GB2203874A

GB2203874A - Control system

Info

Publication number: GB2203874A
Application number: GB08804331A
Authority: GB
Inventors: David Gemmell; Duncan Anthony Irvine
Original assignee: Possum Controls Ltd
Current assignee: Possum Controls Ltd
Priority date: 1987-04-07
Filing date: 1988-02-24
Publication date: 1988-10-26
Anticipated expiration: 2008-02-24
Also published as: GB2203873A; GB2203873B; GB2203874B; GB8804331D0; GB8708314D0

Abstract

A control system has two input stations 11, 12 for a disabled user, a control unit 17 containing a microprocessor and memory with control programs, and a plurality of controlled switching devices 22 each of which controls the operation of a domestic appliance such as an electric fire, lamp, radio or television. Each input station 11, 12 has a specially adapted input device 13 to be used by the disabled user in conjunction with a display on the screen 23 of an associated monitor 15. The display provides a scanning system that allows the disabled user to selectively control the devices 22 with the input device 13. Each switching device 22 also has a manually operable push button 27 and the control unit detects actuation of the push button 27 and in response causes the switching device 22 to change the state of the associated appliance from ON to OFF or vice versa. <IMAGE>

Description

2203874 CONTROL SYSTEM This invention relates to a control system for use

by a disabled person and an attendant able-bodied person.

For many years there have been available for severely physically disabled persons equipments known as environmental control systems in which a display provides the user with an indication of which one of a plurality of domestic appliances, for example a radio, an electric fire, a television, a telephone, a page turner and an alarm, is in operation under the control of the control system. Such-a system may have input means in the form of one or two on/off switches, possibly adapted to be controlled by sucking and/or blowing by the user, the operations of the switch or switches being automatically responded to by the system to provide the user with a method of initiating, controlling and terminating a scanning of the display positions of the display. Examples of such equipment used in the United Kingdom are the environmental control systems known respectively as the PSUI and PSU3 manufactured by Possum Controls Limited. A micro-processor based environmental control system is-described in patent specification GB 2137001.

All of the apparatus mentioned specifically hereinbefore makes use of a display panel or area in which individual parts are illuminated by discrete light sources. A microprocessor-based word processor adapted for use by severely physically disabled persons has also been produced, under the name WOMBAT, manufactured by Possum Control Limited, which utilizes a domestic television set for displaying words, phrases and complete texts. However, to control the operation of the WOMBAT, a separate display panel with selectable light sources is required. In our patent application no.

87 08314 there is described an environmental control system which can be actuated by a disabled person from a plurality of input stations each having a respective set of controlled outputs of the system associated therewith and having a controlled display which presents information on a television-type screen.

The system has a microprocessor-based control unit which includes EPROM stored programs for controlling two or more input 2 stations, loudspeaking telephones, and a plurality of switching devices included on a serial link with the input stations. Each input station has a television type monitor on the screen of which, when an input switching device operable by a disabled person is actuatedi a main menu is presented in the form of a list of those of the switching devices and the telephones which can be controlled from that input station. By use of the input switching device and the menu dislay, a switching device or the telephone can be selected for control. If control involves more than switching power on or off to an appliance, a new menu appears listing the various functions to be chosen, e.g. television channel, volume control.

Each controlled switching device has one or more relays having controlled switch contacts to be connected in the power supply lines to the controlled appliance and, if necessary, to means for adjusting some function of the controlled appliance, such as television channel, sound volume, and so forth.

Switching relays were, and are, used in switching devices controlled by the control units of PSUI and PSU3 systems for the same purpose.

Each such swi tching device has a three pin mains input plug to be inserted into a domestic or hospital mains output socket, and has a mains power output socket into which'the mains plug of the controlled appliance is inserted.

It has been found that, in a domestic environment, when the disabled user is no longer in a particular room containing say a television, an electric fire and a table lamp, all of which are connected to a control system used by the disabled person when in that room, an able-bodied attendant wishing to use these appliances will unplug them from the control system and plug them directly into the domestic mains output sockets. A result of this action is sometimes that the able-bodied attendant forgets to unplug the appliances from the domestic mains output sockets, re-plug them into the switching devices, and plug the switching devices into the domestic mains output sockets before the disabled user returns to the room. Although such an occurrence can easily be dealt with if the attendant is still present when the user wishes to control the uncoupled appliances, there may be no attendant present when the 3 user wishes to have control, so that there may be inadequate heat or light, or no entertainment in the room.

it is therefore an object of the present invention to provide, in a control system for use by a disabled person, means which allow an able-bodied attendant to share with a disabled user control of at least one control function of the system without the able-bodied attendant having to utilize an input adapted for use by a disabled person, or to disconnect a controlled appliance from the system.

Preferably, the means according to the invention is in the form of a manually operable push button switch incorporated in a controlled switching device of the system, the state of this push button switch being sensed by a control unit of the system and the control unit changing the state of the switching device in response to each actuation of the push button switch, so that when an appliance is coupled to that switching device, the state of the appliance is changed at each actuation of the push button switch.

The control system preferably, of course, indicates such changes of state so that when a disabled user reassumes command of the system, or that portion of the system which includes the push button switch, the current state of the appliance is immediately apparent to him or her, and can be ch anged, if desired, to the other state through the operation of.an input adapted for use by the disabled user.

The various aspects of the present invention are defined hereinafter by the claims, to which reference should now be made.

The invention will now be described in more detail, solely by way of example, with reference to the accompanying drawings,in which:- Fig. 1 is a block diagram of microprocessor-based environmental control and communicator apparatus embodying the invention; Figs. 2 and 3 are illustrations of displays which may be presented by the apparatus of Fig. 1; Fig. 4 is a circuit diagram of part of a controlled switching device of the apparatus of Fig. 1,i and Fig. 5 is a circuit diagram of a further part of the controlled switching device of Fig. 4.

Fig. 1 is a block diagram of a control apparatus embodying the invention and having two input stations 11 and 12. Each input 4 station has an input switching device 13 operable by a severely physically disabled person, a switching and junction unit 14 which houses a battery (not shown) and power supply and battery charging circuitry (not shown), a television-type monitor unit 15, and a master intercom unit 16. The input stations 11 and 12 are situated in different rooms and are both coupled to a control unit 17 which includes a microprocessor (not shown) and associated processing and storage circuitry (not shown).

The control unit 17 is also coupled, through an LST9 controller 20, which is a telephone control apparatus approved by British Telecom, to two loudspeaking telephone sets 18 and 19 sited respectively in the rooms in which the input stations 11 and 12 are located.

A serial bus 21 connects the control unit 17 to controlled switching devices 22 in the rooms containing the stations 11 and 12 through the respective switching and junction units 14. The switching devices 22 may control simple on/off appliances such as electric fires and lamps, and groups of functions of more complex appliances such as television sets, radio sets, and controlled beds.

Each switching device 22 is provided with encoding switches which give it an identifiable address code so that the control unit 17, by poling the devices 22 in sequence, can determine which devices are present. The switching and function units 14 are also provided with coding means which enable the control unit 17 to determine which input station ks being used.

The coding means of a switching and junction unit 14 includes encoding switches which give it an identifiable address code, and means for indicating by a status signal the status of the input switching device 13 connected to the unit 14, i.e. whether or not the device 13 is being actuated. The status signal may be simply a single bit which is 0 whenever the switching device 13 is not actuated and I whenever the device 13 is actuated.

The address code of each switching device 22 includes two bits which associate the particular device 22 with the input station 11 or 12 sited in the same room as that device 22. Thus the control unit 17 is able to address commands specifically to only those devices 22 which are in the room containing the input station 11 or 12 which is in use, since the command signals can include the room identity in the form of the two bits of the address code of the device 22 which is to be controlled, and the devices 22 can be provided with a comparison circuit or gating circuit which ensures that only the intended device 22 responds to the command signal.

The control unit 17 is also adapted to actuate only the monitor unit 15 of whichever input station 11 or 12 it detects as having an actuated input switching device 13 first after a predetermined length of time in which no input station has presented an actuated input switching device 13. This prevents more than one input station being used at the same time, and reduces the risk of accidental disabling of the input station currently in use. The monitor unit 15 of the last used input station remains activated unless a changeover to another input station occurs through the use of the input switching device 13 of that other input station after the predetermined length of time.

The single LST unit 20 shown is actuated whichever input station11 or 12 is used to control the telephone system. kowever, the speaker/microphone units 18 and 19 are switched into or out of operation as required. Under present British Telecom regulations this switching must be done manually by a helper. However, it is possible as a practical matter to effect the switching under the control of the active input station and the control unit 17 if respective switching devices 22 of the serial link 21 are used to control coupling of the speaker/microphone units 18 and 19 to the LST unit 20. Alternatively, to comply with present British Telecom regulations, more than one LST unit, one for each speaker/microphone unit in the system, may be used and controlled directly from the control unit 17.

When the control unit 17 senses that one of the input stations is in use, for example, station 11, as a result of operation of the input switching device 13, the monitor unit 15 of that station is energised and caused to present initially a main menu on its screen 23. An example of a main menu is illustrated in Fig. 2. This main menu has two wide columns of eight rectangular row areas. A blank area remains on the screen below this menu to provide space for a variety of messages which may be displayed from different sources.

9 By colour, the top row area of the left hand column is indicated as being active. For example, the active state may be an orange background, the other row areas of both columns having a green' background. By operating the input switching device 13, the user can cause the active background colour to scan down the row areas of the left hand column and then up the row areas of the right hand column. To select for operation the device or function indicated in any row area of a column, the input switching device 13 is operated while the particular row area of a column is showing the active background colour. The row area of a single column will now be referred to as a cell. For example, to cause an audible and visible alarm to be activated, the user initiates the scanning operation and selects the cell with the word ALARM displayed. If the telephone rings, the SEIZE LINE cell is selected by the user if he wishes to receive the call. The foreground colour, i.e. colour of the lettering, in the active cell may also differ from the foreground colour in other cells and be controlled in the same way as the active background colour.

A detailed description of the manner in which the operation of an input switching device such as the device 13 is related to selection of a displayed function or device and control of the selected function or device is given in patent specification GB

2137001 to which reference should be made for such information.

When a device or set of devices or functions is selected on the main menu and requires, for proper operation, further choices by the user, selection of the appropriate cell of the main menu results in replacement of the main menu by a special menu relating to the selected cell.

Fig. 3 illustrates the special menu called up by selection of SOCKETS #1 on the main menu (Fig. 2).

SOCKETS #1 allows selection of a fan, a heater, a lamp, an electric blanket, and three further electrically controllable devices powered respectively through controlled sockets 05, 06 and 07. A detailed description of other menus and the associated functions is included in patent application no. 87 08314 The space on screen below the currently displayed menu is used to display messages such as:- 1. Status information, ie. what appliances are in operation, e.g. electric fire, electric blanket, television, tape recorder, electrically-controlled curtains, etc.

2. System prompts, e.g. which intercom is operating, which telephone repertory store is being dialled out and a connection made.

3. Error diagnostic messages from the system for assisting service engineers if the system develops a fault.

The apparatus of Fig. 1 uses a single microprocessor as its central processing unit. This microprocessor is, in a constructed example of the apparatus, a Zilog Z-80 microprocessor, and has an 8 bit data bus and a 16-bit address bus connected to it. A memory map showing the principal divisions of the 64K memory space addressable by the address bus is described in patent application no. 87 08314.

At the beginning of the scan program, a loop is run in which the output of the input switching device 13 is monitored for a change indicating the beginning of a scan. Initialisation, scanning, selection and control programs which can be adapted for use in the present apparatus are described in GB 2137001B.

Each of the input station junction and switching units 14 has manually settable switches such as 24, 25 and 26 for setting a scan rate, input mode, and scanning delay. as in the apparatus of GB 2137001B or in the apparatus of GB 2058419. The states of these switches are sensed by the CPU in the initialisation program. The scan rate, input mode and scanning delay of each one of the input stations 11 and 12 are independently settable, so that the input stations can be adapted for use by different users respectively, e.g. two patients in a ward. The various manually operable switches must be set in the appropriate states by a helper.

The switching devices 22 coupled to the serial bus 21 control appliances such as electric fires, radio, television, door locks, curtains, bed adjusting mechanisms, and tape recorder, and any other electrically powered appliances whose functions can be controlled by relays or relays and control motors. Each device 22 has a UART which receives serial data from the CPU in the control unit.17 and 8 transmits serial data back to the CPU. The output of the UART to the device 22 is coupled to one or more control relays of the device. The input of the UART from the device 22 is coupled from manually settable encoding switches which identify the particular device and indicate what relay switches are controlled by the device 22. The current states of the controlled relays can be sensed from internal status registers of the UART and such data is read by the CPU as required. The identity code of the device 22 established by the manually settable switches is also used by the UART to ensure that the device responds only to commands intended for that device.

In the initialisation program, the CPU ensures that all devices which may be present are in a safe condition, which is the reset condition. In this particular example, a total of 126 devices can be controlled. Each device 22 has a seven bit identification code.

Each device 22 also has a manually operable push button switch 27 the state of which is also sensed by the control unit 17 through data transmitted by the serial link 21. Whenever the push button 27 is operated, the control unit 17 changes the state of the associated appliance, i.e. from ON to OFF, or from OFF to ON. The change of state is indicated on the screen of the active monitor 15.

An interrupt program is run every 20 milliseconds and consists in the transmission of one device address and the currently required command for that device, this transmission occupying 7 milliseconds and being effected at 2400 baud over the serial bus 21. The control unit 17 has a UART for this purpose which also receives any response from a device 22 which is present and has the currently transmitted address. The state of the device 22 is encoded at the device and transmitted back to the control unit 17 together with the identification code of that device. At the control unit 17, the CPU receives automatic confirmation of each transmission by its UART, feedback being provided. Identification and status data is only received by the CPU if the currently addressed device 22 is present.

Status data from a device 22 is preferably transmitted as a 16 bit parameter and compaction is used to ensure economical use of data bits, i.e. no bits are assigned to status conditions which are effectively constant. When no commands are being input by the user, the interrupt program runs on a preset sequence through the 9 addressing of the possible 126 devices 22. However, whenever a selection is made by the user that involves an operation at a device 22, the interrupt program sequence of addressing of the devices 22 is altered so that the sequence starts with the device which is to be controlled.

Fig. 4 is a circuit diagram of part of a switching device 22 and shows its UART 30 connected to the serial bus 21. in this example the control unit 17 and the switching device 22 communicate in half-duplex mode. Thd UART 30 is driven by a crystal-controlled clock 31. As a particular example, the UART 30 is an MC 14469 and the clock frequency is 307.2 kilohertz. The circuitry includes two banks 32,33 of eight manually settable single pole switches. One bank 32 has one side of all of its switches grounded and the other side connected to respective input pins of the UART 30, which in the example chosen are pins 4 to 11. The other bank 33 has one side of seven of its switches grounded, the other side of six of these seven connected to respective pins, input pins 12 to 17, of the UART 30, the other side of the seventh grounded switch 38 connected to one end of a resistor 34 coupled through a protective diode 35 to the positive supply line 36, and the eighth switch 39 connected in the source lead of a field effect transistor (FET) 37 used as a transponder switch by the UART 30. The drain lead of the FET 37 is connected directly to the serial bus 21, and its gate lead is connected to the serial output pin of the UART 30, which in the example is pin 21. The switch 39 must be closed for the transponder FET 37 to be operable. In the diagram of Fig. 4, pins 1 to 20 the UART example, MC 14469, are represented at the left hand side of block 30 as viewed, with pin 1 at the top and pin 20 at the bottom, and pins 21 to 40 are represented at the right hand side of block 30 as viewed, with pin 21 at the bottom and pin 40 at the top. Pins 21, 22, 23, 24, 25 and 27, and pins 18 and 20, are grounded. Pin 19 is the serial input pin of the UART and is coupled by a resistor 40 to the serial bus 21. A reset signal at power up is coupled to the reset pin, pin 3, from a 10p Farad capacitor 41 which is normally held charged to the level of an enabling signal for the UART by a parallel combination of a 10 megohm resistor 42 and a diode 43 in series with a 220 kilohm resistor 44.

- Seven parallel output pins, pins 33 to 39, of the UART 30 are connected to seven driver circuits in a bank of eight driver circuits provided, in this example, in the form of an integrated circuit 45, type ULN 2804A. The outputs of these seven driver circuits are connected respectively to seven relay control circuit terminals 46 to 52. The UART 30 can thus control up to seven relays. The relay control circuit connected to the terminal 46 is the control circuit of the relay used to control mains power supply to the appliance controlled by the switching device 22 incorporating the circuit of Fig. 4. If this appliance has other controlled functions, the relays controlling these functions are controlled by respective relay control circuits connected to one or more of the terminals 47 to 52. Fig. 5 shows the relay control circuit and relay circuit connected to the terminal 46. Two further terminals, 53 and 54, are part of the circuit of Fig. 5 and are connected to the fixed contacts of the push button switch 27. operation of the push button switch 27 completes a connection between the terminals 53 and 54, thereby grounding a node between two series resistors 55, 56 coupling the diode 35 to another parallel input pin, pin 27, of the UART 30. Hence the UART 30 is able to sense momentary closure of the push button switch 27.

As shown in Fig. 5, the terminal 46 is connected to the control electrode, in this example the gate, of controlled switch 57. The power electrodes, here the collector and emitter, of the switch 57 are connected t.o one end of the coils of a relay RL and to the ground terminal 54 respectively. Power for the relay RL and the switch 57 is provided by a rectifying unit 58 having an output smoothing capacitor 59 and receiving a low voltage a.c. mains frequency input from a step down transformer 60 having its primary connected between the live and neutral lines L and N of a domestic a.c. mains supply when a mains plug 61 of the circuit is inserted into an a.c. mains output socket (not shown) and the associated mains switch (not shown) turned on. The earth line E of the mains plug 61 is connected to the negative d.c. output terminal of the rectifier unit 58 and to the terminal 54.

A power output socket 62 provided to receive the mains power plug (not shown) of the controlled appliance (not shown) has an 0 earth contact 63 connected to the earth line E, and two other contacts 64 and 65 which are respectively connected to two fixed contacts 66 and 67 of the relay RL. A moving relay contact 68 associated with the fixed contact 66 is connected to the live line L of the plug 61, and a moving relay contact 69 associated with the fixed contact 67 is connected to the neutral line N of the plug 61.

The fixed and moving contacts 66 and 68 form one normally open pair of relay contacts, and the fixed and moving contacts 67 and 69 from another normally open pair of relay contacts. Whenever the coils of the relay RL are energised, the contact 64 of socket 62 is connected by the contacts 66 and 68 to the live pin of the plug 61, and the contact 65 of the socket 61 is connected by the contacts 67 and 69 to the neutral pin of the plug 61.

In use when the plug 61 is engaged in a socket (not shown) supplying mains power, and a controlled appliance has its plug (not shown) engaged in the socket 62, the supplying of power to the appliance is controlled by the state of the switch 57 as determined by the control signal applied to the terminal 46. The state of control. and hence that of the switch 57, can be changed by an able bodied attendant pressing the push button 27 momentarily.

If the push button 27 is pressed momentarily, the UART 30 changes the state of a status bit stored within the UART 30, so that the change indicates that actuation of the push button 27 has occurred. This status but is transmitted back to the control unit 17 at the next addressing of the UART 30 in the interrupt program described hereinbefore. Detection of "push button actuate&' by the control unit 17 results in an appliance status bit in the control unit memory (not shown) being toggled, i.e. being changed from 0 to 1 or from 1 to 0, for the appliance associated with the particular UART 30. The change of the appliance status bit results in a change in the status of the appliance as displayed on the screen 23 of the monitor 15 if active, or only in a corresponding screen memory (not shown), and a corresponding change in the state of the control signal applied to the control terminal 46. The interrupt program is also restarted from the interrogation of the switching device 22 with the actuated push button 27, and the resultant detection of "push button actuated" is ignored.

12 - The control unit 17 detects "push button actuateC by comparing the state of the received status bit associated with the push button 27 with a memory bit which is an image of the received status bit received at the previous run of the interrupt. If the memory bit and the currently received bit are in the same state, i.e. both 0 or both 1, the push button 27 has not been actuated in the last 20 milliseconds. If the states of these two bits differ, then the the push button has been actuated in the last 20 milliseconds.

The identity of the UART 30, i.e., which switching device 22 associated with which input station 14 and what relays are controlled by the UART 30 is set by the states of the switches of the banks 32 and 33 connected to pins 4 to 17 and 29 of the UART 30.

The resistor 34 coupling pin 29 to the positive supply line 36 through the diode 35 is necessary since the pin 29 has no internal pull up resistor.

Pins 30 and 32 of the UART 30 are connected together by a link to ensure that the UART 30 automatically transmits back to the control unit 17 immediately after receiving an instruction from the control unit 17. Pin 30 of the particular UART 30 in the present example is the output terminal for a pulse generated by the UART when data from the- control unit 17 is correctly received, and pin 32 is the input terminal for a pulse to trigger the sending of data back to the control unit 17.

13 -

Claims

CLAIMS f 1. A control system for controlling a plurality of electrically

operable switching devices, the system having a control unit coupled to the plurality of switching devices and to at least one input station, the or each input station having an input device actuable by a disabled user and a visible display means for displaying information relating to the system, the control unit being adapted to effect control of the said plurality or a predetermined group of the switching devices in response to actuation of the or any one Ik said input device, and at least one of the switching devices including manually operable means for signalling a request to the control unit to change a control state of the switching device, the control unit being adapted to sense the request and to so control the switching device as to effect the requested change.
2. A control system according to claim 1, wherein the or each visible display means comprises means for presenting a television type raster.
3. A control system according to claim 1 or 2, wherein the control unit is coupled to the switching devices by a serial link.
4. A control system according to any preceding claim, wherein the control unit is adapted to cause an effected requested change to be indicated by the display means of the input station or one of the input stations.
5. A control system according to any preceding claim, wherein the manually operable means is in the form of a push button switch.
6. A control system substantially as described hereinbefore with reference to Figs, 1, 4 and 5 of the accompanying drawings.

Publiblied 1988 at The Patent Office, state House, 68171 High Holborn, London WCIR 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con- 1/87.