We inherited this wonderful sprinkler system when we moved in but it did not come with a manual. It goes around the cycle within the increments of time for each zone but does not shut off at the last zone. It just starts all over again. If I did not turn it off, I am sure it would go on forever rotating through the zones.
If the total running time of all the zones isn't at least half an hour, or thereabouts, the cycle will repeat. This is because the hour-of-the-day pin that started the cycle hasn't yet moved away from the start position.