Patent ID: 7406363

Claim:
An irrigation controller, comprising: at least one control node; valve actuation control circuitry electrically coupled to the at least one control node for generating a valve actuation control signal on the at least one control node over an actuation period, wherein the valve actuation control signal comprises a plurality of control signal periods each having a continuous control voltage, whereby the valve actuation control signal continuously energizes the at least one control node, a control wire, and a valve coupled to the control wire over the actuation period; and valve chatter circuitry electrically coupled to the at least one control node for generating a valve chatter control signal on the at least one control node, wherein said valve chatter control signal comprising a plurality of duty cycles, each duty cycle comprising one control signal period and at least one naught signal period, said control signal period comprising a first voltage over a first portion of the control signal period and a second voltage over a second portion of the control signal period, and said at least one naught signal period comprising the second voltage, wherein the second voltage is less than the first voltage, whereby the valve chatter control signal intermittently energizes the at least one control node, the control wire, and the valve coupled to the control wire over the chatter period.