AU2642900A - Environmental conditioning control system - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD DIVISIONAL PATENT Invention Title: Environmental conditioning control system The following statement is a full description of this invention, including the best method of performing it known to me/us: FHP.S~rlCFNATflfl2y)I6.JAf7 2 CQ98265O2 3 3 Environmental conditioning control system Field of the invention The present invention relates to methods and apparatus for controlling environmental conditioning apparatus such as evaporative air conditioners, air conditioners, heating systems, cooling systems, humidity control systems.

Background of the invention Australian patent specification 628554 discloses a control means to thermostatically control a heating and cooling unit. The control means has a control device which is self contained and can be located at a place at which the temperature is to be monitored such as in a room. The control device includes a thermostat and adjustable temperature selector and RF transmission capability. This control system includes a temperature sensor and a comparator so that the output of the temperature sensor can be compared with the temperature selected so that if required the transmitter will transmit a signal to the air conditioning unit which will cause it to start or stop operation.

15 Australian patent specification 661449 discloses a remote control system for a heating or e cooling system. The remote control system includes a remote sensor in a hand held unit to sense (he temperature in a space. The sensor is provided with a transmitter so as to transmit a signal which represents the temperature sensed by the sensor to the control system which receives this signal and controls the heating and cooling process.

0 Australian patent application 681067 discloses a remote control system for an air conditioner wherein the portable unit has a temperature sensing means to measure ambient temperature near the portable unit. The portable unit includes a computational means to compare the ambient temperature measured with a preset temperature. The portable unit also includes computer software which controls the computational means to make the comparison and makes a calculation of the requisite speed required of the air conditioner to effect a change to the measured ambient temperature so that it approximates the pre-set temperature. The calculated speed being transmitted in the form of an encoded signal to the air conditioner which is responsive to receive the signal and change the speed.

Each of the prior art documents require continual transmission of the sensed temperature or other quantity of the remote control unit. This decreases the life of the batteries or dry cells powering the remote or hand held control unit. Once the battery life is terminated the air, room CQ9826502 3 .3 2 or environmental conditioning units generally cease to operate because signals are not being received.

It is an objection of the present invention to provide a remote control apparatus and method to ameliorate, at least in part, at least one of the disadvantages of the prior art.

Summary of the invention According to an aspect of the present invention, there is provided a control system for a remotely controlled environmental conditioning apparatus, said system including: a central control unit adapted to be coupled to the environmental conditioning apparatus and adapted to control an environmental condition in at least one-room space; a remote control unit'adapted to communicate control data to the central control unit, the remote control unit including: processing means programmed with a control algorithm; 00. sensor means coupled to the processing means and adapted to sense ambient temperature of the room space, and to input that ambient temperature to the processing means; at least one input means coupled to the processing means and adapted to allow a user to input a set point temperature selected by the user, into the processing means and at least one further environment influencing factor to the processing means; and a transmitter coupled to the processing means and adapted to transmit control data to the central control unit; 0000 20 where in use, the processor is adapted to process the inputed data in accordance with the control algorithm, to thereby generate the control data for transmission to the central control unit to thereby control the environmental condition of the room.

Also dicloseed is a method of controlling an environmental system, said system including: a central control unit having a receiver and a central processing device coupled to said receiver and adapted to process information received by said receiver; a remote measuring unit having an environmental parameter sensor, a remote processing device adapted to receive sensed information from said sensor and process said information in accordance with an algorithm, and a transmitter coupled to said remote processing device and adapted to transmit a signal representative of information processed by said remote processing device; and CQ98265(23.3 3 an environmental control unit adapted to receive information processed by said central processing device and control an environmental parameter in accordance therewith.

Preferably said remote measuring unit -an measure more than one environmental parameter or allows for input of data concerning environmental parameters to be processed by said algorithm.

Preferably there is a receiving unit coupled to said remote measuring unit and a transmission unit coupled to said central control unit and said central control unit transmits a receipt message to said receiving unit.

Also disclosed is a method of controlling an environmental system, said method including the steps of: 0 measuring at least one environmental parameter at a first location remote from said system; applying an algorithm to said at least one parameter at said first ~location to generate a single factor representative of said at least one parameter; transmitting said factor to a central control unit in said system, reverse operating said factor to produce an output from said "central control unit to control said system.

Preferably said method includes said central control unit transmitting a receipt message to said first location.

20 Preferably said first location upon receipt of said receipt message powers down until environmental factors change or specific operator inputs occur.

o Preferably said sampling is done by a hand held remote control device.

Preferably said transmitting and receiving operates by a polling method.

Preferably said hand held is the master in said polling method and said system the slave.

Preferably said master awaits a reply from said slave, such that said master re-transmits said factor when said receipt message in response to the immediately previous transmission is not received within a predetermined time.

Preferably said method includes the step of said first location powering down its receiver after sending its transmission, if predetermined events occur.

CQ98265(-3.3 4 Preferably said predetermined events are that the previous transmission was received and a receipt message sent, and only a minor change in conditions is being sent in said subsequent transmission.

Preferably said transmitting step from said first location is done by pulsing on and off a transmitter circuit at said first location, said circuit only consuming power when said circuit is pulsed on.

Preferably said transmitting step from said first location only consumes power when said circuit is pulsed on.

Preferably said central control unit shuts down if a transmission is not received from said first location within a time previously set by said first location. Alternatively, if a transmission from the first location is not received within a time previously set, said central control unit can control said environmental system from those parameters received previously from said first S location and or parameters sensed by said central control unit.

Preferably said method includes the sampling of ambient temperature in the vicinity of said 15 central control unit so as to provide a localised average reading of temperature fluctuations in ooo• S. the controlled environment.

Preferably said method includes the step of producing a pseudo control variable.

o Preferably said pseudo control variable is a function of said ambient temperature and said factor.

.0 Preferably said central control unit processes said pseudo control variable, said ambient temperature, and a information about the current mode of operation to produce a required effect on the operation of said system.

Aiso disclosed is a control system for a remotely controlled environmental conditioning apparatus, said system including: a) a central control unit to control said environmental conditioning apparatus which can change or maintain the environmental conditions in at least one room space, b) said central control unit including receiving and transmitting means to communicate with a remote control unit; CQ9826502 3 .3 c) said remote control unit having a receiving and transmitting means to communicate with said central control unit; d) said remote control unit including a processing means, a monitoring means and an input means; e) said remote control unit being able to produce an indication of the temperature of air surrounding said remote control unit; f) said remote control unit receiving from a user a temperature set point desired by said user; g) said remote control unit by said processing means applying a O function to at least said set point and said temperature to produce a factor for communication to said control unit.

Preferably said remote control unit processes a series of parameters in addition to said set point and temperature, said parameters including one or more of the following: data representative of heat loss or input rates into the room space;, the presence of insulation around said room; outside air temperature; outside weather conditions.

g Preferably said remote control unit transmits said factor and awaits an acknowledgment signal f'rom said central control unit.

Preferably said remote control unit awaits said acknowledgment signal for a predetermined time after which said remote control unit re-transmits said factor.

Preferably said remote control unit transmits to said central control unit a signal informing said central control unit as to when the next signal will be sent to said central control unit by said remote control unit. roo Preferably said remote control unit and central control unit transmit by a polling method.

Preferably said remote control unit is the master and said central control unit is the slave.

Preferably said remote control unit is able to power down its receiving means.

Preferably said remote control unit receiving means is powered down when a previous message was received and acknowledged by said central control unit and said remote control unit has produced a factor which is changed from the preceding factor by an amount within predetermined limits.

CQ98265023.3 6 Preferably said remote control unit transmitting means transmits by pulsing on and off said transmitting means, so that said transmitting means consumes power only when pulsed on.

Preferably said central control unit shuts down- if said c€ntral control unit does not receive a signal from said remote control unit within a time communicated to it previously by said remote control unit.

Preferably said central control unit receives a signal indicating, the temperature of return air entering said environmental conditioning apparatus from said at least one room space.

Preferably said central control unit produces a pseudo control variable by processing with a function said temperature of return air, said factor and current operating settings, so as to control said environment conditioning apparatus to produce a change or maintain the current conditions in said at least one room space.

Preferably said environmental conditioning apparatus is one of, or a combination of two or more of, the following: room heating apparatus; evaporative cooling apparatus; evaporative air conditioning apparatus; air conditioning apparatus; humidity controlling apparatus.

Preferably said central control unit continues controlling said environmental conditioning o apparatus if no signals after a first signal is received by said central control unit.

Preferably said central control unit produces said pseudo control variable without further reference to the remote control unit.

Preferably said remote control unit includes an EEPROM to receive and store signals from said 0 central control unit concerning faults, which have occurred in said environmental conditioning apparatus.

Brief description of the drawings An embodiment of the present invention willnot be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a block diagram of the operation of a hand held remote control.

Figure 2 illustrates a block diagram of the central control unit which interacts with the remote control unit.

Figure 3 illustrates a flow diagram of the receiving topology.

Figure 4 illustrates a flow diagram of the transmission sequence.

CQ98265023.

3 7 Figure 5 illustrates diagrammatically the system topology.

Figure 6A and 6B in combination illustrates the circuit diagram of the remote control hand held unit of Figure 1, with links A to N on Figure 6A indicating connection into links A to N on Figure 6B.

Figure 7 illustrates a schematic circuit diagram of the central control unit.

Detailed description of the embodiments Illustrated in Figure 1 is a flow chart of a hand held remote control unit embodying the present invention. A micro-controller user interface or hand held controller 2 is functionally depicted in Figure 1 and Figure 6.

The hand held controller 2 includes a power control 4 which once switched on serves utility functions 6 and will sense ambient temperature 8, around the hand held controller 2. The ambient temperature 8 is measured with an average calculated of each of the measurements.

Preferably the hand held controller 2 will monitor the ambient temperature around it at intervals of approximately 1 to 2 minutes, so as to detect any major changes in the environmental 15 conditions. While a longer period between monitoring of ambient temperature can occur, it is o. preferred to be of 1 to 2 minutes as users like to be able to see some reaction in the environment .conditioning apparatus.

The ambient temperature is monitored by an analogue to digital converter 8A as illustrated in figure 6. Hereinafter the converter 8A will be referred to as the A/D converter 8A. The A/D converter 8A is a specialised circuit which has a small component count and is low in current consumption. It converts the resistance of a high initial resistance thermistor to a voltage pulse which is proportional to the resistance in its width in time. The A/D converter 8A uses S differential pair of transistors which are used to compare the thermistor against fix references.

There is one control line to start conversion and one output from where the change of state, and hence conversion signal proportional for resistance, is read.

Operation of the A/D converter 8A is as follows. Normally the supply to the A/D converter 8A is turned off. It is only turned on when an A/D reading is required. To start conversion the transistor Q8 is pulsed on which discharges capacitor C9. Transistor Q7 turns off and transistor Q6 turns on. This turns transistors Q5 and Q4 off.. The output state of resistor of R16 is low.

Capacitor C9 charges through thermistor THI until base emitter of transistor Q7 is higher than transistor Q6. Then transistor Q7 turns on, thus transistor Q6 turns off, and transistor Q5 turns CQ98265(3.3 8 off, transistor Q4 turns on while the output state across R 16 goes high. The time that the voltage across resistor R16 is low, is proportional to the charge time of thermistor TH1 in parallel with resistor R22. In the non conversion state no current is drawn by the A/D converter 8A The circuit of A/D converter 8A is calibrated via variable resistor VR1 to alter the reference voltage.

The hand held controller 2 also allows for an input by button or rheostat means of a set point to set the temperature at which the user desires the room to be. Other parameters 14 can be introduced as input into the hand held controller 2, such parameters being related to the environmental conditions. This will allow the embodiment of the invention to operate with less compromise relating to the environmental conditions and operational factors when compared with prior art systems. These other parameters 14 can be input into the hand held controller 2 and these factors can be included in the control algorithm to assist in refining the temperature control. The algorithm used to implement the control of temperature utilises fuzzy logic to implement parameters such as insulation gradient, season, the actual weather conditions outside, the time of day etc.

The on-off/time zones etc box 12 are other settings that can be entered by the user which set the mode of operation of the environmental conditioning apparatus, such as cooling or heating, or whether they want it run on auto, or time zones, on or off, ducting zones, economy etc. The humber of parameters or settings located or used will be dependent on whether the environmental conditioning apparatus is a reverse cycle air conditioning or central ducted heating or evaporative cooling or other type of environmental conditioning units.

The hand held controller 2 preferably operates off 3AAA size dry cells or batteries if it is configured for radio frequency wireless communication. The hand held controller 2 will have S preferably a key pad and feed back is provided to the user via an LCD display.

The hand held controller 2 includes a central processing unit to process all the user settings and the measured temperature to provide an advisory control output which is sent by the hand held controller 2 to a central control unit which is located in the environment conditioning apparatus.

The environment conditioning apparatus need not be located at the same location to which the hand held controller 2 transmits. The actual apparatus may be located at a further remote location and a hard wired or other connection is made to the receiver and or the central control unit.

A load capacity factor once calculated awaits the completion of the material to be encoded. The other material to be encoded includes the frequency of transmission that will occur between the CQ98265(23.3 9 hand held controller 2 and the central control unit. The frequency of transmission is how often the hand held controller 2 will transmit to the central control unit. The hand held controller 2 may, for example, be programmed so that oncethe temperature of the air around the hand held controller 2 is measured a load factor produced and sent as a first transmission to he Central control unit, then the next time of transmission will be within five minutes of the first transmission. Thus hand held controller 2 will communicates to the central control unit, at the time of sending the first transmission that a second transmission will be sent again in five minutes time.

However, as the conditions in the room stabilise to the desired temperatures and or other conditions as set by the inputs of the user, the hand held controller 2 may only transmit every minutes or so and will inform the central control unit accordingly. This ensures that the central control unit will not shut down until the time predetermined for the receipt of the next signal has passed with a window to either side of designated time being allowed for in the system.

oo The other information which will be transmitted namely the mode of operation (such as cooling, heating, auto, time zones, ducting zones, economy on or off) are generally static all through the operation of the environmental conditioning apparatus.

The three units of information namely the mode of operation 20, the frequency 18 and the load o.

capacity 16 are encoded by an RF encoder 22 and sent to the transmitter 24 for transmission through to the central control unit. In preparing to transmit, the hand held controller 2 transmits with a sequence as illustrated in figure 4.

Then the other variables which were input at items 12 and 14 have a function applied to them to produce a load capacity factor (see item 16 of Figure Before this data is transmitted the system is interrogated to ensure that there has been a sufficient change in temperature with respect to the change in time. This change in temperature per unit time must be of a predetermined magnitude whereby if the change is greater than the predetermined magnitude the load capacity factor 16 will be encoded at 22 then transmitted at 24.

If the change ambient temperature with respect to time is not greater than the predetermined magnitude then transmission of the load capacity factor 16 will not occur as seen by branch 26 of Figure 4. At this point a comparison with the maximum elapsed time which is that time preselected by the hand held controller 2 and been previously communicated to the central control unit) is made whereby if the maximum lapsed time has elapsed the load capacity factor will be encoded at 22 (see branch 28) and transmitted at 24. If maximum time has not elapsed CQ98265023.3 then branch 30 will be followed and the temperatures will be re-read and the variables and load factor 16 recalculated.

If one of a few critical mode of operation parameters, such as heating/cooling, fan speed are adjusted, the hand held controller will transmit the change to these critical parameters irrespective of the maximum time elapsed or the change of ambient temperature with respect to time being of a large enough magnitude.

As the transmission 24 takes place, or shortly before transmission takes place, the hand held controller 2 will deliver power to its receiving circuit 34 so as to enable the circuit 34 to receive an acknowledgment signal from the central control unit.

.0 Referring now to Figure 4 if the acknowledgment 38 is received branch 40 will be followed and the process will begin again at the time predetermined by the hand held controller 2. At item 18 if acknowledgment 38 is not received within a specified time the branch 42 is followed whereby the transmission is attempted again. The transmission will be repeated for up to say five attempts have been made until such time as the acknowledgment 38 is received. If the 2 15 acknowledgment is not received within five attempts branch 46 will be taken whereby the process will begin again until such time as acknowledgment is received.

Items 22 and 36 functionally represent the processes involved in transmitting and receiving information between the hand held controller 2 and the central control unit. The receiving circuit 34 is controlled by the hand held controller 2 to turn on and off the power to the receiver so as to conserve power when the hand held controller 2 is not receiving data from the central o control unit. As the central control unit is mains powered it can keep its transmitter and receiver functioning at all times, or at all times the system is on.

There are many methods of establishing communication between two communicating devices and the method that is preferred is a polling method whereby one unit, in this case the hand held controller 2, acts as the master in the communication system and initiates communication by transmitting a command or request to a slave unit. In this case the slave unit is the central control unit. The central control unit as a slave only transmits in response to a valid command or request received from the master unit being the hand held controller 2.

The transmitted message utilises a standard protocol such as a message identifier and check sum to ensure the required destination receives the message and is able to verify the reliability of the message.

CQ98265023.3 11 In the communication system of this embodiment the master transmits and then waits for a reply from the slave to acknowledge the transmission within a fixed time frame. If a reply is not received the master will then re-transmit until a fixed number of attempts in this case 5 before giving up on the transmission.

In the preferred embodiment there is an extra step in the communication method which has been added to conserve power. This extra step allows the master( i.e. the hand held controller 2) to decide that it does not require acknowledgment from the central control unit and actively disables the receiver 34 in order to conserve power. The extra step is preferably performed when the last message sent by the hand held controller 2 was acknowledged successfully by the central control unit. In this case when hand held controller 2 next calculates the load capacity 16 and compares this newly calculated load capacity and compares it to the previous load capacity, and finds that only a minor change in the load capacity has taken place, (which is reflected by a change in temperature with respect to unit time) such that the change is not critical to the operation of the environment conditioning apparatus, then central control unit does not reply to 15 the next transmission as it is instructed not to by the hand held controller 2. Whilst it would save even more energy for the hand held controller 2 not to transmit at all, the transmission may be required to keep the scheduled transmission previously communicated to the central control unit.

When the receiver 34 is not turned on the hand held controller 2 may transmit several times to increase the probability of reception on the control unit. Even though several transmissions are sent, overall power is still saved due to the nature of transmitting.

When transmitting data the transmitter 24 operates the transmitter circuit by pulsing it on and off at varying time intervals, to represent the data bits being transmitted. In this way the transmitter circuit only consumes power when the circuit is pulsed on.

When receiving, the receiver circuit 34 is preferably be powered continually prior to receiving the acknowledgment transmission from the central control unit. This will ensure that the receiving circuit is stabilises during the reception of the message and after the message in case the message received was not a valid transmission. The receiving circuit 34 can be powered up as the transmission is occurring providing that the receiving circuit is sufficiently stabilised.

The receiver topology of the central control unit is illustrated in Figure 3. A message is received at item 34 and decoded at item 38. During decoding a test for any errors, by means of a check sum, is made. At item 50 a check sum correlation is performed to ensure that the data was not CQ98265fl23.3 12 corrupted during transmission. If the answer is yes and the data is okay, then branch 52 is followed and an acknowledgment transmission is made at 124 in Figure 2.

During the transmission made at 124 in Figure 2, the transmission from the hand held controller 2 is not only acknowledged but the status of the central control unit (and any faults that may have been found therein by a fault detection and watch dog systems in the central control unit) is generated at 154 and committed to encoding at 122. One advantage of this is that the hand held controller 2 which includes an EEPROM can be interrogated by a service personnel should a fault be reported to the manufacturer or service contractor. This way the service person will be able to identify the source of the problem without having to visit each site of the environment conditioning apparatus.

The information or data received at 134 of Figure 2 by the central control unit is processed so that the load capacity factor 116 (16 as generated by the hand held controller 2) is processed so as to produce at 116 and 118 so as to produce a pseudo control variable 200.

The pseudo control variable 200 is a control variable that is a function of the local ambient 1% 5 temperature 202 and the load capacity 116 which has been received from the hand held controller 2. The pseudo control variable 200 is only updated on each successful reception from the hand held controller 2.

•*ga The pseudo control variable 200 together with the local return air ambient temperature 202 are both used by the control algorithm 204. The mode of operation 120 also decoded at 138 and is also used by the control algorithm 204. The frequency of transmission 118 received by the central control unit then is communicated to the fault detection and watch dog systems which are software routines in the central control unit to monitors communication, safe operating 9 conditions. An update of a hardware watchdog which ensures correct operation of the software 206. The control algorithm 204 takes all these inputs to produce a series of outputs 208 which are then used to activate relays or other control mechanisms to control motors, compressors, burners, fans or other systems of the environmental condition system.

A power saving facility in the embodiment of Figure 1 to Figure 5 is the communication protocol that information in the transmitted message which the hand held controller 2 transmits to the central control unit indicating how often the hand held controller 2 will be transmitting.

This allows the hand held controller 2 to reduce the number of transmissions when the conditions are stable and not changing, or increases the number of transmissions as the need arises. For safety reasons the central control unit is designed to shut down if it loses CQ98265023.3 13 communication for an extended period of time with the hand held controller 2. Therefore, the environmental conditioning apparatus is designed to shut down if a signal is not received from the hand held controller 2. Thus it is highly desirable that the central control unit knows how often the hand held controllei2 intends to transmit so that it is prevented from shutting down until such time as the transmission has been received.

An optional feature of the embodiment is the use of the pseudo control variable 200 to allow the central control unit to continue operating when no signal is received from the hand held controller 2. The pseudo control variable 200 whilst generated as a matter of course can be utilised to ensure the running of the environment conditioning apparatus even if the central control unit does not receive another signal from the hand held controller 2. Providing the hand held controller 2 has transmitted once, then the load capacity-factor 16 will be calculated and transmitted and the load capacity factor 116 will have been received by the central control unit.

oPseudo control variable 200 will keep being generated with the last load capacity factor 116 S received by it so that the pseudo control variable 200 can be continually refreshed by comparing the load factor with local return air ambient temperature 202.

.00.

The local return air ambient temperature 202 is produced from a temperature sensor positioned 9* in the return air flow of the intake duct of the central control unit. It provides a localised average eading for the temperature fluctuations in the controlled environment.

ooe¢ -o The control algorithm 204 takes the local ambient temperature 202, the pseudo control variable 200, the mode of operation 120 and if there are no faults 206 present, outputs to the required Le hardware so as to produce a desired effect on temperature of other perimeter being tested for.

The insertion of the local ambient temperature 202 and pseudo control variable 200 in the S: control algorithm, allows the central control unit to have some input into the final output that is produced by the environment conditioning system. This allows the central control unit to fine tune the load capacity with respect to temperature fluctuations in between transmissions, but also allows it to respond to the output requirements of the hand held controller 2. Therefore the central control unit could run for longer periods of time without receiving any transmissions from the hand held controller 2 while maintaining a suitable control of the room temperature.

Even if the local temperature sensor fails to operate, the central control unit will still respond directly to the load factor 116, (previously 16) regardless of what the local ambient temperature 8 sensor is reading.

CQ98265023.3 14 The pseudo control variable 200 is not the same as the set point 10, but the set point 10 is a factor which goes into generating the pseudo control variable 200 which accounts for many more inputs than just the set point 10 and ambient'temperature 8.

In the hand held controller 2 the Load Factor 16/116 can be calculated as: n L.F Wj(Pi) Wo(P) W2(P 1

)+W

2

(P

2 Wn (Pn) i-0 Where:- L.F. is the Load Factor.

W

i is a weighting function applied to the control Parameter Pi which can be implemented using a fuzzy set. The weighting functions Wi can be derived from testing or derived mathematically.

Pi is a control parameter to which a weight is applied. Each control parameter can in itself be a result of another equation such as the temperature difference, for example set point temperature (Pt) or other sensor inputs such as the Relative humidity or other parameters such as insulation gradient, season, the actual weather conditions outside, the time of day etc or even be a combination of other control parameters.

On the relay board side, that is in the central controller unit the pseudo control variable 200 can be calculated by: P.V. Kox IKjSj °0o. j-i Where:- P.V. is the pseudo control variable.

L.F. is the Load Factor 16.

Sj are local control variables.

Kois the weight applied to the Load Factor.

Kj are the weights applied to the local control variable.

The output O can then be calculated as: KjSj j=O CQ98265023.3 Where:- O is the output applied to achieve the desired effect.

P.V. is the pseudo control variable.

Sj are local control variables.

Kj are the weight applied to the local control variables.

The local control variable Sj can be the local temperature average, or the rate of change in temperature etc.

The weights Kj can be derived mathematically or through experimentation testing.

This method allows either the hand held controller 2 or relay board on the central control unit °0 equations to be independently changed without effecting the compatibility between the hand :i.

held controller 2 and the central control unit.

Illustrated in figure 7 is a cricuit diagram of a central control unit for use with the hand held controller as described above.

It will be understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

The foregoing describes embodiments of the present invention and modifications, obvious to those skilled in the art can be made thereto, without departing from the scope of the present invention.

Claims (15)

1. A control system for a remotely controlled environmental conditioning apparatus, said system incfuding: a central control unit adapted to be coupled to the environmental conditioning apparatus and adapted to control an environmental condition in at least one room space; a remote control unit adapted to communicate control data to the central control unit, the remote control unit including: processing means programmed with a control algorithm; sensor means coupled to the processing means and adapted to sense ambient temperature S of the room space, and to input that ambient temperature to the processing means; at least one input means coupled to the processing means and adapted to allow a user to Sinput a set point temperature selected by the user, into the processing means and at least one further environment influencing factor to the processing means; and a transmitter coupled to the processing means and adapted to transmit control data to the a..o central control unit; where in use, the processor is adapted to process the inputed data in accordance with the control algorithm, to thereby generate the control data for transmission to the central control unit to thereby control the environmental condition of the room.

2. An environmental system including: a central control unit having a receiver and a central processing device coupled to said receiver and adapted to process information received by said receiver; a remote measuring unit having an environmental parameter sensor, a remote processing device adapted to receive sensed information from said sensor and process said information in accordance with an algorithm, and a transmitter coupled to said remote processing device and adapted to transmit a signal representative of information processed by said remote processing device; and an environmental control unit adapted to receive information processed by said central processing device and control an environmental parameter in accordance therewith. CQ98265023.3 17

3. A system as claimed in claim 2 wherein said remote measuring unit measures more than one environmental parameter or allows for input of data concerning environmental parameters to be processed by said algorithm.

4. A system as claimed in claim 2 or 3 further comprising a receiving unit coupled to said remote measuring unit and a transmission unit coupled to said central control unit and said central control unit transmits a receipt message to said receiving unit. A method of controlling an environmental system, said method including the steps of: measuring at least one environmental parameter at a first location remote from said system; applying an algorithm to said at least one parameter at said first location to generate a single factor representative of said at least one parameter; transmitting said factor to a central control unit in said system, reverse operating said factor to produce an output from said central control unit to control said system. 0ooo

6. A method as claimed in claim 5 further comprising the step of said central control unit transmitting a receipt message to said first location. o A method as claimed in claim 6 wherein said first location upon receipt of said receipt message powers down until environmental factors change or specific operator inputs occur.

8. A method as claimed in in claimed in claim 5 further comprising the step of said first location powering down its receiver after sending its transmission, if predetermined events occur. A method as claimed in claim 5 wherein said predetermined events include that the previous transmission was received and a receipt message sent, and only a minor change in conditions is being sent in said subsequent transmission. A method as claimed in any of claims 5 to 9 wherein said transmitting step from said first location is done by pulsing on and off a transmitter circuit at said first location, said circuit only consuming power when said circuit is pulsed on.

11. A method as claimed in claim 5 wherein said transmitting step from said first location only consumes power when said circuit is pulsed on. CQ98265023.3 18

12. A method as claimed in claim 5 wherein said central control unit shuts down if a transmission is not received from said first location within a time previously set by said first location.

13. A method as claimed in claim 5 wherein, if a transmission from the first location is not received within a time previously set, said central control unit can control said environmental system from those parameters received previously from said first location and or parameters sensed by said central control unit.

14. A method as claimed in claim 5 further including the sampling of ambient temperature in the vicinity of said central control unit so as to provide a localised average reading of S temperature fluctuations in the controlled environment.

15. A method as claimed in claim 5 said method further utilises a pseudo control variable which is a function of said ambient temperature and said factor.

16. A method as claimed in claim 15 wherein said central control unit processes said pseudo control variable, said ambient temperature, and information aboh t the current mode of operation to produce a required effect on the operation of said system.

17. A control system for a remotely controlled environmental conditioning apparatus, said system including: a central control unit to control said environmental conditioning apparatus which can change or maintain the environmental conditions in at least one room space, said central •9 -control unit including receiving and transmitting means to communicate with a remote control unit; a remote control unit having a receiving and transmitting means to communicate with' said central control unit, said remote control unit including a processing means, a monitoring means and an input means; and being able to produce an indication of the temperature of air surrounding said remote control unit; said remote control unit receiving from a user a temperature set point desired by said user and utilising said processing means to apply a function to at least said set point and said temperature to produce a factor for communication to said control unit.

18. A control system as claimed in claim 17 wherein said remote control unit processes a series of parameters in addition to said set point and temperature, said parameters including one :Q98265(23.3 19 or more of the following: data representative of heat loss or input rates into the room space;, the presence of insulation around said room; outside air temperature; outside weather conditions.

19. A control system as claimed in claim 17 wherein said remote control unit transmits said factor and awaits an acknowledgment signal from said central control unit. *SSS S *og «o