US 7,619,322 B2 · Two-wire power and communications for irrigation systems

Abstract

A large number of irrigation system devices connected to a common two-wire cable can be powered and individually controlled from a central location by transmitting over the cable DC pulses of alternating polarity. Control information is conveyed by transmitting a command pulse train consisting of a series of pulses, separated by short no-power intervals, whose polarities indicate logic ones or zeros. Following a command pulse train, a selected watering station decoder acknowledges receipt of instructions by drawing current during a predetermined pulse of an alternating-polarity power pulse cycle, while a sensor decoder returns binary data by drawing current during one or the other of the alternating-polarity pulses of a series of power pulse cycles.

Claims18

Dependent claims

A method of providing power and communications to a plurality of remotely controllable devices over a single pair of wires in a control system, comprising the steps of:

connecting to said pair of wires a plurality of devices selectably actuatable to perform a predetermined function in response to an identification and action code;
transmitting over said pair of wires direct current power pulses of alternating polarity for powering said devices;
each of said power pulses having a first width and either a first polarity or a second polarity;
each of said power pulses delimited from each other by a no-power segment;
actuating a selected one of said devices by transmitting said identification and action code over said pair of wires in the form of a train of communication pulses that have said first polarity for logic 1, and said second polarity for logic 0;
and
causing said selected device to acknowledge receipt of said code or transmit data in response thereto by selectively drawing current in the presence of a transmitted pulse of predetermined polarity.

4 more elements

Dependencies are inferred from the claim text.

Two-wire power and communications for irrigation systems

Life of this patent

Two-wire power and communications for irrigation systems

Life of this patent

Abstract

Claims18