| CPC A01G 25/165 (2013.01) [G05B 19/042 (2013.01); G05B 2219/2625 (2013.01)] | 23 Claims |
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1. A decoder unit for an irrigation system that receives power and data from an irrigation control unit over a multi-wire path, the decoder unit comprising:
an input interface configured to couple to the multi-wire path of a decoder-based irrigation control system and to receive an output AC signal modulated with the data and transmitted by an encoder of the irrigation control unit over the multi-wire path;
a switch coupled to the input interface and configured to couple to a solenoid of an irrigation device;
a decoder circuit connected to the input interface and comprising a decoder circuit control circuit, wherein the decoder circuit control circuit is configured to:
decode the data from a received output AC signal input to the decoder circuit;
determine, from the decoded data, that the irrigation device is to be activated; and
output a control signal to the switch to cause the switch to close and connect the output AC signal to the solenoid; and
a current measure circuit coupled to the switch and configured to measure a current of the output AC signal passing through the switch and being drawn by the solenoid and provide a first output signal comprising a measure of the current to the decoder circuit control circuit;
wherein the decoder circuit control circuit is further configured to determine, based on the measure of the current, whether the solenoid is operating properly or whether a ground short condition exists, wherein the current measure circuit is further configured to measure the current of the output AC signal passing through the switch after a predetermined time delay following a closing of the switch to account for an initial inrush current passing through the switch.
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