GB2245994A

GB2245994A - Time switch

Info

Publication number: GB2245994A
Application number: GB9108528A
Authority: GB
Inventors: Peter Bryce
Original assignee: SUNVIC CONTROLS Ltd
Current assignee: SUNVIC CONTROLS Ltd
Priority date: 1990-04-18
Filing date: 1991-04-18
Publication date: 1992-01-15
Also published as: GB9008651D0; GB9108528D0

Abstract

An electronic time switch, such as is used for central heating and hot water does not have any electrically powered display for set times or time of day. It has separate user operable buttons 27, 28, 30, 31 for turning on and off twice in 24 hours. During a first day the user operates these buttons at the intended turn on and turn off times. On subsequent days the time switch operates at the same times as on the first day, or at times which are shifted from these times by a preset amount. <IMAGE>

Description

CONTROLLER The present invention relates to an electronic time switch of a type generally referred to as a "controller" or "programmer". The time switch is intended to be suitable for the control of domestic central heating although it could also be applied for the control of other equipment.

Present day central heating controllers are often electronic devices having a display and various controls for operation by a user. The conventional manner of operation is that the user sets a real time clock within the device to the actual time of day and also then operates the controls to choose times of day at which the device will turn on and off a supply of electrical power to controlled apparatus. More elaborate devices may provide for different times of day on certain days of the week.

Time switches of this type are customarily run either from batteries or from the mains electricity supply. If the power supply is interrupted the record of times of day will be lost unless a back-up system typically battery or capacitor has been provided to back-up a mains supply and does not become exhausted during the period of interruption.

This may prove to be nothing more than an inconvenience.

However, if the user is away from home for a period of time during the winter, he or she may be relying on the time switch to turn on the heating at regular intervals in order to protect the heating system from possible frost damage.

According to one aspect of the present invention there is provided an electronic time switch, having one or more user-operable controls to start and stop the supply of electrical power to controlled apparatus at set times of day within a particular time cycle (typically 24 hours or 7 days), characterised in that the time switch is arranged to be operated by the user at a plurality of times within a time cycle and in subsequent repetitions of the time cycle automatically to start and stop the supply of electrical power to the controlled apparatus at times which are the same as or offset from the said times of operation by the user.

With this aspect of the present invention, the user does not need to set in advance the required on/off times for the output to the controlled apparatus but instead the time switch 'learns' in real time the user's requirement. This may be an "adaptive learning" procedure in which the times which are learned are derived, by means of an algorithm, from the actual times at which the user operates controls. Once a pattern has been stored the time switch repeats the pattern during subsequent time cycles.Typically after the first time cycle the user will have operated the controls to effect all the on/off operations in a time Cycle so in subsequent cycles the outputs will be controlled using the 'learned' times (which may reproduce directly or be derived from the times of operations in the first cycle.) An important feature is that there will exist implementations in which the user does not require feedback from the control i.e.

while a display for real time and stored times could be fitted, this is not generally required.

Typically, the time switch will be arranged so that the user can start and stop the output of power to controlled apparatus at least twice each during an initial period of 24 hours. The time switch will then start and stop the output of power to the controlled apparatus at the same times of day, possibly with predetermined modifications, during subsequent repetitions of the 24 hour period. Preferably, the time switch is provided with a user-operable override control enabling the user to turn on or off the output of power to the controlled apparatus on an individual occasion without altering the "learned" settings.

Preferably also the time switch enables the user to change the individual recorded settings. In order to allow change of individual recorded settings, the time switch is preferably arranged automatically to start and stop the supply of electrical power to the controlled apparatus at a plurality of respective times which are each the same as or offset from the most recent time of operation of a respective control in a preceding time cycle.

A time switch according to this aspect of the invention can have the advantage that programming by the user does not require planning in advance.

A further advantage is that there is no requirement for the user to set the time of day. Also, there is no necessity for the switch to be provided with any form of electrically powered (or other) numeric display for the times of day or set times. A display of some kind may optionally be provided: however, omission of a powered display provides a saving in manufacturing costs and can also serve to reduce the size of the time switch. Consequently, certain forms of this invention are such that the time switch does not have any electrically powered display for times of day or set times.

It may be desired to provide the facility for an operator to set more than one time at a single occasion. This can be accomplished by providing means which will enable the operator to vary the amount by which an automatic turn on or turn off action is offset from an actual time of operation by the user.

In a further aspect of this invention, which may be an alternative or used in addition, an electronic time switch suitable for control of domestic central heating, is constructed and arranged such that on restoration of electrical supply after a period of interruption sufficient to cause loss of recorded information, the time switch automatically effects supply of power to the controlled apparatus for predetermined periods of time at predetermined intervals. Such an arrangement can be useful to ensure that some protection against frost is maintained even if interruption of the electrical supply causes loss of recorded on and off times. Preferably the time switch can be arranged so that on restoration of electrical supply it automatically effects supply of power to the controlled apparatus at least once in any period of 24 hours.Preferably it effects the supply of power for periods of at least 2 minutes but not more than 3 hours at intervals of not more than 12 hours. Preferably both aspects of the invention are provided together in a single time switch, but either can be used without the other.

Embodiments of this invention will now be described in more detail, by way of example, with reference to the accompanying drawings in which: Fig. 1 illustrates the front panel of a time switch, with its cover omitted; Fig. 2 illustrates the same time switch with its cover closed; Fig. 3 illustrates the front panel of a second form of time switch, with its cover open; Fig. 4 shows a schematic diagram applicable to either of the time switches.

Referring first to Fig. 4, either of these time switches can be constructed to use a mains electricity supply (as is illustrated) and may optionally include a back-up system. A power supply unit 10 within the device converts the mains supply to a low voltage DC supply, for logic circuitry 12 which incorporates volatile and non-volatile memory and a real time clock.

The logic circuitry causes the operation of an output switching arrangement 14 whose operation controls the supply of voltage at output connections which in use are connected to the controlled apparatus.

Electrical connection of the time switch's output connections to heating equipment can be any conventional manner of connection as customarily used with a time switch or programmer.

The embodiments of time switch shown in the drawings are constructed to provide two "on" periods during every 24 hours.

The use of logic circuitry to control output connections is conventional. The output circuitry may well include one or more relays energised by the logic circuitry, but other forms of operation are possible such as a triac or a bimetallic element heated by a resistor powered by the logic circuitry.

Referring now to Fig. 1, according to the setting of a three - position switch 22 on the front panel, the circuitry enables both, one only or neither of the outputs during any "on" period. More specifically, if the switch 22 is set to the top position marked "HW CH" both hot water (HW) and central heating (CH) output connections are enabled together during an "on" period.

These connections are connected to a central heating boiler and/or one or more motorised control valves and/or one or more thermostats so that a hot water tank and radiators are heated together. If the switch 22 is set to the mid position marked "HW" only the hot water output connection(s) is enabled during an "on" period so that voltage is connected to the heating equipment in such a way as to heat the hot water tank but not the radiators. If the switch 22 is at the bottom position neither output is enabled and the heating equipment does not function during the "on" periods. The switch 22 could be an input to the logic circuitry 12 or a switch handling voltage from the output circuitry 14.

The present invention departs from previous conventional practice, in the organisation of the logic circuitry and some of the controls connected to it. As shown by Fig. 1 the device has the switch 22 already mentioned, a pair of indicators 24,35 and six push buttons, 27,28,30,31,33 and 34.

The button 27 is used to start one period of operation and button 28 is used to terminate it. The button 30 starts the second period of operation within any 24 hours and the button 31 terminates it.

To operate the time switch a user would typically set switch 22 to select CH + HW. The user would then operate the push buttons (27,28,30,31) to turn the heating on and off at the desired times during the first period of 24 hours. For instance, on getting up at 7.00am the user would press button 27. On leaving for work at 8.30am the user would press button 28. On returning from work at 5.00pm the user would press button 30 and on going to bed at 10.30pm the user would press button 31.

The logic circuitry is arranged to record these times with reference to its real time clock. There is no necessity to set this real time clock. In the case of the "turn on" times the logic circuitry records the times as half an hour earlier than the times at which the buttons 27 and 30 were actually pressed. On subsequent days the user does not need to operate any of the buttons. The time switch will turn the heating on from 6.30am to 8.30am (so that the heating is turned on half an hour before the user gets up) and from 4.30pm to 10.30pm (so that the heating comes on half an hour before the user returns home from work). The indicator 24 is enabled by the logic circuitry when the HW output is enabled, and is also enabled if the CH output is enabled together with the HW output. This indicator could be a lamp or an LED.

If on any day the user wishes to switch from an "off" to "on" state or vice versa without altering the recorded times, the user presses the button 33 labelled "override". This reverses the state of the output circuitry temporarily but has no effect on subsequent "on" and "off" periods.

If the user presses button 34 labelled "+hours" it gives a temporary additional "on" period of a fixed length such as one hour for one occasion only. This, like the "override" button 33, is a conventional feature which allows a user to alter what is happening on one day without altering the recorded settings. The indicator 35 is lit while during a period when output is enabled because normal operation has been overridden or during a time when button 34 has been used to extend an "on" period.

Any recorded time can be changed by pressing the appropriate button at the new desired time. For example if the evening "on" period starts at 4.30pm and the user wishes to change it, pressing the button at 6pm will cause the heating to come on at 5.30pm in place of 4.30pm. (The half hour offset is explained above). A consequence of this function is that if the user does not record all four times during an initial cycle of 24 hours, any missing times can be recorded on subsequent days.

If the user wishes not to have any morning "on" period the two buttons 27,28 are pressed simultaneously, which causes the recorded morning times to be deleted. New times can then be recorded (later or straight away) by operating those two buttons at the desired times of day. The evening "on" period can similarly be omitted entirely by pressing the buttons 30,31 together. New times can be recorded by operating these buttons at the desired times.

The time switch also allows a user to pre-set times which are not actual times of operation but are offset from these times. This might be used by an installer to set switching times to suit individual user's requirements without the need to be present at the actual switching times.

If any of the buttons 27,28,30,31 is held pressed in and then the "override" button 33 is pressed the time which is recorded will be moved back from the actual time by one hour. If the "override" button is pressed more than once, the recorded time moves back one hour for each press on the override button. In the same way recorded times can be moved forward from actual times by pressing the "+hours" button 34 while a button 27,28,30 or 31 is held pressed.

For example, at 11.OOam button 27 is pressed in and held while the "override" button 33 is pressed four times. Then button 28 is held pressed in while button 33 is pressed twice. This sets morning "on" and "off" times of 7.00am and 9.00am. Next button 30 is held pressed while button 34 is pressed five times. Finally button 31 is held pressed while button 34 is pressed ten times. This sets an evening "on" and "off" times of 4.00pm and 9.00pm.

The time switch is provided with a cover 48 (omitted from Fig. 1) which includes an opening 49. It is attached by hinges 50 at the base of the front panel. When the cover is closed, as shown in Fig. 2 the push buttons 27,28,30,31 are concealed to prevent inadvertent operation of them, but the buttons 33,34 and the switch 22 are exposed and operate through the opening 49.

The time switch shown in Fig. 3 is similar in many respects to that shown in Figs. 1 and 2. It is shown with its cover 48 open. This time switch has the six push buttons 27,28,30,31,33,34 and indicators 24 and 35 whose functions are exactly as described previously.

In place of the three position switch, there are three individual push buttons 40,41,42. If the middle button 40 is pushed in then only the HW output is enabled during any "on" period. If the top button 41 is pushed in both HW and CH outputs are enabled during an "on" period. If button 42 is pushed in, neither output is enabled.

This time switch has four indicator dials 43 to 46 mounted on the inside of the cover 48. Each dial consists of a simple representation of a clock face together with a single hand 47 which is pivotally mounted to the centre of the dial with sufficient friction that it will remain in any position to which it is pushed. The hands 47 are not connected to any internal parts of the time switch. Instead they can be adjusted by the user to indicate the times at which he or she pushed the buttons 27 to 31 and thereafter serve as a reminder of the times of day to which the time switch is currently set. Other implementations of this simple reminder feature may also be used.

Another possibility is to provide an area on the inside of the cover 48 where the recorded times can be written by hand, using a pen with water-washable ink.

Both of the time switches shown can optionally have an automatic frost protection feature in accordance with the second aspect of this invention, incorporated into their logic circuitry. In the event that the mains electricity supply is interrupted, the real time clock ceases to function and the times of day which have been stored as a result of the user operating the push buttons are lost from the memory of the logic circuitry.

When the electricity supply is restored the logic circuitry goes into an initial default state. It enables both outputs for a period of 30 minutes. Then it repeats this at six hour intervals indefinitely until such time as the user presses any of the buttons.

Once the user does this the time switch again records the times at which the buttons 27,28,30,31 are pressed typically during a first cycle of 24 hours and controls the outputs as described previously.

While the time switch is in the frost protection mode it causes the indicators 24,26 to flash at regular intervals so as to warn the user that there has been an interruption of electricity supply and that the heating system is no longer functioning at the pre-set on and off times.

The logic circuitry will conveniently consist of a micro processor with a read only memory, a small amount of random access memory, an input output port connected to the user-operable buttons and drivers for energising the indicator lamps and the relays.

Variations from the embodiments described above are possible within the present invention. In particular, the indicators could take any convenient form including flags, mechanically attached to the switch 22 so as to be moved on operation of that switch. Such mechanical flags could possibly be arranged to move in front of indicator lamps or LED's enabled by the logic circuitry. Another possibility is the provision of audio feedback, that is to say an audible signal is given when a button is pressed by the user. Another possibility is that the automatic frost protection mode would not operate if the switch 22 was set to the "off" position.

Another way in which feedback might be given to the user would be for the indicator(s) to change temporarily when a button is pressed e.g. to flash on briefly if not lit, or to flash off briefly if already lit.

The embodiments described above are employed for the control of central heating and hot water but a time switch in accordance with this invention could be used for other purposes such as the control of combination boiler systems or other equipment where the "learning" principle is appropriate.

The embodiments described above are intended to provide a twenty four hour time cycle during which initial learning occurs and which is then repeated.

The same principle could be adopted with a seven day cycle or any other time cycle which might be desired.

Claims

1. An electronic time switch, having one or more user-operable controls to start and stop the supply of electrical power to controlled apparatus at set times of day within a particular time cycle, characterised in that the time switch is arranged to be operated by the user at a plurality of times within a time cycle and in subsequent repetitions of the time cycle automatically to start and stop the supply of electrical power to the controlled apparatus at times which are the same as or offset from the said times of operation by the user.

2. A time switch according to claim 1 having at least one user-operable control to start the output of power and at least one user-operable control to stop the output of power.

3. A time switch according to claim 1 having at least two user-operable controls to start the output of power at respective times in a time cycle and at least two user-operable controls to stop the output of power at respective times in a time cycle.

4. A time switch according to any one of the precedings claims arranged automatically to start and stop the supply of electrical power to the controlled apparatus at a plurality of respective times which are each the same as or offset from the most recent time of operation of a respective control in a preceding time cycle.

5. A time switch according to any one of the preceding claims having a user-operable control to override automatic operations in a chosen time cycle without altering times of operation in subsequent time cycles.

6. A time switch according to any one of the preceding claims which does not have any electrically powered display of time.

7. A time switch according to any one of the preceding claims which is operable such that on restoration of electrical supply after a period of interruption sufficient to cause loss of recorded information, the time switch automatically effects supply of power to the controlled apparatus for predetermined periods of time at predetermined intervals.

8. A time switch according to any one of the preceding claims which incorporates means whereby stored start and stop times can be set to times offset by predetermined amounts relative to the current time of day.

9. A time switch substantially as herein described with reference to the accompanying drawings.