Digital two-wire irrigation control system with feedback
First Claim
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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Accused Products
Abstract
A method and apparatus for the control of a number of valves in an irrigation system utilizing only two lines between a central encoder and a number of remotely located decoders. An alternating-current signal on the lines is used both to transmit power to the decoders and valves, and to convey control information in the form of decoder addresses and on/off signals represented in binary form by selectively clipping the alternating-current signal. The encoder includes timing and switching circuitry to effect temporary interruptions of the alternating-current signal, and to detect feedback signals transmitted from the decoders during the interruptions. At each decoder, the received control signals are recovered from the power lines, and each received decoder address is compared with one which identifies the decoder. When a match is found, the received on/off signal is employed to switch a valve and to initiate transmission of a confirmatory feedback signal. A portable operator, which may be connected to the power lines anywhere in the system, monitors the control signals transmitted from the encoder, and transmits special feedback signals which direct the encoder to perform functions selected at the portable operator.
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Citations
35 Claims
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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:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. For use in a digital irrigation control system in which both alternating-current power and control signals are transmitted along the same conducting lines to a number of decoders, and confirmatory on/off feedback signals are transmitted back from the decoders, encoding apparatus comprising:
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means for encoding and transmitting blocks of control information, including decoder addresses and on/off codes, onto the lines, by selective suppression of part of the power signal; means for detecting confirmatory on/off feedback signals from the decoders each feedback signal being transmitted during a temporary interruption of the power signal following each corresponding transmission of a block of control information; and means for storing and displaying information contained in said feedback signals as an indication of on/off status conditions at the decoders. - View Dependent Claims (9, 10, 11, 12)
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13. A digital irrigation control system in which an alternating-current power signal and control information are transmitted along the same conducting lines, said system comprising:
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encoding means for encoding and transmitting blocks of control information, including decoder addresses and on/off codes, onto the lines, said encoding means being operable to selectively suppress part of the alternating current power signal and thereby to encode the control information; decoding means for recovering the blocks of control information from the conducting lines, comparing each recovered decoder address with an address associated with said particular decoding means, and operating at least one valve in accordance with received on/off codes addressed to said decoding means; means coupled with said decoding means, for transmitting, during intervals of temporary interruption of the power signal, feedback signals corresponding to said on/off codes addressed to said decoding means; means coupled with said encoding means, for detecting said feedback signals received following transmissions of blocks of control information; and means for storing and displaying information contained in said feedback signals as an indication of on/off status conditions at the decoders. - View Dependent Claims (14, 15, 16)
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17. For use in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of remote decoders, for the control of a plurality of switchable devices, portable control apparatus connectable to the conducting lines to control the switchable devices in conjunction with the encoder, said apparatus comprising:
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means for decoding control signals transmitted by the encoder; means responsive to decoding of control signals addressed to said portable control apparatus, for transmitting feedback signals of a first type to the encoder to indicate that said portable control apparatus is connected to the lines; manually operable means for selecting which decoders are to be manually controlled; and means for transmitting feedback signals of a second type to the encoder to indicate which decoders are to be manually controlled from said portable control apparatus; whereby the transmission of control signals from said encoder is controlled by said portable control apparatus so long as said apparatus is connected to the lines. - View Dependent Claims (18)
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19. For use in a digital irrigation control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of remotely located decoders, for the control of a plurality of switchable valves, apparatus for the control of said system from any desired location, said apparatus comprising:
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portable control means connectable to the conducting lines to control the switchable valves in conjunction with the encoder, said portable control means including means for decoding control signals, including decoder addresses and on/off codes, transmitted from the encoder, means responsive to decoding of control signals addressed to said portable control means, for transmitting feedback signals of a first type to the encoder to indicate that said portable control means is connected to the lines, manually operable means for selecting decoder control functions, and means for transmitting feedback signals of a second type to indicate control functions to the encoder; and control means included within the encoder and including means for detecting feedback signals of the first type and thereby determining whether said portable control means is connected to the lines, means for decoding feedback signals of the second type, and means for selecting for transmission on/off codes as determined by said feedback signals of the second type instead of as determined by a normal preselected sequence of valve operations. - View Dependent Claims (20, 21, 22, 23)
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24. A digital irrigation control system in which both power and control signals are transmitted along the same conducting lines to control a plurality of switchable valves, said system comprising:
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at least one decoder for decoding control signals, including decoder addresses and on/off codes; means at said decoder for transmitting feedback signals of a first type indicating that an on/off code addressed to said decoder has been received; portable control means connectable to the conducting lines to control the switchable valves, said portable control means including means responsive to control signals transmitted along the lines and addressed to said portable control means, for transmitting feedback signals of the first type, indicating that said portable control means is connected to the lines, manually operable means for selecting decoder control functions, and means for transmitting feedback signals of a second type, to convey the selected decoder control functions; and
an encoder includingmeans for detecting and storing feedback signals of said first and second types, means for selecting for transmission on/off codes from a predetermined sequence of commands, if said portable control means is not connected to the lines, means for selecting for transmission on/off codes determined by said feedback signals of the second type, if said portable control means is connected to the lines, and means for encoding the selected on/off codes and decoder addresses onto the lines for transmission to said decoder and said portable control means. - View Dependent Claims (25, 26, 27)
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28. A method of controlling operations of a plurality of switchable devices in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of decoders, said method comprising the steps of:
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encoding control signals for transmission with an alternating-current power signal along common conducting lines to the decoders, said encoding step including selectively rectifying the power signal and thereby selectively suppressing current flow in one direction to encode the control signals in a binary fashion; decoding the control signals at least one decoder; operating a switchable device at the decoder in accordance with the decoded control signals; and transmitting a feedback signal back to the encoder during a temporary interruption of the power signal, following the receipt of control signals intended for the decoder, to indicate the state of the switchable device at the decoder after said operating step. - View Dependent Claims (29, 30)
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31. For use in a digital control system in which both power and control signals are transmitted along the same conducting lines from an encoder to a plurality of decoders, a method for the control of switchable devices in the system from any desired point along the conducting lines, said method comprising the steps of:
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connecting a portable operator at a desired location along the conducting lines; periodically transmitting from the encoder a control signal addressed specifically to the portable operator; manually selecting a control function at the portable operator; monitoring at the portable operator all control signals transmitted by the encoder; transmitting feedback signals to the encoder, in response to control signals monitored by the portable operator, the feedback signals being indicative of the selected control function; and automatically performing the selected control function at the encoder instead of performing control functions in accordance with a predetermined schedule. - View Dependent Claims (32, 33, 34, 35)
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Specification