STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the Provisional specification filed in relation to New Zealand Patent Application Number 620435, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to improvements in and relating to the control of automated electrical devices. The present invention has particular application in the control of automated electrical devices during fault conditions.

BACKGROUND ART

Automated systems such as automatic pumps and compressors are commonly used, among other functions, to maintain a resource in a ready state. In terms of pumps this resource may be a particular level, or head, of water in a water tank. A compressor may maintain an air cylinder above a certain pressure, or may operate a refrigeration, or air-conditioning unit, to maintain a particular temperature in a cool room.

Automated systems typically operate in response to a sensor that monitors the resource provided by the automated system. If the resource is below a desired level then the automated system is activated in order to increase the available resource to above a particular level, at which time the automated system deactivates.

As an example, a water pump supplying a water tank will detect the level of water in the tank by way of sensor, such as a float switch or the like. As water is consumed from the tank the water level reduces, resulting in the float switch activating the pump. Once water level rises above a desired level, due to water being pumped into the tank, the float switch deactivates the pump. One problem that can arise occurs if the tank is ruptured, or a feed from the tank, such as a water supply pipe, is broken. In such a case the tank may empty and the float switch permanently activates the pump. If the fault is not observed immediately a large volume of water may be pumped causing flooding, damage to plant or erosion. In some cases it may be damaging for the pump to operate continuously for a long period of time. In the example of a compressor on a refrigeration unit the same situation may be created if, for example, someone leaves a door to the refrigeration unit open. Because the refrigeration unit is no longer sealed the compressor attempts to cool a much larger volume. This results in the compressor running continuously, or for much longer periods of time than normal. Abnormal running results in wear on the compressor components as well as excess power consumption.

It would therefore be useful to be provided with a system that simply and easily attaches to and functions with an automated system to prevent abnormal operation. It would also be useful for such a system to be simple to attach to an existing automated system without the need for expertise, such as an electrician or the like.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION

The present invention relates to a monitoring system for timing the duration of activity of an automated system and, if the active time exceeds a predefined time period, disconnecting the supply of power to the automated system. One non-limiting example of how the system may be used is in conjunction with a float switch activated water pump supplying a water tank. In use, as water is consumed from the water tank the float switch trips and engages the pump to supply water to the tank. Once the water level in the tank is restored the float switch deactivates the pump. However, if the tank has been ruptured, or the float switch has failed, or water is being consumed from the tank at a continuous and/or excessive rate, the pump will be activated for a longer period than it would under normal conditions. In such an event the monitoring system of the present application disconnects power to the pump thereby stopping the supply of water to the tank.

For the purposes of the present invention activity should be understood to mean the active function of the device, e.g. a fan blowing air, a compressor compressing gas or a pump pumping a fluid. Similarly a non-active state should be understood to mean a standby mode whereby the device is ready to enter its active state. Typically switching between an active and standby mode will be initiated by a sensor detecting a particular condition.

It should be appreciated that the invention may be used for any electrically supplied autonomous device that has a definable normal/maximum on-time. Examples of such autonomous device may include, but should not be limited to, compressors, lights, fans, generators, motors or the like.

According to one aspect of the present invention there is provided a monitoring and control system, including:

• a power input; · a power output;

• a switching unit electrically connected between the power input and the power output, the switching unit configured to provide: o a default on position wherein a current path is provided from the power input to the power output, and o an off position wherein no current path is provided from the power input to the power output;

• a power consumption detector configured to detect the consumption of power from the power output;

• a timing unit; and · a controller; wherein the timing unit is configured to measure the period of time that the power consumption detector detects power as being consumed from the power output, and wherein the controller is configured to switch the switching unit between the default on position and the off position once a predetermined time has been measured by the timing unit. In preferred embodiments the timing unit includes a countdown timer. The countdown timer may be implemented in a number of ways. Preferably a microprocessor will provide the countdown function. However it will be appreciated that other means of timer may be used without departing from the scope of the present invention. For example a bimetallic switch or mechanical timer or the like may be used. Preferably the countdown timer resets each time the power output is detected as switching from not supplying power to supplying power. In embodiments that make use of a microprocessor resetting the countdown timer is performed by returning a timing count to a start count. For mechanical timers an automatic mechanical reset may typically be employed which resets the timer. Bi-metallic timers provide self-reset by way of convection/radiative cooling. Typically an automated system, such as a pump or compressor, will operate on a periodic, semi periodic or even random basis. Regardless of the frequency with which a particular automated system activates under normal use, the duration of each cycle will generally be known by an installer, or may be obtained by empirical observation. By adjusting the countdown timer to a period greater than the maximum observed, or normal, cycle time the monitoring system of the present invention may be configured to de-activate the automated system when an abnormally long cycle is detected.

In some embodiments the countdown timer includes a cycle timer.

Typically the cycle timer will be configured to reset the countdown timer once the current active cycle has stopped and a pre-determined time period has passed. The purpose of the cycle timer is to capture fault conditions in which an automated system enters a state of continuously toggling between active and inactive modes of operation. It will be appreciated that a cycle timer may be implemented independently of the countdown timer, therefore the exact manner in which the cycle timer is implemented should not be seen as being limiting.

In preferred embodiments the predetermined time is configurable. A configurable predetermined time allows the monitoring system to be configured for a particular automated system attached to the power output. For example, a water pump may have a typical cycle time of between 10 and 15 minutes and a maximum cycle time of 30 minutes. In this example the predetermined time may be set to 35 minutes to accommodate the worst case cycle time. If the water pump runs for greater than 35 minutes it is likely that either the pump is defective, or the fluid being supplied by the pump is not being used within the expected parameters. A further example of the system may be an air compressor having a cycle time of 1 to 5 minutes with a maximum cycle time of 5 minutes. In this example the predetermined time may be set to anything greater than 5 minutes.

In preferred embodiments the predetermined time may be configurable to a resolution of seconds, minutes or hours. In some preferred embodiments the predetermined time may be configurable in steps of 15 minutes.

In preferred embodiments the power consumption detector is in the form of one or more discrete electronic components. The detection of power consumption is typically performed by way of detection of current consumption, voltage drop, or the like. Detection and measurement of power consumption is well known in the art of electronic and electrical circuit design, therefore the manner in which power consumption is measured/detected should not be seen as limiting.

In preferred embodiments the power consumption detector includes a low power consumption threshold and an active power consumption threshold. The low power threshold will typically be configured to be greater than the power consumed by an automated device when in its inactive state when connected to the output of the monitoring system. The active power consumption threshold will typically be configured to be less than the power consumed by the automated device when in its active state when connected to the output of the monitoring system. In preferred embodiments the power consumption detector has an adjustable low power consumption threshold.

In preferred embodiments the power consumption detector has an adjustable active power consumption threshold.

It will be appreciated by the skilled person that some devices that may be supplied by the monitoring system may consume power at a continuous, random or periodic reduced power level in between periods of more elevated power consumption when in their active state. An adjustable threshold allows the monitoring system to only operate the timer during the periods of elevated power consumption.

In some embodiments the low power consumption threshold and the active power consumption threshold may be the same.

In preferred embodiments the power consumption detector includes a current detector configured to measure the current being supplied to the load from the power output.

In preferred embodiments the current detector is monitored by the, or a, controller.

In preferred embodiments the controller is configured to measure the peak current consumed by the automated system attached to the power output.

In preferred embodiments the measured peak current is compared to a maximum current limit by the controller and if the maximum current limit is exceeded the controller switches the switching unit from the default on position to the off position. In preferred embodiments the maximum current limit is adjustable.

The physical switching component contained within the switching unit may take a number of forms, examples of which include, but should not be seen as being limited to, solid state devices such as transistors, SCRs, triacs or the like, or mechanical switches such as electromechanical relays or the like.

In preferred embodiments the switching unit is a relay.

In preferred embodiments the switching unit includes a latching function whereby the switching unit requires resetting prior to switching from the off position back to the default on position.

In some embodiments resetting of the switching unit is performed manually. Manual resetting may take any number of forms without departing from the scope of the present invention. Non limiting examples of potential mechanisms for providing manual resetting may include: disconnection of power from the power input; a manually operable switch; a remotely operable user interface; or the like.

In preferred embodiments the switching unit is automatically reset. Automatic resetting may be performed in a number of ways, one non limiting example being a reset timer which periodically resets the switching unit.

It will be appreciated that the controller may be of a distributed architecture whereby different elements of control are afforded to separate controllers. These controllers may be further microprocessors, or they may be one or more discrete electronic or mechanical components. In preferred embodiments the controller includes one or more suitably programmed

microprocessors.

In preferred embodiments the monitoring system includes a user interface.

The term user interface should be understood to include within its scope visual, audible and tactile feedback systems. It should also be appreciated that the user interface may be remote to the monitoring system. Examples of remote interfaces include, but should not be limited to, cellular devices, control panels and/or computer terminals. It will be appreciated that embodiments of the monitoring system that interact with remote user interfaces such as cellular or networked devices will include a communication module configured to communicate one or more parameters associated with the monitoring system to the remote interface device. In preferred embodiments the user interface is configured to communicate one or more parameters associated with the monitoring system to the remote interface device.

In preferred embodiments the user interface is configured to communicate one or more of: the presence of power at the power input;

• the detection of the consumption of power from the power output;

• the state of the switching unit; and/or

• whether the switching unit has changed state. In some preferred embodiments the user interface includes one or more visual indicators physically associated with the monitoring system.

In preferred embodiments the one or more visual indicators include LEDs.

In preferred embodiments the monitoring system is housed within at least an IP 44 rated casing. Some embodiments may include a housing with an IP56 rating. It will be appreciated that the IP rating of the housing may vary depending upon the environment in which the monitoring system is to operate. For example, an installation in a remote location may require a higher IP rating than an installation in a modern building.

In some preferred embodiments the monitoring system includes one or more surge

suppression components. In one preferred embodiment the power input is a mains input supply socket.

In another preferred embodiment the power input is a power supply cord.

In one preferred embodiment the power output is a mains output socket.

In another preferred embodiment the power output is a power supply cord.

According to a second aspect of the present invention there is provided a method of using a monitoring system to deactivate an automated system, the monitoring system including a power input electrically connected to a power output by a switching unit; a power consumption detector configured to detect the consumption of power from the power output; a timing unit configured to measure the period of time that the power consumption detector detects power as being consumed from the power output and a controller configured to switch the switching unit between a default on position wherein a current path is provided from the power input to the power output and an off position wherein no current path is provided from the power input to the power output, the method including the steps of: a) supplying power to the power input; b) supplying power to the automated system by way of the power output; c) detecting whether power is being consumed by the automated system; d) measuring the period of time that power has been consumed by the automated system; and e) switching the switching unit from the on position to the off position if the period of time that the automated system has been consuming power exceeds a pre-defined period of time.

According to a further aspect of the present invention there is provided a method of using a monitoring system to prevent a water tank from running dry, the monitoring system including a power input electrically connected to a power output by a switching unit; a power consumption detector configured to detect the consumption of power from the power output; a timing unit configured to measure the period of time that the power consumption detector detects power as being consumed from the power output and a controller configured to switch the switching unit between a default on position wherein a current path is provided from the power input to the power output and an off position wherein no current path is provided from the power input to the power output, the method including the steps of: a) supplying power to the power input; b) connecting a water pump supplying water to the water tank to the power output; c) detecting whether power is being consumed by the water pump; d) measuring the period of time that power has been consumed by the water pump; and e) switching the switching unit from the on position to the off position if the period of time that the water pump has been consuming power exceeds a pre-defined period of time.

In preferred embodiments the method includes the step of resetting the timing unit when the power output is detected as changing from not supplying any power to supplying power.

In preferred embodiments the step of resetting the timing unit is only performed once a cycle timer has lapsed.

In preferred embodiments the detecting step includes detecting whether the power being consumed is below a low power consumption threshold.

In preferred embodiments the detecting step includes detecting whether the power being consumed is above an active power consumption threshold.

In preferred embodiments the method includes the step of: f) comparing a measured current being supplied from the output to a maximum current limit and if the maximum current limit is exceeded the controller switching the switching unit from the default on position to the off position. Preferred embodiments of the present invention may provide a number of advantages over the prior art, non-limiting examples of which may include:

• providing a system that functions with an automated system to prevent abnormal

operation; and providing a system that is easy to connect to an automated system with little to expertise required.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of a first system for dosing plants in accordance with one preferred embodiment of the present invention;

Figure 2 shows a perspective view of a second system for dosing plants in accordance with one preferred embodiment of the present invention;

Figure 3 shows a perspective view of a third system for dosing plants in accordance with one preferred embodiment of the present invention; and

Figure 4 shows a perspective view of a lighting module in accordance with one preferred embodiment of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

With reference to Figures 1 a and 1 b there is shown a monitoring and control system for timing the duration of activity of an automated system, shown in Figure 2, the monitoring system as generally indicated by designator 1. The monitoring and control system 1 includes a power input 2 which is in the form of a socket into which a supply cord, shown in Figure 2, can be plugged. Alternate embodiments may have a power input 2 in the form of a power cord integral to the monitoring and control system 1. An integrated cord may be useful if a higher ingress protection (IP) rating is desired. In yet further alternative embodiments power input 2 may be prongs formed integrally with the housing of the monitoring and control system 1 configured for plugging directly into a mains socket. The power supplied to the device may be provided in a number of ways, examples of which include but should not be limited to, grid power, a generator, batteries, solar arrays or the like, none of which are shown.

A power output 4 is electrically connected to the power input 2 by way of a switching unit 5. The switching unit 5 may take a number of forms, non-limiting examples of which include solid state devices such as transistors, or mechanical devices such as relays or solenoid switches or a combination thereof. Switching unit 5 provides a default on position, shown in Figure 1 a, wherein a current path 6 is provided from the power input 2 to the power output 4. Controller 7 includes one or more electronic components and is configured to drive the switching unit 6 from the default on position to an off position, shown in Figure 1 b, in which no current path is provided between the power input 2 and the power output 4. The configuration of the one or more electronic components will vary depending on the type of switching unit 5, as such the exact configuration is not considered pertinent to the working of the present invention as such configuration would be well known to a person skilled in the art.

Controller 7 monitors power consumption detector 9 which takes the form of a current transformer. By measuring the voltage developed across the current transformers secondary sense windings the controller 7 can determine the amount of power that is being consumed from the power output 4. The power consumption detector 9 will typically include a current sensing circuit in addition to the current transformer. The current sensing circuit being configured to provide a signal representative of the current being consumed from the output 4 and which is measurable by a microprocessor or the like. In some embodiments the power consumption detector may simply be a current transformer and a sense resistor, the detection circuitry associated with measuring the current through the current transformer being incorporated into the controller 7.

Timing unit 10 is configured to measure the period of time that the power consumption detector 9 detects power as being consumed from the power output 2. The Controller 7 will typically include a microprocessor and as such the timing unit 10 may be integrated into the controller 7 microprocessor. In some embodiments a microprocessor may not be used, in such

embodiments the timing unit 10 is formed from one or more discrete components and may be electronic or mechanical in nature.

For the purposes of clarity the present invention will now be described by way of an example and with reference to Figure 2. In the example of Figure 2 the automated system is an automated pumping system including pump 16, float switch 13 and pump controller 12.

The power input 2 of monitoring and control system 1 is connected to grid power 3 by way of power supply cord 8. The power supply cord 8 may be hard wired to the monitoring system 1 or may alternatively be attached by way of a plug and socket, with input 2 being a socket. Power output 4 is electrically connected by way of a switching unit 5 to the power input 2. In the example of Figure 2 the switching unit 5 is a mechanical relay. The relay provides a default on position wherein an electrical connection 6 is provided between the input 2 and the output 4. The relay shown in Figure 2 is shown in an open position whereby no electrical connection is provided between the input 2 and output 4.

Controller 7 includes a microprocessor that monitors power consumption detector 9. The controller 7 should also be understood to encompass the peripheral circuitry associated with the microprocessor; sensors; drive circuitry and the like associated with the monitoring and control system 1. In the example of Figure 2 the power consumption detector 9 is a current transformer and associated current sensing circuitry. The power consumption detector 9 provides a signal representative of the voltage developed across the secondary sense winding of the current transformer due to current flowing from the input 2 through the current transformers primary winding to the output 4. The controller 7 monitors the signal and thereby determines whether power is being consumed from the power output 4. The controller 7 microprocessor includes a timing unit 10 that is configured to measure the period of time that power is consumed from the power output 4 in a particular cycle. It will be appreciated that in use the microprocessor resets the timing unit 10 when no current is detected as flowing through the current transformer and starts the timing unit 10 when current is detected as flowing through the current transformer. More advanced embodiments may also include a reset delay, whereby the microprocessor will not reset the timing unit 10 unless there has been no current consumed for a period of time. This additional feature captures fault conditions in which current is consumed on a regular but short duration basis.

In some embodiments the microprocessor may only start the timer if the current flowing through the current transformer is greater than a pre-defined threshold. The predefined threshold may be fixed during production of the monitoring and control system 1 , or may be adjustable by an end user. The timing unit may also include a fixed maximum on time value, or may be user configurable. This provides the option for a low cost fixed maximum on time unit as well as a more expensive unit which can be configured by the end user.

In the example of Figure 2 the output 4 of the monitoring and control system 1 is connected by way of power supply cord 11 to a pump controller 12. The pump controller 12 monitors the level of water 14 in water tank 15 by way of a float switch 13. When the water level in the tank 15 falls below a certain level the float switch 13 signals pump controller 12. The pump controller activates pump 16 to pump water from a water source 17 into the water tank 15. Once the water tank 15 is refilled to the correct level float switch 13 signals the pump controller 12 and the pump 16 is deactivated. Under normal conditions the float switch 13 trips regularly as water 14 is consumed from the tank 15. Water may be consumed in a number of ways such as by a domestic household, a watering system or the like. Based on the loading on the water tank, by the household, or watering system, a typical water consumption pattern can be determined. The controller 7 can then be programmed, or selected, to have a maximum on time that is longer than the longest recorded period of current consumption identified by the consumption pattern.

Under normal operating conditions the current consumption time of a typical pump operating cycle will be shorter than pre-determined time period of the monitoring and control system 1 and the switching unit 5 will remain in the default on position. If a fault occurs, such as the water tank 15 developing a leak or the float switch 13 sticking in the low position, the pump cycle time will exceed the pre-determined time and the switching unit 5 will be switched to the off position. In the off position power to the pump controller 12 and pump 16 is disconnected to prevent the loss of water, waste of power and/or potential damage due to flooding.

A further feature provided by the monitoring and control system 1 of figure 2 is measurement of the magnitude of the current consumed from the output 4. The current magnitude is compared to a maximum current limit programmed into the controller 7 and if the maximum current limit is exceeded the controller switches the switching unit from the default on position to the off position.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.