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TODO: get_time, LCC timing description (e.g. saving next time stamp / listening to different timers)

The CPM timer is used to achieve a synchronized behavior across different devices that cooperate in the network. For example, all vehicles are supposed to publish their current state (like battery voltage) periodically at the same time. Such a behavior can be achieved with the CPM timer. Timing is either performed using the current real time (system clock, synchronized using NTP) or a fictitious time, which is distributed by a central timing instance.

Synchronization across all participants in the RTI DDS network is very important for all tasks that

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Real-time refers to the actual current time of the system, given by the system's current timestamp. To make sure that timestamps across different devices are comparable, NTP is used for clock synchronization on these devices. In a real-time scenario, all participants begin their computation (after being started either manually or by the LCC) at unix time 1 + period * n, where n is the smallest n such that the overall term is greater than or equal to the point in time when the timer was started. This assures synchronized periodic behavior for the registered components (using callbacks) across all devices. Real-time is useful whenever the system is used for real driving scenarios, to evaluate the system in a real-time use casee.g. when the actual physical vehicles are used.

The following drawing shows which role the LCC plays in the real-time timing case.

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