GB2121536A

GB2121536A - Programmable controller

Info

Publication number: GB2121536A
Application number: GB08315316A
Authority: GB
Inventors: Brian Carter
Original assignee: AIRELEC IND
Current assignee: AIRELEC IND
Priority date: 1982-06-04
Filing date: 1983-06-03
Publication date: 1983-12-21
Also published as: FR2528190A1; FR2528190B1; GB8315316D0

Abstract

A programmable controller, for central heating systems for example, has an optical input (LED 3) and an optical output (Sensor 11) on a common axis 2, which are connected via an off-axis observation point where the optical path intersects a programme member 5. The latter can be made selectively opaque and transparent as required, and is rotatable about the axis 2 relative to the observation point; as described the optic fibre 9 feeding sensor 11, together with a fibre 10 giving a visible display of the state of the controller, is rotated, either by a clock for a timer, or by an ammeter for a delesteur (selectively disconnects low priority devices if total load exceeds a threshold). Also described is a thermostat where a mirror on a laminated strip does or does not reflect light from an input optical fibre to an output fibre. Timer, delesteur and thermostat may be connected optically in series, have a single input light source and single output sensor. <IMAGE>

Description

via fibre 9 to a light-sensor 11 and is also directed via fibre 10 to a translucent screen 12. Fibres 9 and 10 are mounted in a block 13 which is rotated about axis 2 by a clock mechanism 14.

It will be seen that generally there is an optical coupling path from the input LED 3 to the output photo-sensor 11. The optical coupling is effected via a rotating "window" represented by the ends of fibres 9 and 10.

Plate 5 is best seen from Figure 2 and comprises a translucent annulus 15 which may be selectively blocked out by adhesive stockers or by marking with pencil or pen, for example. Thus, selected parts can be made opaque. When the rotating "window" is adjacent a translucent part of annulus 15, light is transmitted and the photo-sensor responds. On the other hand, when the "window" is adjacent a blocked-out part of the annulus, light is cut off. In this way the device can easily be programmed to switch on and off at required times by marking the programme plate 5, which is readily removable from body 1.

The light visible via fibre 10 gives an indication when the controller has switched on.

Referring now to Figure 3 there is shown a "delesteur" in accordance with the invention. Again, the device has a generally cylindrical body. In this example, however, the movement is effected not by a clock but by an ammeter 20. The ammeter moves block 13 which carries an input optical fibre 21. The fibre 21 is coupled to a fibre 22 which transmits light from a remote source (not shown). Light is received via the observation region by a collecting mirror system similar to the transmitting mirror system of Figure 1 and is fed to an output fibre 23 to illuminate a remote sensor (not shown).

In this case the programme card is shown in Figure 4 and has an arcuate region 24 which can be marked so as to ensure that light is blocked off to effect controlled switching when the measured current reaches a predetermined value, which can be changed.

Figure 5 illustrates a comprehensive control system embodying the invention. Two electric heaters 30,31 are illustrated. Each is connected by a power cable to a control switch 32, 33 respectively. The control switches are optically sensitive to inputs at 34 and 35 conveyed by optical fibres 36, 37. Input power to the control switches is derived from the mains through a current-limited cut-off switch 38.

The total input current to the domestic installation is metered by an ammeter 39. Current for the heaters is via a line 40. Current for the remainder of the domestic supply (of higher priority than the heaters) is taken from line 41.

The heating system comprises a time-controller 42 of the general kind shown in Figure 1. However, while the controller has an LED light source 43, it has no light-detector, but instead transmits light to a "delesteur" 44 of the kind shown in Figure 3. The ammeter 39 is the movement device of the delesteur and light is transmitted from the output of the delesteurto a divider 45. Light from the divider 45 is transmitted by optical fibres 46, 47 to respective thermostats 48, 49 which control the heaters 30,31.

The thermostats are described below with reference to Figure 6. Light from the thermostats is transmi'tted over fibres 50, 51 to the respective control switches 32, 33.

In this way light is received by, say, control switch 32 to switch on the heater if (a) the time-controller is on and (b) if the delesteur indicates that the total current is within the prescribed limit and (c) if the respective thermostat indicates a "too cool" temperature. Otherwise the heater is switched off because no light is received by switch 32.

If the delesteur shows an over-current, the heaters will be switched off, to allow current to be continued to be supplied on line 40 without triggering the cut-off switch 38.

It will be seen that with this arrangement the only electrical wiring required is for the power cables. The control signals are carried by the relatively inconspicuous optical fibres.

Referring now to Figure 6 there is shown schematically one of the thermostats of Figure 5. Light from the input optical fibre 46 is reflected by a mirror 54 to the output fibre 50. Mirror 54 is mounted on a bi-metal strip which bends as the room temperature changes. The reflected light level is thus cut off beiow a critical level if the temperature rises too much. An adjustable stop 55 limits the movement of the mirror to set the cut-off temperature.

1. A programmable controller comprising a housing having a control axis; an optical input at the axis; an optical output at the axis; an observation region radially spaced from the axis; means for optically coupling the input with output at the observation region; a programme member optically interposed between the input and the output at the observation region, the programme member being capable of being made transparent and opaque selectively in accordance with a required programme; and a movement which effects relative rotation about the axis of the observation region with respect to the programme member.

2. A programmable controller as claimed in claim 1 wherein the observation region is defined by a window associated by optical coupling with the input or with the output.

3. A programmable controller as claimed in claim 2 wherein the said window is the pick-up or emission end of an optical fibre.

4. A programmable controller as claimed in claim 2 or claim 3 wherein, in use, the window is turned relative to the programme member by rotating the programme member or by rotating the member which defines the window.

5. A programmable controller as claimed in claim 4 which is a time controller, the said movement being generated by a clock.

6. A programmable controller as claimed in claim 4 which is a delesteur, the said movement being generated by an ammeter.

7. A programmable controller as claimed in any of the preceding claims wherein the optical input is a pick-up for light from an external light source and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. via fibre 9 to a light-sensor 11 and is also directed via fibre 10 to a translucent screen 12. Fibres 9 and 10 are mounted in a block 13 which is rotated about axis 2 by a clock mechanism 14. It will be seen that generally there is an optical coupling path from the input LED 3 to the output photo-sensor 11. The optical coupling is effected via a rotating "window" represented by the ends of fibres 9 and 10. Plate 5 is best seen from Figure 2 and comprises a translucent annulus 15 which may be selectively blocked out by adhesive stockers or by marking with pencil or pen, for example. Thus, selected parts can be made opaque. When the rotating "window" is adjacent a translucent part of annulus 15, light is transmitted and the photo-sensor responds. On the other hand, when the "window" is adjacent a blocked-out part of the annulus, light is cut off. In this way the device can easily be programmed to switch on and off at required times by marking the programme plate 5, which is readily removable from body 1. The light visible via fibre 10 gives an indication when the controller has switched on. Referring now to Figure 3 there is shown a "delesteur" in accordance with the invention. Again, the device has a generally cylindrical body. In this example, however, the movement is effected not by a clock but by an ammeter 20. The ammeter moves block 13 which carries an input optical fibre 21. The fibre 21 is coupled to a fibre 22 which transmits light from a remote source (not shown). Light is received via the observation region by a collecting mirror system similar to the transmitting mirror system of Figure 1 and is fed to an output fibre 23 to illuminate a remote sensor (not shown). In this case the programme card is shown in Figure 4 and has an arcuate region 24 which can be marked so as to ensure that light is blocked off to effect controlled switching when the measured current reaches a predetermined value, which can be changed. Figure 5 illustrates a comprehensive control system embodying the invention. Two electric heaters 30,31 are illustrated. Each is connected by a power cable to a control switch 32, 33 respectively. The control switches are optically sensitive to inputs at 34 and 35 conveyed by optical fibres 36, 37. Input power to the control switches is derived from the mains through a current-limited cut-off switch 38. The total input current to the domestic installation is metered by an ammeter 39. Current for the heaters is via a line 40. Current for the remainder of the domestic supply (of higher priority than the heaters) is taken from line 41. The heating system comprises a time-controller 42 of the general kind shown in Figure 1. However, while the controller has an LED light source 43, it has no light-detector, but instead transmits light to a "delesteur" 44 of the kind shown in Figure 3. The ammeter 39 is the movement device of the delesteur and light is transmitted from the output of the delesteurto a divider 45. Light from the divider 45 is transmitted by optical fibres 46, 47 to respective thermostats 48, 49 which control the heaters 30,31. The thermostats are described below with reference to Figure 6. Light from the thermostats is transmi'tted over fibres 50, 51 to the respective control switches 32, 33. In this way light is received by, say, control switch 32 to switch on the heater if (a) the time-controller is on and (b) if the delesteur indicates that the total current is within the prescribed limit and (c) if the respective thermostat indicates a "too cool" temperature. Otherwise the heater is switched off because no light is received by switch 32. If the delesteur shows an over-current, the heaters will be switched off, to allow current to be continued to be supplied on line 40 without triggering the cut-off switch 38. It will be seen that with this arrangement the only electrical wiring required is for the power cables. The control signals are carried by the relatively inconspicuous optical fibres. Referring now to Figure 6 there is shown schematically one of the thermostats of Figure 5. Light from the input optical fibre 46 is reflected by a mirror 54 to the output fibre 50. Mirror 54 is mounted on a bi-metal strip which bends as the room temperature changes. The reflected light level is thus cut off beiow a critical level if the temperature rises too much. An adjustable stop 55 limits the movement of the mirror to set the cut-off temperature. CLAIMS

7. A programmable controller as claimed in any of the preceding claims wherein the optical input is a pick-up for light from an external light source and SPECIFICATION Programmable controller The invention relates to a programmable controller for controlling electrical functions. Particular application for the invention is found in a time-controller for an electric heating system and in a limit controller for maintaining electrical power consumption within a prescribed limit.

Time controls for heating systems generally have the facility for switching the central heating on twice and off twice at preset times during the day. Such presetting is generally accomplished by setting the positions of slides which determine the positions at which respective micro-switches will be operated by a clock-driven cam. The provision of four slides and micro-switches means that either that the controller is large and cumbersome or that the slides are small and difficult to set. Also, it is difficult to ensure that the slide positions are easy to read and that the programming operation is simple to understand.

Another type of controller is used to limit the electric current taken by an installation. In some electrical distribution systems, and that of France is one example, the tarrif for electric power can be set in accordance with the total power consumption of an installation, and an automatic limiter is installed to ensure that the required power consumption limit is not exceeded. In the event that the limit is exceeded, the limiter will cut off all power, until some appliances are switched off, whereupon the limiter can be reset. This procedure is inconvenient and accordingly there is a requirement for a "delesteur" which will respond to power consumption, or in practice current amplitude, and selectively switch off non-priority appliances, such as heaters, if the limit is approached. Such a delesteur requires a programming facility to allow the limit to be set.

The present invention provides a programmable controller which offers advantages of simplicity and ease of comprehension, and which also allows a comprehensive control system to be built up with the minimum of complication.

According to one aspect of the invention a programmable controller comprises a housing having a control axis; an optical input at the axis; an optical output at the axis; an observation region radially spaced from the axis; means for optically coupling the input with output at the observation region; a programme member optically interposed between the input and the output at the observation region, the programme member being capable of being made transparent and opaque selectively in accordance with a required programme; and a movement which effects relative rotation about the axis of the observation region with respect to the programme member.

The observation region may be defined by a window associated by optical coupling with the input or with the output. Conveniently, the "window" is the pick-up or emission end of an optical fibre. The "window" may be turned relative to the programme member by rotating the programme member or by rotating the memberwhich defines the window - e.g. the optical fibre.

The movement may be generated by a clock in the case of a time controller or by an ammeter in the case of a "delesteur".

The optical input may be a light source, for example a lamp or light-emitting diode, powered electrically. Alternatively, it may be a pick-up for light from an external light source, perhaps coupled by optical fibres.

The optical output may be a photo-detector, for example a light-sensitive transistor arrangement electrically connected to a controlling circuit. Alternatively, it may be an optical coupling to further devices, perhaps coupled by optical fibres.

It will be seen, therefore, that the controller in accordance with the invention may have an electrical or optical input and it may have an electrical or optical output.

The use of a controller with a totally optical input and output allows the development of a total optical control system and this has advantages in a heating installation, for example.

Optical fibres can now be obtained in appreciable lengths and in comparison with conventional electric wires for connection to time-controllers, delesteurs and thermostats, they are thin and inconspicuous.

Optical fibres are therefore particularly suitable for coupling in domestic heating installations.

According to another aspect of the invention there is provided a heating installation which comprises a light-sensitive control arrangement in combination with one or more thermostats, the or each thermostat being a device which transmits or obstructs iight-passing from an input to an output in accordance with temperature, and the system including optical fibres which effect coupling between the or each thermostat and the control arrangement.

Preferably the control arrangement includes a programmable controller as described above. The controller may be a time-controller optically coupled to a "delesteur" also in accordance with the invention.

The invention will further be described with reference to the accompanying drawings, of which: Figure 1 is a cross-sectional elevation of a timecontroller in accordance with the invention; Figure 2 is a perspective view of the programme member of the controller of Figure 1; Figure 3 is a cross-sectional view of a "delesteur" in accordance with the invention; Figure 4 is a perspective view of the programme member of the "delesteur" of Figure 3; Figure 5 is a schematic circuit diagram of a heating system in accordance with the invention; and Figure 6 is a diagram of one of the thermostats of the system of Figure 5.

Referring to Figure 1 there is shown a timecontroller having a generally cylindrical body 1 with an axis 2. A light-emitting diode 3 is situated on the axis and emits light which is reflected from a domed mirror 4 on a programme piate 5 to an annular mirror strip 6. Light from the strip 6 is received through a transparent annulus 8 buy a pair of optical fibres 9, 10. The receiving ends of the fibres define a window, or observation region. Light is transmitted the optical output is an optical coupling forfurther optical devices.

8. A heating installation comprising a lightsensitive control arrangement in combination with one or more thermostats, the or each thermostat being a device which transmits or obstructs lightpassing from an input to an output in accordance with temperature, and the system including optical fibres which effect coupling between the or each thermostat and the control arrangement.

9. A heating installation as claimed in claim 8 including a programmable controller as claimed in any of claims 1 to 7.

10. A programmable controller substantially as hereinbefore described with reference to Figures 1 and 2 or 3 and 4 of the accompanying drawings.

11. A heating installation substantially as hereinbefore described with reference to Figures 5 and 6 of the accompanying drawings.