A built-in clock used for a wide variety of program-timing purposes. It can be used to log the receipt times of periodic real-time input data. Each input message and its receipt time may be recorded together.

• 一种内部时钟，广泛用于多种程序的定时。它可以用来记录周期性的实时输入数据的接收时间，每项输入信息及其接收时间都可以一起被记录下来。