FR2726635A1 - METHOD FOR CONTROLLING A HEATING / COOLING SYSTEM THROUGH A THERMOSTAT AND SYSTEM CONTROLLED THEREBY - Google Patents

Abstract

A programmable thermostat (10) for controlling the actuation, for example of a central heating system, as a function of the temperature, is powered by batteries so that it is not necessary to connect it to a mains supply. . The central heating system is controlled by a switching circuit (22) which can take a first position, in which the central heating system is activated, and a second position in which the system is deactivated. The thermostat (10) contains a processing unit (12) which monitors the power level of the batteries. If said level remains below a preset value for a preset period of time, an alarm signal is emitted. If the user does not intervene in response to said signal, the thermostat (10) switches off the central heating system before the batteries are too exhausted to carry out the switching.

Description

a su-om ne 'a aupmessrpToIa; /; nqo sp ItIexdde un leuuoTIouo eSTej inod

  apuemmoo ep; T4TsodsTp a -uuuesadmooXuess9p; oez; / s2 ;; neqD ap smQsxs un, p epurmoo ep apeoojd un uoTI.TsodsTp e sIm: sa I; 'UOTiUeAuT ae: uas) id eI ap soeds-e -aTmeid un snos sum no sInp, .. uos snssep-To snboAsemsuqoid sel lenbal suep apuemmos ap gpsood un uo;; TsodsTp e asai.mep nq.nod e uoTIueAuT

  eeSuoload spoT.ad aun 4uepued uoTsue.

  snos uSemallenu; TuoD a.eJi -ea1ueo Se2 nnq1o ep eme4sXs el eainpuoo euaAned snssep-To sae; .Iaop saourqsuooaTo sel 'SpoT.Id sn2uol sun nuepued sTIled 4uos xnaTI sep smuQn

  1e1ueo aiegneqo ap ama; sgs al IS 'aqoavm ua eaIs%.

  9mi.sÀs el 'aqostlm ua 4se lrilJues 92e ;; ne-q ap amis4s el enbsiol eldmexd ed'% Inpoid es elao FS 'Qsomaeq% np uoTe nmmo eI Ian4oes ;; a lnod seq do.i 4se aQouessTnd ap neATu el% uTod un jaeAIli% ned IT 'aldmexe ria assTQq XXsomaaq, 4 el 4ue uamTiv salTd sep aouQssTnd ap nlATu ael Ts.asod es 4usAnad smsozlqoid sap s- oJ9anoj sal! d eç% esom-aiq a aldmaxaed; aldmaxaed; neqD ap emgtXsfs un.apuemmoD sçes uo ap Cm; L un osaAesTITIn ae: i auIssp% usomeg un auiaouoo uollueAuT, T '1ae! noled uS' apgooid eo led 9puemmoo ame% 4sXs un% qsoamp; a, p apuemmoo ap apcooid an auieouoo uo! ueAul suasgtd QI Sú99gZE battery thermostat intended to selectively activate and deactivate said control device as a function of measured and desired temperatures, the method comprising the steps of monitoring the power level of a cell or batteries which supply said thermostat, to emit an alarm signal when the power level is below a predetermined value and, after a predetermined time after the emission of said alarm signal, to cause the thermostat to deactivate the control device and

keep disabled.

  A method according to an embodiment of the invention avoids the risk that the system, for example a central heating system, remains supplied when

  the battery power level of the thermostat drops below

  below the predetermined value.

  In one embodiment, the thermostat is arranged to deactivate the control device and keep it deactivated soon after the alarm signal is issued. For example, the system can be effectively stopped by keeping the control device in the deactivated state, only a few seconds or milliseconds after the alarm signal has been sent. However, in practice, it is generally preferable that an "exhausted battery" alarm signal is produced for an extended period, for example several days, in order to allow the replacement of the battery or batteries. Consequently, it is generally preferable for the control device to be kept deactivated only when several days have elapsed since the emission of said alarm signal. In general, it should also be ensured that the control device will not be deactivated if the alarm signal has been issued in error and / or if the batteries have been replaced. It is therefore preferably made arrangements for said thermostat to be brought to keep the control device deactivated only if the power level generally remains at said predetermined value or below it for a second predetermined time. In general, once the battery power level has started to drop, an alarm signal should be given to allow the batteries to be replaced. If the batteries are not replaced, it is desirable to ensure that the control device will be disabled and kept disabled by the thermostat before the weakening power supplied to the thermostat becomes too low to produce the

switching of it.

  However, it is also useful not to have to monitor continuously and / or periodically the actual power levels available. This can be achieved by having the alarm signal initiate a timing sequence and having said thermostat deactivate the controller upon completion of said timing sequence unless higher power levels are detected. In one embodiment, the method is applied to the control of a central heating system equipped with a control device in the form of a programmer for selectively actuating heating means of this system. Such programmers can be provided with a means forming a processing member and with a memory. If necessary, the means provided for monitoring the power levels of the thermostat batteries and for causing the thermostat to keep the programmer deactivated can be provided in the latter. However, in a currently preferred embodiment, the thermostat is itself provided with a means forming a processing member arranged so as to cause it to keep the programmer deactivated after a predetermined time after the emission of said

alarm signal.

  Preferably, the transfer of data from the programmable memory of said thermostat to a non-volatile memory of the latter is carried out after a predetermined time after the emission of said alarm signal. This allows the data in the programmable memory to be saved, even when the battery power supplied to the thermostat is decreasing or decreasing. In current systems, the control device or programmer is connected by cable to the thermostat or to each thermostat to be controlled by it and, in such circumstances, the thermostat may be provided with a latching relay intended to open or to close at least one switch to activate

  or deactivate the circuit of the control device.

  However, it is also possible to arrange the necessary switch or switches in the control device, so that the thermostat produces only output control signals to establish the position of the switches. In this circumstance, although the thermostat and the control device may be physically connected, it may be preferable for the communication between the two devices to be made by transmitting and receiving means, for example by a high frequency link.

(H.F.).

  The present invention also extends to a heating / cooling system comprising a control device for actuating a heating / cooling device and at least one battery thermostat intended to selectively activate and deactivate said control device as a function of measured temperatures and desired, said system of

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  heating / cooling further comprising processing member means for monitoring the power level of a cell or cells supplying said thermostat and emitting an alarm signal when the power level is lower than a predetermined value, said means the processing member being arranged so as to cause said thermostat, after a predetermined time after the emission of said alarm signal, to deactivate said control device and

keep it disabled.

  The processing means for monitoring the power level may be provided in the controller, in the thermostat, in a separate unit, or may be distributed among any of these locations. However, in a preferred embodiment, the member means

  treatment is contained in said battery thermostat.

  In a preferred embodiment, said processing means is arranged to initiate a timing sequence to deactivate the controller after said predetermined period of time, unless higher power levels are detected by said

means forming a processing organ.

  In one embodiment, said thermostat comprises a programmable memory and a non-volatile memory and said processing member means is arranged so as to cause, after a predetermined time after the emission of said alarm signal, the transfer of data from said programmable memory to

said non-volatile memory.

  Preferably, said heating / cooling system

  This comprises a central heating system equipped with said control device for actuating

  selectively the heater of this system.

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  In one embodiment, the control device or programmer is connected by cable to the thermostat or to each thermostat to be controlled by the latter and, said thermostat or each thermostat may be provided with a latching relay intended to open or to close at least one switch to activate or deactivate the control device. However, it is also possible to arrange the necessary switch or switches in the control device, so that the thermostat produces only output control signals to establish the position of the switches. In this circumstance, although the thermostat and the control device may be physically connected, it may be preferable for the communication between the two devices to be by transmitting and receiving means, for example by a

high frequency link (H.F.).

  In another aspect of the present invention, there is provided a thermostat comprising a switching circuit intended to - generate control signals for activating and deactivating a controlled circuit selectively, and a means forming a processing member for controlling the operation of said circuit switching circuit, said thermostat being arranged so as to be supplied by one or more batteries and said processing member means being arranged so as to monitor the power level of the battery or batteries, for emitting an alarm signal when the power falls below a predetermined level, and said processing member means being arranged so as to lock said switching circuit in a state where circuit deactivation control signals are produced, after a time

  predetermined after the emission of said alarm signal.

  In one embodiment, said switching circuit produces output signals to cause the controlled circuit to be activated and deactivated. In this regard, the circuit to be controlled may be connected to the switching circuit to receive the output signals therefrom or it may receive the signals by transmission from said switching circuit. In addition and / or as a variant, said switching circuit can be arranged so as to adopt one of the two states, the first state being a state of activation of the circuit and the second state being a state of deactivation of the circuit . For example, the switching circuit may be a normally open or normally closed switch. Preferably, the switching circuit comprises a latching relay which is bistable and can therefore adopt two states, for example a first state in which the contacts of the relay are closed and a second state in which the contacts of the

relays are open.

  In one embodiment, the processing member means is arranged so as to lock said switching circuit shortly after the alarm signal is transmitted. That is to say that said predetermined time can be of the order of seconds or milliseconds. However, in a preferred embodiment, it is generally preferable to provide a "dead battery" alarm for an extended period, in order to make it possible to replace the battery. For example, said predetermined time may last several

  Days after the issuance of said alarm signal.

  Preferably, arrangements are made for said processing member means to be made to lock said switching circuit only if the power level generally remains at or below said predetermined value for a period of time.

second predetermined time.

  In a preferred embodiment, arrangements are made for the transmission of said

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  alarm signal triggers a timing sequence in said processing means for locking said switching circuit after said predetermined time, unless higher power levels are detected. Embodiments of the present invention are described below, by way of example, with reference to the accompanying single figure which shows the circuit diagram of a programmable thermostat in one form.

  of the present invention.

  The present invention is described below in particular with regard to the arrangement of a programmable thermostat in a central heating system

  having a programmer for controlling the system.

  Such systems are widely used in the UK.

  Xais it is understood that the present invention is not limited to a central heating system and that it is not limited to the type of heating system either.

  central heating commonly installed in the UK.

  The control methods of the invention can be applied to the control of any heating / cooling system. In addition, although the invention is described by means of the specific example of a programmable thermostat, it will be readily understood that the control devices described here can be adopted by a control circuit specially provided for this purpose, incorporated in the thermostat or separate from it. The figure represents the circuit diagram of a programmable thermostat 10. The thermostat comprises a processing unit 12 which includes a memory 14 and a microprocessor 16. A clock circuit 18 provides

  a real time measurement at the processing unit 12.

  In known manner, the clock circuit 18 can comprise a quartz oscillator connected to a chain of dividers. The thermostat 10 also contains a device 20 for measuring the temperature. This temperature measuring device 20 can have any suitable structure. The device 20 is intended to provide an indication of the actual temperature measured at the place where it is located and to deliver this

  information to the processing unit 12.

  In known manner, there are stored in the memory 14, software programs for controlling the thermostat 10. In addition, the memory 14 also stores the desired temperature to be reached by the central heating system with which the thermostat 10 is to be used . In this regard, the stored temperature can be a single temperature. Alternatively, a number of different temperatures, desired at different times or under different circumstances, can be stored. In one embodiment of a programmable thermostat, it is preferable to store in memory 14 indications, not only of the desired temperatures, but also of the moment at which each temperature is required. This allows the processing unit 12 to identify at any time, given by the clock 18, the desired temperature. This information will generally have been preprogrammed in memory by the user. The desired temperature is then compared with the actual measured temperature supplied by the temperature measuring device 20. In this regard, the actual quantities compared by the processing unit can be, for example, temperatures or functions or signals representative of temperatures. It will be readily understood that if the thermostat 10 determines that the ambient or effective temperature, measured by the measuring device 20, is lower than the desired temperature, there is a need to activate the central heating system to raise the effective temperature to the level of the one that is desired. In addition, once the desired temperature has been reached, the central heating system must be stopped. The central heating system is controlled by means of a switching circuit 22 arranged so as to produce an output signal, indicated at 24. Preferably, the switching circuit 22 is a bistable latching relay. The switching circuit 22 can be arranged so as to deliver signals to a controller or programmer of the central heating system. For example, the switching circuit 22 can be controlled so as to activate or deactivate the control device and, consequently, the central heating system. As a variant, the switching circuit 22 may include physical contacts, such as relay contacts, connected so as to control the programmer of the

central heating system.

  Whatever the nature of its output signal, the thermostat, which controls the actuation of the heating system as a function of temperature, is powered by batteries. Battery power is preferred because there is no need to connect the thermostat, for example to an AC power supply, which simplifies installation. However, it will be readily understood that the batteries can wear out, which is the source of difficulties. A thermostat according to the present invention is designed to eliminate the problems traditionally associated with thermostats powered by

Battery.

  As described above, the switching circuit 22 can take a first position in which the central heating system is activated and a second position in which the system is deactivated. The switching circuit 22 is controlled so as to take one or other of these positions under the action of the microprocessor 16. In fact, as there may be the possibility that the switching circuit 22 takes a position other than that required, the microprocessor 16 is arranged so as to periodically send to the switching circuit 22 reaffirmation control signals, so that one can be assured that the switching circuit 22 is in the

chosen position.

  Continuously and / or periodically, the microprocessor 16 monitors the power level of the batteries (not shown) which supply the thermostat 10. The power level of the batteries is compared with a preprogrammed or preset value and if the power level drops to - below this value, an alarm signal is emitted. It goes without saying that the alarm signal can be of any type. It is usually preferable that the thermostat is provided with an indicating means, for example in the form of a display element, and that the signal at low voltage level

  or a flashing indication of "dead batteries".

  The voltage level from which a "dead batteries" alarm is issued is preferably chosen so that it allows the thermostat to continue operating efficiently for several days. By this means, it is hoped that the user will notice the alarm signal and replace the batteries so that the thermostat is reset and the

normal operation continues.

  If the user does not intervene, for example due to an absence, the thermostat is arranged so as to stop the central heating system before the batteries are too exhausted to carry out the switching operation. In this way, one can be assured, for example, that if the occupant of the premises has left for a certain period, he will not find on entering a situation in which the heating system has remained on for a prolonged period. Since it is preferable not to have to monitor the effective level of the batteries during the period in which they are discharged, the microprocessor 16 initiates, upon the emission of the alarm signal, a timing sequence to monitor the time elapsed. When the elapsed time reaches a predetermined value, preferably several days according to what has been indicated previously, the microprocessor 16 actuates the switching circuit 22 to stop the central heating system. In addition, arrangements are made to ensure that the relay of the switching circuit 22 is locked when stopped, that it cannot be supplied with power and that the rest of the thermostat 10 is stopped, with the exception that the indicator of "exhausted batteries" changes state. For example, if the "dead batteries" alarm was emitted by means of a flashing light-emitting diode or another light element, this light element is permanently on when the circuit is stopped. Apart from the alarm lighting, the thermostat is now in a state in which all other activity is prohibited until the batteries have been replaced. This "stop" state can continue for some time, because arrangements are made for the light alarm to use very little power. It is desirable that the light alarm is always maintained, in order to inform the user,

  upon his return, the nature of the problem.

  It will be readily understood that if a programmable thermostat is put into an "off" state, the data stored in the programmable memory 14 will be lost. This means that the user will have to reprogram the device after installing new batteries. To avoid this, a non-volatile memory can be provided in the thermostat such as a NOVRAM - - + eAej a9 epuieme e-luesea QI a 'aupezD np% uine inod 9aijoi, s uo, T anb sues laiauesasdai aap eTallanb allal uo. uaAuT.TV segl.-odde atn% ueAnndsaluv! aA no suoT! Qo; Tpom saJne, a% uemessTpToJ.; ea 5i ap no t ;; nqo iap TmesXsIanba-% odm;, u inod apupu = oD pp rt = zsXs% noi g aenbTIddv ae 4nad uoT'4ueAu, r 9 speN 9e2ua L,; jn-e-qc ap amvaw4sXs un suep aIqeummeIzo.d '4somiqe un, p uo! .TsodsTp eI ap sodold s nssep-To% uemnb - az! IoDp 12 e uo!% uauI, u 01 À; gal s esolzequ el 'ionb s9idV' uemeuuozo eo Dap alns QI i no z0 uo!% enmroD ep% TnoiTo np n oelab sdm9u. amyem ua aqouajogp e-, 4enad II -auTmtanpdnIa I% euîej.ïe 9Inoo9 sdmaIl 9o cuamom ne 91 1nassaoo-docoTIm aI ed oualTogp a4.nad se7uuop ap i Ua; SuQI a 4TSUv 'T a, IV sTU; Iom 4q ^ al anb iuQAQ NVUAON QI suQp sa1o4, uaeTos aeIomEu rI suep saes! Iouiau sa; uuop sel anb -nod sasTid azl% uaAnnd suoi%! Sods! Psap 4e (9auasadae uou)

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Claims (22)

  1.- A method of controlling a heating / cooling system comprising a control device for operating a heating / cooling device and at least one battery thermostat intended to selectively activate and deactivate said control device as a function of measured temperatures and desired, the method comprising the steps consisting in monitoring the power level of a cell or cells which supply said thermostat, in emitting an alarm signal when the power level is below a predetermined value and, after a predetermined time after the emission of said alarm signal, has the thermostat deactivate the control device and keep it disabled.   2.- Method according to claim 1, wherein the thermostat is arranged to deactivate the control device and keep it deactivated after an extended period after the emission of said alarm signal.   3. A method according to claim 2, wherein said predetermined time is an extended period of several days.   4.- Method according to any one of the claims   1 to 3, in which said thermostat is furthermore made to keep the control device deactivated only if the power level has generally remained at said predetermined value or below it   during a second predetermined time.   5.- Method according to any one of the claims   1 to 4, further comprising the step of causing the alarm signal to initiate a timing sequence and for said thermostat to deactivate the controller upon completion of said timing sequence, unless levels of   higher power will be detected.   6.- Method according to any one of the claims   I to 5, further comprising the step of transferring data from a programmable memory of said thermostat to a non-volatile memory thereof, after a predetermined time after the emission of said alarm signal. 7.- Heating / cooling system comprising a control device for actuating a heating / cooling device and at least one battery thermostat intended to selectively activate and deactivate said control device as a function of measured and desired temperatures, said heating system / cooling further comprising a processing member means for monitoring the power level of a cell or batteries supplying said thermostat and emitting an alarm signal when the power level is lower than a predetermined value, said member means being arranged so as to cause said thermostat, after a predetermined time after the emission of said alarm signal, to deactivate said control device and keep it disabled.   8. A heating / cooling system according to claim 7, wherein said processing member means for monitoring the power level   is contained in said battery thermostat. 16 2726635   9. A heating / cooling system according to claim 7 or 8, wherein said processing member means is arranged to trigger a timing sequence to deactivate the control device after said predetermined period of time, unless higher power levels are detected by said organ means treatment.   10.- Heating / cooling system according to one   any of claims 7 to 9, wherein said   -thermostat comprises a programmable memory and a non-volatile memory, and in which said processing member means is arranged so as to cause, after a predetermined time after the emission of said alarm signal, the transfer of data from said   programmable memory to said non-volatile memory.   11.- Heating / cooling system according to one   any of claims 7 to 10, wherein the   control device is connected by cable to the thermostat or to each thermostat to be controlled by the latter, and said thermostat or each thermostat is provided with a latching relay intended to open or close at least one switch for activating or   deactivate the control device.   12.- Heating / cooling system according to one   any of claims 7 to 10, wherein a   switch or switches are provided in the controller, and the thermostat is arranged to produce output control signals for   establish the position of the switches.   13. A heating / cooling system according to claim 12, in which the thermostat and the control device are arranged so as to   communicate by transmitting and receiving means.   14.- Heating / cooling system according to one   any of claims 7 to 13, wherein said   heating / cooling system comprises a central heating system equipped with said control device for selectively actuating the heating device heating of this system.   15. A heating / cooling system according to claim 14, in which said control device is in the form of a programmer, and in which said thermostat is provided with means forming a processing member arranged so as to bring the thermostat to keep deactivated the programmer after a predetermined time after the emission of said alarm signal.   16.- Thermostat comprising a switching circuit intended to produce control signals to selectively activate and deactivate a controlled circuit, and a means forming a processing member for controlling the operation of said switching circuit, said thermostat being arranged so as to be supplied by one or more batteries and said processing member means being arranged to monitor the power level of the battery or batteries, to emit an alarm signal when the power falls below a predetermined level, and said processing member means being arranged to lock said switching circuit in a state where circuit deactivation control signals are produced, after a predetermined time after the emission of said alarm signal.  17. A thermostat according to claim 16, in which the switching circuit produces output signals to cause activation and deactivation. of the controlled circuit.   18. Thermostat according to claim 16 or 17, wherein said switching circuit is arranged so as to selectively adopt one of the two states, the first state being an activation state of the circuit and the   second state being a circuit deactivation state.   19. A thermostat according to claim 18, in which the switching circuit comprises a latching relay which is bistable and can take two states. 20.- Thermostat according to claim 19, wherein the processing member means is arranged so as to lock said switching circuit after an extended period after the emission of said alarm signal.   21. Thermostat according to claim 20, wherein said predetermined time is a period extended by several days.   22.- Thermostat according to any one of   claims 16 to 21, wherein said means forming   processing unit is required to lock said switching circuit only if the power level   generally remains at said predetermined value or   below it for a second predetermined time.