Two-wire power and communications for irrigation systems
First Claim
1. 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.
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Accused Products
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.
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Citations
18 Claims
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1. 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:
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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. - View Dependent Claims (2, 3, 4, 5)
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6. Apparatus for simultaneously powering and controlling selected components of an irrigation system over a single pair of wires, comprising:
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a) a plurality of decoders connected to said wires and arranged to be powered by a potential thereon; and b) a communication system for selectively bringing a first of said wires to a positive potential, a negative potential, or an equal potential with respect to the other of said wires; c) said decoders being responsive to predetermined sequences of said potentials to actuate system components connected thereto;
said predetermined sequences of potentials communicating a plurality of data bits based on a level and polarity of each of said potentials;d) wherein control information is transmitted to said decoders by transmitting a series of potential pulses separated by intervals of equal potential on said wires, the polarity of said potential pulses defining a “
1”
or a “
0”
. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification