Patent Application
20170265403
The present invention relates to irrigation systems in which various irrigation zones are controlled through pressure pulse signals communicated through the irrigation water in the conduits of the irrigation system. More particularly, the invention includes methods and apparatus for facilitating the desired pressure pulse-based communications in the system.
Modern irrigation systems, particularly those used in residential settings, commonly include a network of distribution conduits including a number of separately controlled irrigation zones. The network of distribution conduits is connected to a supply conduit that supplies irrigation under suitable pressure, and a master valve is used to control the water supply from the supply conduit. Each irrigation zone includes a zone valve which is opened to allow irrigation in the respective zone, and then closed while another irrigation zone is operating. An irrigation controller is typically included in the irrigation system to open and close both the master valve and zone valves as needed according to an irrigation schedule. In particular, the irrigation controller controls the master valve to open simultaneously with a first zone valve in a sequence of zone valves to be operated for a given irrigation program, and then closes the master valve at the end of the sequence.
In order to control the master valve and zone valves, the irrigation controller must be able to send to the respective valve a signal which either operates the valve or triggers another signal to operate the valve. Perhaps the most common arrangement currently used for residential irrigation systems is an arrangement in which the irrigation controller sends operating signals to the master valve and each zone valve through a respective electrical wire which runs from a terminal of the irrigation controller to the respective valve. The operating signals are at a suitable voltage to operate the respective zone or master valve, which is commonly a solenoid-operated valve.
The electrical wires which run to the various remote valves in this common arrangement represent a weak link in the system for a number of reasons. First there is the added cost of the electrical wires and the cost of installing the wires. Additionally, the wires are subject to damage during yard work. The wires and connections to the wires are also subject to corrosion since they are exposed to a relatively harsh outdoor and underground environment.
In order to address some of the problems with having to run electrical wires in an irrigation system, irrigation systems have been proposed which eliminate the need for such wires. In particular, U.S. Pat. No. 7,383,721 discloses an irrigation system in which the remote zone valves are controlled through communications encoded in pressure pulses applied to the irrigation water in the network of irrigation conduits. The pressure pulses in this proposed system are detected and interpreted by a signal receiving arrangement associated with the remote valve, and the receiving arrangement then produces a suitable operating signal to open or close the valve accordingly. Although this pressure pulse communication arrangement for controlling the zone valves in an irrigation system eliminates the need for electrical wires to the zone valves, the arrangement raises a number of other issues which have ultimately prevented the wide-spread adoption of such systems. The present invention is directed to some of those problems, especially the problem of ensuring reliable pressure pulse-encoded communications to the remote zone valves.
The present invention provides a control unit that ensures the irrigation conduits in a pressure pulse communication-based irrigation system are ready for receiving the desired pressure pulse signals necessary for communicating control instructions for the remote zone valves. The invention also encompasses master/pulser devices incorporating such a control unit and further encompasses methods for operating an irrigation system relying on pressure pulse-based communications to the zone valves.
A control unit according to one aspect of the present invention includes a communication output terminal associated with a communication signal circuit, and a supply output terminal associated with a supply signal circuit. The communication signal circuit operates to apply a communication drive signal to the communication output terminal in response to a communication control signal, while the supply signal circuit operates to apply a supply operating signal to the supply output terminal in response to a supply control signal. The control unit according to this aspect of the invention further includes a controller such as a suitable microcontroller which operates to direct the supply control signal to the supply control circuit with a particular timing relative to directing the communication control signal to the communication signal circuit. More specifically, the controller directs the supply control signal to the supply signal circuit at a first point in time and then directs the communication control signal to the communication signal circuit after a communication condition is met in the network of irrigation conduits after the first point in time. The communication condition is selected to generally ensure that the supply valve is opened to the network of irrigation conduits for a sufficient period of time prior to a pressure-pulse communication attempt so that the conduits are full of irrigation water and in condition to transmit the desired pressure pulse-encoded information to the zone valves. Thus, for example, in the event irrigation water has leaked or otherwise drained from the network of irrigation conduits since a zone valve in the system was last operated, the control unit according to the invention causes the irrigation conduits to be refilled so that the desired pressure pulses may be communicated to the zone valves when desired.
Another aspect of the invention encompasses a master/pulser unit which incorporates the control unit as described above. Such a master/pluser unit may include in addition to the control unit, a flow path (defined by a suitable conduit) having a supply end adapted to receive irrigation water from a supply conduit and having a distribution end adapted to be connected to the network of irrigation conduits. An electrically operated supply valve is connected in the flow path, along with a branch conduit preferably connected between the supply valve and the distribution end. An electrically operated pulser valve is connected in the branch conduit in position to selectively open and close the branch conduit to the atmosphere. In this aspect of the invention, the supply terminal of the control unit is connected to the supply valve, and the communication output terminal is connected to the pulser valve. When the master/pulser unit is connected for operation with a network of irrigation conduits, the supply valve in the unit is responsible for controlling the supply of water to the system and the pulser valve is used to generate the pressure pulses for communications to the various zone valves and their associated receiving arrangement.
In the above description of the master/pulser unit, various elements are described as being “connected” to another element. For example, the preceding paragraph describes the master valve as being “connected” in the flow path. The term “connected” in this example and elsewhere in this disclosure and the accompanying claims means “operatively connected” so that the device may perform its stated function. Thus the supply valve is connected in the flow path so that the valve blocks flow through the flow path when the valve is closed, and allows flow through the flow path when the valve is open. As a further example, the above description that the supply terminal of the control unit is “connected” to the supply valve means that the terminal is connected via a suitable control wire to the electrically operated supply valve so that an electrical operating signal may be applied to a terminal of the supply valve to open and close the valve.
As noted above, the control unit sends the communication control signal to the communication signal circuit after a communication condition is met in the network of irrigation conduits. Any of a number of different conditions may be selected as the communication condition to ensure the irrigation conduits are in the desired condition for communicating pressure pulse-encoded signals. In one embodiment of a control unit according to the present invention, the communication condition comprises a predetermined amount of time after the first point in time. In this embodiment the control unit may employ a suitable timing arrangement to recognize when the predetermined amount of time has elapsed after the supply valve has been opened.
In other embodiments the communication condition may be identified by a measurable parameter of the network of irrigation conduits. The control unit in these embodiments may include a sensor input terminal connected to a sensor input of the controller. The controller in this case operates to determine whether the communication condition is met based on a sensor input signal received at the sensor input terminal. For example, the communication condition may comprise a predetermined flow rate and the sensor input signal is indicative of flow rate into the network of irrigation conduits. In this example the master/pulser unit may include a network condition sensor comprising a flow rate sensor. When the supply valve is opened by the control unit in these embodiments of the invention, the flow rate sensor will initially indicate a flow of irrigation water into the network of irrigation conduits in the event that irrigation water has drained from the conduits over a period of inactivity. Because all of the zone valves in the system are closed at this point, this initial flow will cease once the conduits leading to the zone valves fill with irrigation water. This cessation of flow into the network of irrigation conduits indicates the conduits are full and thus may be taken as an indication that the communication condition has been met.
Alternatively, the communication condition may comprise a predetermined pressure and the sensor input signal is indicative of pressure in the network of irrigation conduits. In this latter example, the master/pulser unit may include a network condition sensor comprising a pressure sensor connected at a suitable point to sense the pressure in the network of irrigation conduits. When the supply valve is opened by the control unit in this alternative embodiment, the pressure in the network of irrigation conduits will initially be below the supply line pressure assuming water has previously drained from the irrigation conduits. The pressure in the irrigation conduits will increase to the supply line pressure as the irrigation conduits fill with irrigation water from the supply line, and thus a pressure at or near the supply line pressure indicates the conduits are full and ready for pressure pulsed-based communications.
Another aspect of the invention includes a method for controlling an irrigation system which employs pressure pulse-based communications to zone valves. A method according to this aspect of the invention includes receiving a communication preparation signal which may be a signal generated at a suitable point in time before a zone of the irrigation system is to be activated. In response to the communication preparation signal, the method includes generating a supply control signal which is used to open the supply valve such as the supply valve described above in connection with the master/pulser unit. The method then includes determining if a communication-ready condition is present in the network of irrigation conduits, and in response to the communication-ready condition, applying a communication release signal to enable a communications to an electrically operated pulser valve in the irrigation system such as the above-described pulser valve.
These and other advantages and features of the invention will be apparent from the following description of illustrative embodiments, considered along with the accompanying drawings.
Referring to
It should be noted here that although the present invention is directed to apparatus and methods used with pressure pulse-based communications in irrigation systems, the various aspects of the invention are independent of the particular pressure pulse encoding used in the system. Thus, details of the pressure pulse generation, encoding, detection, and interpretation are not necessary for an understanding of the present invention. Such details are therefore omitted from this disclosure so as not to obscure the invention in unnecessary detail.
Referring to
In the illustrated example control unit shown in
Microcontroller 301 may comprise any controller suitable for performing the process described more fully below with reference to
The operation of control unit 214 may now be described with reference to the flow chart of
Regardless of the specific nature of the communication preparation signal or under what circumstances it is generated by microcontroller 301, the illustrated example process according to the invention responds to that signal by applying a control signal to the supply signal circuit 316 as indicated at process block 402 in
Once supply valve 205 has been opened in response to the signal applied as indicated at process block 402, the process includes checking for a communication condition (“COM CONDITION”) in the network 100 of irrigation conduits. This inquiry is shown at process block 404 in
As noted above, the communication condition may be defined as a certain amount of time which has elapsed since the supply valve is opened (at process block 402). In this case the inquiry at 404 in
The process shown in
As used herein, whether in the above description or the following claims, the terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, that is, to mean including but not limited to. Any use of ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another, or the temporal order in which acts of a method are performed. Rather, unless specifically stated otherwise, such ordinal terms are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term).
The term “each” may be used in the following claims for convenience in describing characteristics or features of multiple elements, and any such use of the term “each” is in the inclusive sense unless specifically stated otherwise. For example, if a claim defines two or more elements as “each” having a characteristic or feature, the use of the term “each” is not intended to exclude from the claim scope a situation having a third one of the elements which does not have the defined characteristic or feature.
The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the present invention.
