WO2002099543A1

WO2002099543A1 - Control system and method

Info

Publication number: WO2002099543A1
Application number: PCT/AU2002/000733
Authority: WO
Inventors: James Dunstone Townsend; Terence Raymond Crawn
Original assignee: Irrigation Control Networks Pty Ltd
Priority date: 2001-06-06
Filing date: 2002-06-06
Publication date: 2002-12-12
Also published as: CA2448633A1; NZ530030A; AUPR547501A0; US20040194833A1

Abstract

The invention relates to a control system and method, particularly for providing sophisticated switching control, such as for the provision of irrigation control and/or scheduling lighting schedules, security measures, and other purposes, with respect to a site or a series of sites in an area. A method of control for a distributed event system is disclosed, the method providing control of events at one or more locations, each location associated with a programmable location controller (10) able to cause or permit a prescribed event to be carried out at that location, each location controller (10) able to receive control commands from a remote controller, each location controller (10) having at least two default settings to govern implementation of said prescribed event in case of non-receipt of commands from said remote controller. The default settings may be automatically selectable in accordance with the time, e.g. time of day, day of week and/or season of year.

Description

Control System and Method

Introduction

This invention relates to a control system and method, particularly for providing sophisticated switching control, such as for the provision of irrigation management and/or scheduling lighting schedules, security measures, and other purposes, with respect to a site or to a series of sites in an area.

Background of the invention

In respect of irrigation control technology, devices to start and stop irrigation cycles without human intervention (generally known, and referred to hereinafter as

'controllers') are well known and are the subject of a number of patents and patent applications. These devices send an electric current (usually 24vAC in horticultural, agricultural or domestic use) to a remote solenoid valve causing that valve to open. Closure of the valve is usually effected by discontinuing the supply of electric current to the solenoid of the valve whereupon the valve is closed, eg by a suitable resilient means. Most controllers are able to accommodate a number of such valves, opening and closing them in a programmed succession for prescribed times on prescribed days of the week. This series of sequential valve opening and closing - for specified times on specified days - is generally referred to as an 'irrigation program'. Some - indeed many - of the known devices are capable of storing and executing more than one such program, thus adding a degree of flexibility to what may be accomplished.

A major failing of such devices is that, in general, they are capable only of repeating the program or programs, without any ability to respond other factors, and particularly to weather conditions, rain etc. As a result of this problem, the operation of the type of irrigation controller described above often results in considerable wastage of water.

Some attempts have been made to tackle this problem of water wastage due to controllers which can only repeat a predetermined schedule. These include:

• rain switches which prevent controller operation during and shortly after rain;

• soil moisture measuring devices which prevent controller operation when soil is judged to be sufficiently moist; and

• controllers which are able to schedule their operations using meteorological data. One of the present inventors has previously taught methods providing a considerable advance on the above-mentioned techniques, as disclosed in PCT patent applications O- 97/27733 and O-99/48354.

In these above-mentioned methods, enabling/disabling or otherwise controlling the activity and/or output of a controller is usually performed by means of a switch relay located in the electrical circuit between the controller and the solenoids of the irrigation supply valves. The switching coil of this relay can be energised and de-energised to control the device in which it is incorporated, in order to achieve the local activity, (or lack thereof) required. Such relays are typically wired to the irrigation sub-system using either normally closed or normally open terminals. If the sub-system is wired to the relay using normally closed terminals, then the activity to be controlled (ie the programmed event) will occur unless a controlling signal is received by the device incorporating the relay. If the sub-system is wired to the relay using normally open terminals, then the activity to be controlled will not occur unless a controlling signal is received by the device incorporating the relay.

The respective modes of relay wiring have respective advantages and disadvantages depending on:

• the particular circumstance of the activity;

• the time of year; and • the day of week.

With this in mind, it is clear that neither wiring configuration will necessarily always provide the most suitable operating mode.

In this specification, where a iocument, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date:

(i) part of common general knowledge; or

(ii) known to be relevant to an attempt to solve any problem with which this specification is concerned.

Summary of the invention According to the invention in one aspect, there is provided a method of control for a distributed event system, providing control of events at one or more locations, each location associated with a programmable location controller able to cause or permit a prescribed event to be carried out at that location, the location controller able to receive control commands from a remote controller, each location controller having at least two default settings to govern implementation of said prescribed event in case of non-receipt of commands from said remote controller. Preferably, said default settings are automatically selectable in accordance with one or more parameters, for example in accordance with time. This may be in accordance with the season of the year and/or the day of the week and/or the time of the day.

In one form of the invention, the distributed event system comprises an irrigation system, and each location controller is operatively connected with at least one electrically operable water valve to control water supply to an area associated with that location, each location controller including an electrical switch relay having two selectable default positions, 'fail-open' and 'fail-closed'.

Control commands received from the remote controller by said location controller may be provided in accordance with monitored meteorological conditions. In a preferred form, the default position for a location controller is established as part of the power connection configuration to the electrical terminals of the at least one electrically operated water valve.

In one embodiment of this form of the invention, the power connection configuration is selectable under software control, the software being remotely programmable from the remote controller to vary the functional relationship between the selection of the default settings and said one or more parameters.

In another form, the power connection configuration is selectable under hardware control, and may include a bi-polar stable relay.

The invention, then, provides a default mode alteration capability for event enabling systems. In the example of an irrigation control system, where locally programmed irrigation regulation can be overridden in accordance with remote signals issued in response to monitored meteorological conditions, the invention provides a preferred failsafe functionality to the system, such that in the absence of receipt of said remote signals by a local irrigation controller (due, for example, to a break in the communications network to the controller), the irrigation event may be enabled or disabled, selectively in accordance with, say, the day of the week, season of the year, etc. Other parameters (beyond time alone) may alternatively or additionally be used to automatically provide the controller default setting, such as locally monitored light levels, temperature, humidity, rainfall, etc. The connection between the remote controller and the location controller may be provided by way of a distributed computer network such as the Internet, and may include wireless data transmission equipment to transmit control commands from the remote controller to the location controller. According to the invention in a further aspect, there is provided a programmable location controller for a distributed event enabling system controlling events at one or more locations, the controller able to cause or permit a prescribed event to be carried out at a respective location, the controller arranged to receive control commands from a remote controller, wherein the controller has at least two default settings to govern implementation of said prescribed event in case of non-receipt of commands from said remote controller.

Preferably, the controller includes means to select said default settings in accordance with one or more parameters, for example in accordance with time. This may be in accordance with the season of the year and/or the day of the week and/or the time of the day.

The controller may be for use with an irrigation system as said distributed event system, the controller operatively connectable with at least one electrically operable water valve to control water supply to an area associated with that location, the controller including an electrical switch relay having two selectable default positions, 'fail-open' and 'fail-closed'. The controller may include a power connection configuration to the electrical terminals of the at least one electrically operated water valve, said configuration providing the means to establish the default position.

For example, the controller may include software to establish said power connection configuration, and may include means to allow remote programming of said software from a remote controller to vary the functional relationship between the selection of the default settings and said one or more parameters.

Alternatively, the controller may include hardware circuitry to provide said power connection configuration, such as a bi-polar stable relay.

According to the invention in a further aspect, there is provide a programmable irrigation system including the above-mentioned programmable location controller and a plurality of electrically operable water valves operatively interconnected therewith in order to control water supply to an area associated with that location.

According to the invention in a further aspect, there is provided a distributed event system including a plurality of controllers as defined above, including means to provide control commands to said location controllers automatically in accordance with monitored meteorological conditions.

Preferably, then, said remote controller is arranged to provide control commands to said location controller automatically in accordance with monitored meteorological conditions (rainfall, temperature, air humidity, etc), and/or in response to manual override commands.

The location controller may provide the irrigation program, the remote control command receiver, and the default setting means, all as part of a single controller unit. Alternatively, the location controller may be provided as a combination of units. For example, the remote control command receiver and the default setting means may be electrically connected to an existing standard onsite irrigation program controller.

Brief Description of the drawings

By way of non-limiting example, the invention will now be described with reference to the accompanying drawings, in which: Figure 1 schematically illustrates the system of the present invention; and

Figures 2a and 2b illustrate default switching positions in accordance with the invention.

Detailed description of the drawings

The embodiment described below enables a plurality of devices to be automatically placed in whichever default operating mode (normally closed or normally open) is required or is appropriate for the particular situation over the course of time.

The invention will be described below with respect to an irrigation system, but it is to be understood that this is merely by way of exemplification, and in no way to be seen as limiting the potential sphere of application of the invention.

Programmable irrigation controllers, to schedule and manage the irrigation of specific areas to be irrigated, such as parks, gardens and sports facilities, without the need for human intervention, are generally known in the art. A single controller can store one or more irrigation programs for a plurality of valves spread over a number of zones associated with that location. The irrigation programs are set as a function of various measured characteristics of the zones to be irrigated, such as the root zone depth, soil texture, etc, the program for a particular valve thus providing an optimum irrigation event for the associated zone.

It is also known to provide a programmed local controlling device which is able to receive command signals in accordance with monitored meteorological conditions, so that the programmed events may be overridden on command. For example, if rain is detected in a particular zone at which an irrigation event is underway, the irrigation event can be discontinued.

The system may be a true distributed system, with a central controller in communication with a great many local controllers carrying out a variety of functions and spread over a large total area, the central controller receiving and processing weather station assets, governing and monitoring the operation of the local controllers, and running modeling and prediction algorithms, with the objective of providing the most beneficial irrigation regime at every zone in the area. In Applicant's Micromet™ system, the system operates over the Internet, which greatly enhances reliability, and the communication with the local controller is accomplished by way of a wireless radio link, the command data received by an appropriate antenna/receiver at the local controller.

The implementation of commands received from the remote controller is achieved by control of the output of the local controller. This is performed by means of one or more switch relays located in the electrical circuit between the controller and the solenoids of the irrigation supply valves (the irrigation sub-system) . The switching coil of a relay is energised and de-energised to control the device with which it is associated, in order to achieve the local activity, (or lack thereof) required. As a general rule, the controllers in a system of this type are set to a 'fail wet' default, meaning that in the absence of a remote override command (due to any unreliability in the remote controller or in the communication system) they are set to provide an irrigation event, because an over- watering of a zone is generally preferred to an under-watering. However, this situation is far from ideal, as will be explained in further detail below.

If the relay within the controlling device is wired into the sub-system using the normally closed terminals of the relay, then unless a signal is received by the device causing the coil to be energised by the device, the wired-in sub-system will be active for that control period (typically, but not necessarily, one day) . This operating mode can be referred to as 'fail active', meaning that the default condition of the sub-system is an active or operating mode. If the relay within the controlling device is wired to the sub-system using the normally open terminals of the relay, then unless a signal is received by the device causing the coil to be energised by the device, the wired-in sub-system will be inactive for that control period (ie, the program stored in the local controller will not operate on the control valves and they will remain closed. This operating mode can be referred to as 'fail inactive', meaning that the default condition of the sub-system is an inactive or non- operating mode.

The following scenario will make the advantages of these contrasting operating modes clear with respect to the primary factors to be considered, ie the circumstances of the system being controlled, the time of year, and the time of day.

Consider that a particular sub-system being controlled by the device incorporating the relay is an irrigation system. This irrigation system is operated by a standard electronic controller of the type typically used to control the irrigation on an irrigated public open space. An example of such an area is a public park within a major city, with irrigated turf areas, managed by a local government authority such as the local council.

The device typically exerts control over operation of the irrigation controller in one of two ways:

1. The relay of the device is wired across the controller's valve common wire so that the electrical circuits to the valve solenoids can be made or broken by the operation of the relay; or

2. The relay of the device is wired across the controller's sensor port such that valve operation is possible given electrical continuity between the terminals of the sensor port.

In either case, if the relay of the device is connected to the controller using the normally closed terminals of the relay, then on any and every day that a signal is not received resulting in an energising of the relay's switching coil, the irrigation controller will apply an irrigation event. If such a signal is not received then the sub-system will be active (the 'fail active' configuration).

Conversely if the relay of the device is connected to the controller using the normally open terminals of the relay, then a signal resulting in an energising of the relay's switching coil, must be received whenever the irrigation controller is to apply an irrigation event. If such a signal is not received then the sub-system will be inactive (the 'fail inactive' configuration) .

It will be readily appreciated that if a signal failure occurs there will be a fundamental difference in the result between the two systems.

In summer, in most circumstances, an occasional additional irrigation is not likely to be especially problematic. However, in winter, it can be a major problem, as it may lead to excessive waterlogging and, should the area under management to be a sports arena, then a game might be washed out, or the irrigation system actually damaged by the operation.

Similarly an occasional unintended irrigation may not be problematic early in the week, but on a Friday or Saturday in particular may conflict with public use of the park. Should the area under management be a sports arena then operation on a Friday, Saturday or Sunday is significantly more likely to conflict with or affect sporting activity.

Therefore a general summary of the advantageous states relating to the operation of a sub-system in irrigated public open space areas may typically be as follows:

To achieve the optimum basic operating modes as summarised and defined above, sites would have to be continually visited and undergo wiring modification in order to alternately wire the connections between the relay within the device and the sub-system using respectively, the normally open or the normally closed terminals, as required having regard to the time of the year and the day of the week.

In particular, as indicated above, the 'fail inactive' state on Friday and Saturday evenings in summer is especially important in the context of sports turf surfaces, as explained above.

The invention provides a method and system for achieving this conveniently, without requiring site visits or disconnection/reconnection of wiring systems.

With reference to Figure 1, the onsite components of a system in accordance with the invention include a programmable irrigation controller 10, a wireless receiver unit 20, and five electrical solenoids VI -V5 controlling respective irrigation valves in that local area. Unit 20 may be incorporated into controller 10, or may (as illustrated) be a separate unit, 'retrofitted' to a conventional irrigation sub-system.

Controller 10 includes a power source (not shown), a transformer T, a power bus 11, and five independent switch devices 12 managed by a central programmable controller processor (not shown). Controller 10 also provides a common connection C connecting to a common bus for solenoids VI -V5. Each solenoid is wired to a respective switch device 12, and the controller program is thus able to control the timed switching of each valve solenoid, by selective connection of the lines to respective solenoid valves with power bus 11. Unit 20 is wired into common line C as shown in Figure 1, and thus provides an override for the output of controller 10. Unit 20 includes an antenna 21, which provides a signal input to a receiver/processor 22, which controls a relay switching module 23 in accordance with the received signals. Applicant's Micromet™ irrigation device works in this way, receiving remote command signals from a central Micromet computer. Two possible configurations of switching module 23 are shown in Figures 2a and 2b, respectively 'fail active' and 'fail inactive'. In 'fail active' mode, the relay coil 24 is normally energised due to electronic switch 25 being closed, and common connection C is thus normally unbroken. Signals received at receiver 22 result in an opening of electronic switch 25, a resultant de-energising of coil 24, and a breaking of common connection C. With this wiring configuration, in the absence of a received signal, the irrigation program in controller 10 is carried out. In 'fail inactive' mode, the opposite outcome is achieved. In the absence of a received signal, electronic switch 25 is open, coil 24 is unenergised, and common connection C remains open. With this wiring configuration, in the absence of a received signal, the output of controller 10 is not carried out at the irrigation valves.

This desirable result can be achieved by either a software or a hardware solution.

In the software solution, relay 23 in the device defaults to one of two modes. In programming this software device, an instruction set is provided to set switch 25, in order to control how the device will function, and thus whether it is to fail inactive or active, in a time dependent manner. Additional instruction to control the position of switch 25, and thus define the default position of relay 23 (ie whether it is to fail active or inactive at any given time) can be provided from time to time if required, as part of the remote commands issued by the remote controller. In other words, the locally stored time- dependent default mode setting program can be updated from time to time in response to commands received from the remote controller.

In one example of a hardware solution, relay 23 is provided by way of a bi-polar stable relay. The circuitry changing the wiring configuration from normally closed to normally open is connected to appropriate terminals of the bi-polar stable relay. Instruction as to whether it is to fail active or inactive can be sent from the remote controller from time to time as required, causing the bi-polar stable relay 23 to change state.

While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

The invention has been described with reference to an irrigation system, but it is to be understood that it is capable of application in many other spheres. For example, it may be used in controlled distributed lighting systems, or in controlled security applications such as door and gate locking systems.

The word 'comprising' and forms of the word 'comprising' as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions. Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Claims

1. A method of control for a distributed event system, providing control of events at one or more locations, each location associated with a programmable location controller able to cause or permit a prescribed event to be carried out at that location, the location controller able to receive control commands from a remote controller, each location controller having at least two default settings to govern implementation of said prescribed event in case of non-receipt of commands from said remote controller.

2. A method according to claim 1, wherein said default settings are automatically selectable in accordance with one or more parameters, for example in accordance with time.

3- A method according to claim 2, wherein the selection of the location controller default setting is made in accordance with the season of the year and/or the day of the week and/or the time of the day.

4. A method according to any preceding claim, wherein the distributed event system comprises an irrigation system, and each location controller is operatively connected with at least one electrically operable water valve to control water supply to an area associated with that location, each location controller including an electrical switch relay having two selectable default positions, 'fail-open' and 'fail-closed'.

5. A method according to claim 4, wherein control commands received from the remote controller by said location controller are provided in accordance with monitored meteorological conditions.

6. A method according to claim 4 or 5, wherein the default position for a location controller is established as part of the power connection configuration to the electrical terminals of the at least one electrically operated water valve.

7. A method according to claim 6, the power connection configuration being selected under software control, the software being remotely programmable from the remote controller to vary the functional relationship between the selection of the default settings and said one or more parameters.

8. A method according to claim 6, the power connection configuration being selected under hardware control.

9. A method according to claim 8, the power connection configuration including a bipolar stable relay.

10. A programmable location controller for a distributed event enabling system controlling events at one or more locations, the controller able to cause or permit a prescribed event to be carried out at a respective location, the controller arranged to receive control commands from a remote controller, wherein the controller has at least two default settings to govern implementation of said prescribed event in case of non- receipt of commands from said remote controller.

11. A controller according to claim 10, including means to select said default settings in accordance with one or more parameters, for example in accordance with time.

12. A controller according to claim 11, including means to select the location controller default setting in accordance with the season of the year and/or the day of the week and/or the time of the day.

13- A controller according to one of claims 10 to 12 for use with an irrigation system as said distributed event system, the controller operatively connectable with at least one electrically operable water valve to control water supply to an area associated with that location, the controller including an electrical switch relay having two selectable default positions, 'fail-open' and 'fail-closed'.

14. A controller according to claim 13, including a power connection configuration to the electrical terminals of the at least one electrically operated water valve which configuration provides the means to establish the default position.

15. A controller according to claim 14, including software to establish said power connection configuration, and including means to allow remote programming of said software from a remote controller to vary the functional relationship between the selection of the default settings and said one or more parameters.

16. A controller according to claim 14, including hardware circuitry to provide said power connection configuration.

17. A controller according to claim 16, said circuitry including a bi-polar stable relay.

18. A programmable irrigation system including the programmable location controller of any one of claims 13 to 17 and a plurality of electrically operable water valves operatively interconnected therewith in order to control water supply to an area associated with that location.

19- A distributed event system including a plurality of controllers according to any one of claims 13 to 17, including means to provide control commands to said location controllers automatically in accordance with monitored meteorological conditions.