| 摘要 |
An improved irrigation control system of the type having a number of irrigation stations to be actuated sequentially, in which selected stations can be actuated for a relatively long time and the others for a relatively short time. In one embodiment, an additional capacitor is automatically connected in parallel with an existing timing capacitor at a time when shrub-watering stations requiring long-term irrigation have been scheduled for operation, when the system is positioned at a shrub-watering station, and when a switch is positioned to select long-term irrigation. In another embodiment, an additional capacitor is automatically connected in parallel with the existing timing capacitor when any one of a selected group of stations is actuated. The additional capacitor in this latter embodiment is switched in by means of a relay which is energized through a triac connected in series therewith, the triac being triggered by a gating signal derived from an actuating voltage applied to a valve solenoid associated with any of the selected group of stations.
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