基于pelco sdk，实现了预览，抓图功能； 通过pelco-D协议，实现云台的上下左右，对角线运动及调焦和伸缩功能； 有串口编程和pelco-d协议的详细实现-Realize view and snapshot based on pelco sdk PTZ control have been designed, including com code and pelco-d code