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Digital two-wire irrigation control system with feedback

  • US 4,131,882 A
  • Filed: 12/29/1975
  • Issued: 12/26/1978
  • Est. Priority Date: 12/29/1975
  • Status: Expired due to Term
First Claim
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1. For use in a digital control system in which an alternating-current power signal and control signals formed by selective suppression of part of the power signal are transmitted along the same conducting lines from an encoder, decoding apparatus comprising:

  • means for decoding control signals, said control signals including decoder addresses and on/off codes, and said means for decoding including rectifier means for separating said control signals from the alternating-current power signal by detecting selective suppression of the power signal;

    means for compraring received decoder addresses with an address associated with said apparatus;

    means for operating at least one switchable device in accordance with a received on/off code if said means for comparing finds a match; and

    means for transmitting to the encoder, during a temporary interruption of the power signal, a feedback signal corresponding to the state of the switchable device after being operated in accordance with said received on/off code, if said means for comparing finds a match.

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