center,image_YXJ0aWNsZS9wdWJsaWMvd2F0ZXJtYXJrLnBuZz94LW9zcy1wcm9jZXNzPWltYWdlL3Jlc2l6ZSxQXzQwCg,t_20');}" onmousewheel="return imgzoom(this);">
图2
谢谢各位,急救啊!!