GB2195475A

GB2195475A - Electronic programmable logic and timing device

Info

Publication number: GB2195475A
Application number: GB08720247A
Authority: GB
Inventors: Roderick John Collins; Desmond Francis Mullin
Original assignee: IMI Pactrol Ltd
Current assignee: Pactrol Controls Ltd
Priority date: 1986-08-29
Filing date: 1987-08-27
Publication date: 1988-04-07
Anticipated expiration: 2007-08-27
Also published as: GB8620947D0; GB2195475B; GB8720247D0

Abstract

A programmable logic and timing device for a central heating boiler or an immersion heater is described. The programming module 12 is separable from the timer/control module 10 after it has been set, eg in the factory, to provide an inexpensive tamper-proof time controller capable of remaining on time for the life of the product. The controller could be reset if necessary by a service engineer by plugging in a programming module. <IMAGE>

Description

SPECIFICATION Electronic programmable logic and timing device The present invention relates to electronic programmable logic and timing devices.

At present, many large scale integrated cir-cuits having a dedicated function are being produced from microcomputer based circuits and uncommitted logic arrays.

The end product is typically an electronic assembly capable of controlling one or more output lines on a time or logic basis, often triggered by a change in state of one or more input lines.

The end-user of such a product is given a limited programming facility to enable local logic and/or timing functions to be carried out. To enable programming to be achieved by the end-user, one or more programming push buttons or switches may be provided together with some form of display to enable the user's added program to be verified. The local programming feature thereby adds significant costs to the overall controller cost.

In addition, some end users, particularly in the domestic situation, find such programming difficult and this can lead to either a reluctance to buy the product or an inability to use all its features correctly.

One common example of a programmable controller used in a domestic situation is the central heating/hot water time controller, where the operation of a central heating boiler and water pump can be automatically controlled by programmable time switches.

Another product is a programmable time switch to control the operation of a domestic electric immersion heater, the timer being set to energise the heater when the electrical supply tariff is at its lowest.

Recently there has been a move away from electro-mechanical timers and into electronicbased units. As described above all current units suffer from the problem of being difficult to programme while costing typically 50% more than their electro-mechanical equivalents.

It is an object of the present invention to provide an electronic programmable logic and timing device which is relatively cheap to produce and whose operation is simplified from the viewpoint of the user.

The present invention, in accordance with its broadest aspect, resides in a programmable logic and timing device for controlling the on and off times of a product, the device comprising selectably interconnectable modules containing respectively a timer/control circuit and a programming means, arranged such that when a desired programme has been set by means of the programming means, the programming module can be detached from the timer/control module leaving only the latter module permanently coupled to the product being controlled.

The present invention, in accordance with a second aspect thereof, resides in a programmable logic and timing device for controlling the on and off times of a product, the device comprising an integrated circuit which performs timekeeping and programme storage functions and which is selected to demand a very low supply power, typically less than 10,uA at 1.5 volts d.c., the integrated circuit being disposed in a timer/controller module and being coupled permanently to a battery power source in the latter module capable of operating the timer circuit for a period at least long enough to complete the factory testing, storage, despatch, sales and installation stages but preferably for the operational life of the product, programme information such as time of day, on times and off times being enterable at the manufacturing and installation stages by means of programming means disposed on a programming module which is selectably connectable to the timer/controller module when programme changes are to be made.

It should be noted that the term "programming means" is intended to cover any suitable means of entering the relevant programme and will include touch sensitive buttons, keyboard buttons, and indeed any means by which programme information may be entered. Thus, the programme could be set, without manual intervention, by means of automatic equipment which could be coupled to the memory circuits of the timer/controller module at the production stage, the required data being entered directly in the form of binary signal levels.

However, provision would still preferably be made for the possiblity of altering the programme after installation by means of a selectably connectable programming module equipped with push-buttons or the like, to enable manual entry of program information.

The programming module can also include a display device to enable, inter alia, program details to be checked.

The invention is described further hereinafter, by way of example, with reference to the accompanying drawing, which shows diagrammatically one embodiment of a programmable logic and timing device in accordance with tha invention.

The device is formed in two separable parts, namely a main timer/controller module 10 and a programming module 12 which is capable of being selectably plugged into or onto the module 10 when programming alterations are to be made.

The main module 10 is adapted to be permanently mounted in its operational site, for example adjacent a domestic central heating boiler, and contains an electronic timer/logic circuit 14, an output interface 18 and a power supply 18. The power supply 18 is coupled to the mains and supplies low voltage d.d, to the circuits 14 and 16 and also, if necessary, to the programming module 12. A long life battery 20, which can be a primary source or be re-chargeable, is provided in the module 10 to maintain operation of the timer/logic circuit 14 in the event of mains failure and/or prior to mains connection. The output interface provides output signals for transmission to the relevant systems or product being controlled, for example for controlling the on/off times of a domestic central heating boiler.

The programming module 12 contains a display 22 and a plurality of push-buttons 24.

The arrangement is such that when the modules 12 and 10 are interconnected, the timing and control functions the circuit 14 can be adjusted and programmed by use of the buttons 24. The display 22 can indicate the programmed conditions. When the module 12 is removed, the program cannot be altered.

Thus, the programming function can be removed from the user who therefore sees only a "black box" which needs no adjustment in the normal course of events. The program information, such as the time of day, on times and off times, may be entered at the manufacturing or installation stages after which the module 12 containing the program buttons and display is removed, leaving the customer with a tamperproof time controller capable of remaining on time for the normal operational life of the product while obviating the need for costly programming components.

If timings are required to be changed within the life of the product, a programming module 12 is simply plugged into the unit 10, the timings changed and then the module 12 then removed again.

The battery power source is preferably capable of operating the timer circuit for a period at least long enough to complete the factory testing, storage, despatch, sales and installation stages. If rechargeable, the battery must therefore provide a minimum discharge life of 1 year while a primary battery should provide a life in excess of 5 years. In the system illustrated, with a timer consumption of 10,uA/hr from a 1 Ampere-hour battery, the theoretical battery life can be expected to be in excess of 10 years.

Preferably, the interconnection between the modules 10 and 12 is a simple plug and socket connection to enable ease of connection and disconnection but any convenient form of interconnection can be used.

Claims

1. A programmable logic and timing device for controlling the on and off times of a product, the device comprising selectably interconnectable modules containing respectively a timer/control circuit and a programming means, arranged such that when a desired programme has been set by means of the programming means, the programming module can be detached from the timer/control module leaving only the latter module permanently coupled to the product being controlled.

2. A programmable logic and timing device for controlling the on and off times of a product, the device comprising an integrated circuit which performs timekeeping and programme storage functions and which is selected to demand a very low supply power, typically less than 10,uA at 1.5 volts d.c., the integrated circuit being disposed in a timer/controller module and being coupled permanently to a battery power source in the latter module capable of operating the timer circuit for a period at least long enough to complete the factory testing, storage, despatch, sales and installation stages but preferably for the operational life of the product, programme information such as time of day, on times and off times being enterable at the manufacturing and installation stages by means of programming means disposed on a programming module which is selectably connectable to the timer/controller module when programme changes are to be made.

3. A programmable logic and timing device as claimed in Claim 1 or Claim 2 in which the programme is set, without manual intervention, by means of automatic equipment which is coupled to the memory circuits of the timer/controller module at the production stage, the required data being entered directly in the form of binary signal levels.

4. A programmable logic and timing device as claimed in any of the Claims 1 to 3 in which means are provided for altering the programme after installation by means of a selectably connectable programming module.

5. A programmable logic and timing device as claimed in any preceding claim inciuding a display device to enable, inter alia, program details to be checked.

6. A programmable logic and timing device as hereinbefore described with reference and as shown in the accompanying drawing.