Abstract: A control system and method for an automatic sprinkler system is disclosed. The automatic sprinkler system includes a first control line and a common line coupled to control a first valve. The control system includes a relay coupled in series with the common line, a sensing circuit coupled to detect the assertion and deassertion of the first valve, and a controller coupled to receive a control data. The controller provides a control signal to enable the relay based on the control data. In operation, the relay is turned on or off based on the control data for controlling the on/off duration of the first value. The relay may be incorporated in the sprinkler system. In one embodiment, the control system learns the programming of the sprinkler system by monitoring the common line to determine the start time, the duration, and the irrigation frequency of the first irrigation zone.