Data processing: generic control systems or specific application – Specific application – apparatus or process – Mechanical control system
Reexamination Certificate
2000-11-22
2004-07-20
Rodriguez, Paul (Department: 2125)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Mechanical control system
C700S019000, C137S078200, C137S624110, C239S069000, C340S315000
Reexamination Certificate
active
06766221
ABSTRACT:
BACKGROUND OF THE INVENTION
This particular invention relates generally to a two-wire controlling and monitoring system particularly for irrigation of localized areas of soil.
DESCRIPTION OF THE RELATED ART
The most commonly known two-wire irrigation control systems, such as control systems disclosed in U.S. Pat. Nos. 4,007,458 and 4,176,395 hereby incorporated by reference, provide control of a number of remotely located irrigation or sprinkler valves from a central location by means of control signals encoded on to a single pair of power transmission lines linking a central encoder and a number of remote decoders.
The two-wire irrigation control system according to U.S. Pat. No. 4,007,458 encodes and transmits an address of a specific remotely located irrigation valve and on/off signals onto an alternating current signal (AC) by clipping half portions of the signal to represent zero values.
Similarly the two-wire interactive irrigation control system according to U.S. Pat. No. 4,176,395 transmits data by selectively clipping the original power frequency signal during eight consecutive cycles, suppressing the power frequency signal during the following full cycle, during which time a feedback signal may be transmitted from sensors located at specific areas, then transmitting eight undistorted power frequency cycles, and suppressing the power frequency signal for one following cycle, during which time a feedback signal relating to a portable operator may be transmitted.
Both two-wire irrigation control systems according to U.S. Pat. Nos. 4,007,458 and 4,176,395 communicate to remotely located irrigation valves or decoders by clipping of the power signals consequently while performing a transmission on the power line power to the remotely located irrigation valves or decoders is significantly reduced.
Furthermore the two-wire irrigation control systems according to U.S. Pat. Nos. 4,007,458 and 4,176,395 utilizes sinusoidal signals for transmitting power to remotely located irrigation valves or decoders. Sinusoidal signals being AC signals generally need to be converted into DC in order to drive microprocessor electronic circuitry adding total costs of the two-wire irrigation systems for the electronics incorporated in the remotely located irrigation valves or decoders.
An object of the present invention is to provide a two-wire controlling and monitoring system for in particular controlling a plurality of controllable irrigation or sprinkler valves placed at specific localized areas, monitoring specific irrigation parameters at the specific localized areas and communicating through a two-wire cable with line and sensor decoders located at the specific localized areas while limiting above described power loss due to signalling on the-two-wire cable.
A particular advantage of the present invention is utilization of a power supply signal for the operation of the controllable irrigation valves hence performing an improved power transmission within general safety specifications.
A particular feature of the present invention is an improved corrosion resistance.
The above object, the above advantage and the above feature together with numerous other objects, advantages and features which will be evident from the below detailed description of a preferred embodiment of the present invention is according to a first aspect of the present invention obtained by a two-wire controlling and monitoring system for in particular irrigation of localized areas of soil and comprising:
a water pipeline providing water to said localized areas of soil,
a first plurality of controllable irrigation valves each positioned at a specific area of said localized areas of soil, communicating with said water pipeline, providing watering or non-watering of said specific area of said localized areas of soil and having a pair of valve control inputs,
a second plurality of field sensors positioned at specific areas of said localized areas of soil, providing specific irrigation parameters and having a pair of sensor outputs,
a third plurality of localized irrigation control units each comprising a sensor decoder having a pair of sensor inputs connected to said pair of sensor outputs of a specific field sensor of said second plurality of field sensors for providing power to said second plurality of field sensors and recording said specific irrigation parameters from said second plurality of field sensors and/or a line decoder having a pair of valve control outputs connected to said pair of valve control inputs of a specific controllable irrigation valve of said first plurality of controllable irrigation valves for providing valve control signals to said first plurality of controllable irrigation valves, said sensor decoder and said line decoder further each having a pair of control and power supply inputs,
a controller and power supply unit having a set of schedules of instructions and having a pair of control and power outputs supplying power by applying a first alternating DC voltage signal defining a voltage maximum having a first pulse width and defining a voltage minimum having a second pulse width to one of said pair of control and power outputs, simultaneously applying a second alternating DC voltage signal similarly shaped but of inverted polarity as compared to said first alternating DC voltage signal to another of said pair of control and power outputs and applying an alternating DC current defining a current maximum having a third pulse width and defining a current minimum having a fourth pulse width to said pair of control and power outputs,
a two-wire cable interconnecting said controller and power supply unit and said third plurality of localized irrigation control units and connecting said pair of control and power outputs of said controller and power supply unit to said control and power inputs of said third plurality of localized irrigation control units and providing said power from said controller and power supply unit to each of said third plurality of localized irrigation control units, and
said controller and power supply unit transmitting said schedules of instructions to said third plurality of localized irrigation control units through said two-wire cable and receiving said specific irrigation parameters from said third plurality of localized irrigation control units through said two-wire cable.
According to the basic realization of the first aspect of the present invention the application of two alternating DC voltage signals having respectively inverted polarity on to the two-wire cable provides an improved power transmission with respect to prior art's application of sinusoidal voltage signals. The improvement is approximately by a factor of 2. Sinusoidal voltage signals although ideal for some purposes impose a restriction on maximum attainable power transmission during a time frame caused by the inherent shape of the voltage signal squared as compared to a square wave voltage signal squared. Furthermore, by relying on slow alternating DC voltage signals for powering of the decoders instead of relying on sinusoidal voltage signals having standard 50 Hz or 60 Hz network frequencies a less noise sensitive and subsequently cheaper circuit may be implemented, since relatively little attention should be given to noise considerations. Additionally, the square wave structure of the alternating DC voltage signal provides an ideal platform for carrying binary information, which will be further described below.
The water pipeline characteristic of the two-wire irrigation controlling and monitoring system according to the first aspect of the present invention is wholly or partly buried under ground, or the water pipeline is placed on the ground. Parts of the pipelines being above ground level provide movable sections that may easily be moved into positions according to the conditions of the local areas. Furthermore the water pipeline is constructed from plastic materials or metal materials such as iron, steel, copper, silver, gold or any alloys thereof in any combinations thereof. Generally pl
Klein Howard J.
Klein O'Neill & Singh, LLP
Rodriguez Paul
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