Center pivot irrigation system control

摘要

A control apparatus is disclosed for use in an irrigation system having a plurality of conduit sections pivotally joined at sets of adjacent ends and selectively operable drivers for moving the conduit sections in a forward direction. Each control apparatus maintains the relative alignment of a pair of joined conduit sections. It includes a conduit misalignment indicator having two indicating portions which are directly relatable in position to the relative alignment of the two conduit sections. Further, Hall-effect sensors positioned on one indicating portion opposite from a magnet positioned on the other indicating portion provide for sensing of the relative alignment of the conduit sections. A digital electrical circuit converts the sensor signals into a control signal for initiating operation of the driver when the conduit sections are in lagging misalignment and terminating operation when the conduit sections are in leading misalignment. The apparatus may be used with a direction indicator to initiate operation of the driver when the conduit misalignment exists for the given direction of travel. Also, the two indicating portions may be disposed on a misalignment multiplier which increases the sensitivity of the apparatus to the relative alignment of the two associated conduit sections. Time delayed circuitry is also provided for terminating operation of the irrigation system when the conduit sections are in excessive misalignment.