in industrial production control system, there are many needs time to complete t...

在工业生产控制系统中，有许多需要定时完成的操作，如定时显示当前时间，定时刷新屏幕上的进度条，上位 机定时向下位机发送命令和传送数据等。特别是在对控制性能要求较高的实时控制系统和数据采集系统中，就更需要精确定时操作。-in industrial production control system, there are many needs time to complete the operation, such as the timing shows the current time, regularly updated progress on the screen of the PC regular crew sent down orders and transmit data. Especially in the control of the high performance requirements of real-time control system and data acquisition system, the need for more precision timing operation.