A system for controlling the operation of a moving irrigation system lengthens the period of the on-and-off cycle specified by the speed timer to drive the pivot arm assembly. This reduces the frequency of the on-and-off cycles and thereby reduces wear and tear on the drive components. To modify the cycle period, a processor determines a modified on-time and a modified off-time having the same ratio of on-time to off-time as the speed timer to maintain the same average speed for the pivot arm assembly. The processor then controls operation of the pivot arm assembly to move in an on-and-off manner using the modified on-time and modified off-time.
