GB2109966A - Control systems - Google Patents

Abstract

A system wherein operations at a plurality of transaction terminals, which may be point-of-sale, booking or accounting terminals, are controlled from a central location. At the central location there is a main processor unit and data storage means. At each transaction terminal there is a subsidiary processor unit, peripheral devices, for example a printer, display unit or bar code reader, and peripheral processor units. Each peripheral processor unit controls operation of an associated peripheral device in accordance with signals applied thereto by an operator or sensing device or from the main processor unit, via the subsidiary processor unit. Each subsidiary processor unit checks, decodes and converts to a suitable format signals transmitted between the associated peripheral devices and the main processor unit. The main processor unit controls access by peripheral devices to information stored at the central location and processes information prior to transmission from the central location to a subsidiary processor unit. <IMAGE>

Description

SPECIFICATION Improvements in control systems This invention relates to systems wherein operations at a plurality of transaction terminals are controlled from a central location.

In supermarkets, departmental and variety stores there are locations at which sales are transacted through a till or point of sales terminal. It is desirable for operation of each till or point of sales terminal to be controlled from a central location. At the central location there is a store of data relating to the type, cost and availability of all goods sold at each till or point of sales terminal. A record of transactions effected at each till or point of sales terminal is also maintained. Information relating to the goods is then readily available to management at the central location.

A central location for controlling transactions at a plurality of remote transaction terminals is also desirable when the transaction terminal is a booking or accounting terminal rather than a till or point of sales terminal.

If such a system is controlled by a single microprocessor device in a main controller at the central location, the microprocessor must be responsible for all "task management", "resource management" and "input/output management".

By "task management" is meant the initiation and control of a series of tasks which may be carried out simultaneously or sequentially by the processor. In general, one task can be initiated whilst the previous task is still being executed, since the speed of operation of the microprocessor is faster than that of an input or output device, such as a keyboard, disc unit or printer. "Resource management" means controlling access by the various tills or point of sales terminals to shared disc drives, printers and displays at the controller. Similarly, "input/output management" involves controlling access by the individual tills or point of sales terminals to files and records held in storage at the controller.

Unfortunately, such a multi-task system becomes so complex that it consumes most of the power of the processor, with the result that little time is available to handle the tasks themselves and there is a limittothe number of tasks that can be handled.

According to the present invention there is provided a system wherein operations at a plurality of transaction terminals are controlled from a central location, the system comprising a main controller which is located at the central location and comprises a main processor unit and means for storing data relating to transaction terminals remote from the main controller and each having a subsidiary processor unit, at least one peripheral device which generates an input signal representing a transaction when actuated by an operator or by an associated sensing device or which receives command signals from the main controller and displays information represented thereby, and at least one peripheral processor unit associated with the peripheral device or devices, the or each peripheral processor unit being adapted to control the operation of the associated peripheral device or devices in accordance with command signals applied thereto from the main processor unit via the subsidiary processor unit or input signals resulting from the actuation by the operator or sensing device, the subsidiary processor unit being adapted to check, decode and convert to a suitable format signal transmitted between the associated peripheral device or devices and the main processor unit, and the main processor unit being adapted to control access by peripheral devices to information stored in the controller and to process information prior to transmission to a subsidiary processor unit.

Each of the transaction terminals may be a till or point of sale terminal. Alternatively, at least one of the transaction terminals may be a booking or accounting terminal.

Suitably, the main controller further includes at least one communications processor for controlling transmission of signals via a communications line between the main processor unit and a subsidiary processor unit or a remote computer.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which :- Figure 1 is a block schematic drawing of a till or point of sales terminal in a system according to the invention; Figure 2 is a block schematic drawing of a main controller in the system including the till or point of sales terminal shown in Figure 1.

The system shown in the drawings is designated for use in branches of multiple chain stores, departmental or variety stores or supermarkets. Each of the transaction terminals of Figure 1 is a till or point of sales terminal which is located at the appropriate department or check-out point in the store whilst the main controller of Figure 2 is housed at a central location, where it is readily accessible to the store management.

Referring to Figure 1, each till or point of sales terminal in the system includes a subsidiary or till microprocessor unit 5, a plurality of peripheral devices, and a plurality of peripheral processor units associated with the peripheral devices.

A first of the peripheral devices is a contact-less keyboard 1 containing up to 105 keys. Electrical outputs from the keyboard 1 are connected via an associated printer control processor unit 3 to the subsidiary processor unit 5.

A second peripheral device is a receipt printer 6, which provides a printed record of transactions effected at the till or point of sales terminal and is also coupled to the control unit 3. The printer 6 can be a 40 column or 18 column split platen printer and/or a flatbed printer.

Two further peripheral devices are independent display units 7, one for viewing by a customer and one for viewing by an operator. Each unit 7 provides a line display of alpha-numeric characters, being capable of displaying up to 20 or 40 characters.

Alternatively, a CRTfor displaying multiple lines of alpha-numeric data may be provided. The units 7 are connected to an associated display processor unit 9, which controls their operation, as hereinafter de scribed.

Each till or point of sales terminal in the system may be required to operate with input signals representing the type and quality of goods being sold, these signals being derived from a peripheral device in the form of a bar code reader (not shown).

The bar code reader may be adapted to distinguish between and to decipher one or more different codes. A wand processor unit 11 is provided for processing signals from such a reader. The unit 11 may also be adapted to drive a credit card reader.

The display processor unit 9 and the wand processor unit 11 are connected via a main bus 13 to the subsidiary processor unit 5. Also connected to the bus 13 is a communication processor unit 15, which is connected via coaxial cables 17 to the main controller of Figure 2 and manages the transmission of signals between the till and the main controller.

Referring now to Figure 2 of the drawings, the main controller of the present system includes a main processor unit 18 which is an overall charge of the operations performed in the whole system, as hereinafter described. The processor unit 18, like the subsidiary processor unit 5 and the processor units 9, 11 and 15 of Figure 1, is a Zilog Z-80 CPU.

Associated with the main processor unit 18 are data storage means 19, formed of a series of 16K RAM's. The storage means 19 are connected to the unit 18 via a main bus 21. Further storage means is provided by a separate mass storage unit 23, which may contain floppy or Winchester discs, a bubble memory or further random access memories. Suitably, the storage 23 contains two floppy discs, one or two sides and provides 240K to 1 M Byte of storage.

The mass storage 23 is connected to the main processor unit 18 via the bus 21 and a peripheral processor unit in the form of a disc processor unit 25.

A communications processor unit 27 is provided for managing the transmission of signals between the bus 21 at the output of the main processor unit 18 and the coaxial cables 17 which connect the main controller to the tills. The unit 27 also handles transmissions along an external communications line to a remote computer. More than one communications processor unit 27 is provided if the number of tills is greater than the number which is conveniently connected via a single coaxial cable loop.

As shown in Figure 2, the main controller also includes as a further peripheral device a 40 column printer 29 for displaying information required by management. The printer 29 is coupled to the main processor unit 18 via a printer control processor unit 31, which is a further peripheral processor unit.

It will be clear from the number of processor units provided in the present system that the processing power is widely distributed. This contrasts with the usual system, referred to above, in which the processing power is concentrated in a single microprocessor at the central location.

In the present system, a master program for controlling operation of the transaction terminals resides in the main processor unit 18 at the main controller. In this unit 18 and the associated storage means 19 and disc storage 23 is data representing the type and quality of each item of goods sold at each till or point of sales terminal, the price of each item, the quantity of that item remaining in the store, etc. The main processor unit 18 therefore performs the application logic and manages the total system.

In particular it handles the following major functions.

First, "task management" i.e. creation, deletion, scheduling of tasks required by terminals or by management via an external communications line so as to share the unit 18's time, and advising recovery when a task encounters an abnormal error condition.

Secondly, "resource management" i.e. limiting or denying access by the tills to resources such as communications, memory banks, disc drives, display units etc. in accordance with a predetermined hierarchy via a scheme of locks.

Thirdly, "input/output management" i.e. managing buffer pools, memory banks and queues of input/output requests and synchronising the various tasks with their input/output requests.

Finally, the main processor unit 18 applies operating system messages to the printer 29 via the printer control unit 31.

It will be appreciated that the word "management" is used to emphasise that the main processor unit 18 does not actually perform the abovementioned functions but merely delegates the functions to other processor units. Included in these other units are the disc processor unit 25 and the communications processor unit 27 of the main controller.

The disc processor unit 25 performs those tasks associated with the mass storage 23. These are (1) disc drive tasks such as turning on and off the drive, detecting diskette insertion and rejection, and detecting and recovering drive error, (2) diskette management tasks such as error detection, recovery and back-up, global data statistics, and density selection and (3) file management tasks such as the creation, deletion and maintenance of the file directory and indexes, the creation, deletion, insertion and maintenance of data records, and provision of security.

The communications processor unit 27 handles external communications via a modem and via external communications media (such as British Telecom) to and from a remote host computer.

Within the system the unit 27 handles communications via the cables 17 with up to eight tills or other transaction terminals including a suitable transaction interpreter. The following functions are covered - (1) detecting the presence or absence of a till, (2) managing the communications link between the main controller and the tills, (3) detecting and correcting errors in the communications loop from the main controller to the tills and (4) 'polling' of the tills.

As mentioned above, a second communications processor unit may be provided. If present, this second unit performs the same functions as the unit 27 except that instead of being connected to a modem it is used to control other remote devices such as a V.D.U., line printer, etc. through an RS 232 interface.

In each of the tills of the present system the subsidiary microprocessor unit 5 manages the func tions of the till and interprets command signals from the main controller. Within each unit 5 is a till interpreter, which is a piece of software forming a part of the overall operating system. The till interpreter receives data from processor units associated with peripheral devices in the till, converts the data to a suitable format, and then causes the communications processor unit 15 to send an appropriate message or data to the master controller.Likewise, each till interpreter receives command signals trans- mitted from the master controller via the communications processor unit 15, decodes the command signals and then applies appropriate signals to one of the other processor units within the till, causing an event to happen at the peripheral device controlled by that processor. Finally, there is within the till interpreter a "stand alone" routine which is employed when a breakdown in communications with the main controller is detected. This enables the till to continue to perform basic functions essential to trading, such as issuing receipts, maintaining securitytotals, opening and closing the cash drawer, recording and displaying amounts of cash taken, etc.

Each peripheral microprocessor unit within a till controls the function of the specific peripheral device or devices associated with that unit.

Thus, the printer control processor unit 3 has a program for controlling the actions of the keyboard 1 and the printer 5. The display processor unit 9 controls the two displays 7 so that each can operate independently of the other, i.e. different messages can be displayed almost simultaneously. The displays are "soft", i.e. a variety of different characters can be generated to suit a particular application, this being achieved by programming the unit 9 to interpret command signals from the interpreter in the unit 5 in whatever way is required. The communications processor unit 15 serves to manage the communications link between the till and the main controller. There is also a spare R S232 interface which can be used to attach a V.D.U. or line printer to the till, or even another independent communications link.Finally, the wand processor unit 11 enables a light pen reader to be connected to the till.

The unit is programmed to identify and to decode input signals representing a variety of forms of bar-coding or it is programmed to recognise OCR-A printing through a light pen reader.

As indicated above, the function of the till interpreter in the subsidiary processor unit 5 is to provide a method of communicating messages between the main controller and the till, these messages being requests for processing by the till or commands from the main controller to the till. The form of command signals handled by the interpreter is described below, though these can be increased or amended to suit a user. The main body of the interpreter is concerned with the input, displaying and printing of data. Within these kinds of operation, data can be divided into categories of alpha-numeric text, integer and cash. The text data type is merely storing input - output handling, whereas integer and cash data are always five byte binary coded decimal fields and so undergo a certain amount of editing.

Other facilities provided are access to the internal totals of the till, control of the till drawer and beeper, and error message handling.

Communication from the main controller and the interpreter in the subsidiary processor unit 5 is by means of the communications processor unit 15.

Instructions to the unit 5 are issued by use of a command string, which is set up by the application program in the main processor unit 18 of the main contrioller. The subsidiary processor unit 15 is then called with a pointer to this string and also an indication of whether data isto be returned by the till. If there is incoming data this will be pointed at by the unit 15. The format of the command string varies depending on the type of operation and will be described fully later. The most complex of the operations is the input function which apart from providing some validation for numeric fields also allows a number of alternative keys for terminating input. These keys, if required, must obviously be sent as part of the command string.A prompt and input function is not provided and therefore the display command must be used if a prompt before input is required.

As stated previously integer and cash fields are transferred as fixed length BCD digits. However, cash fields are only actually 9 characters, the last nibble of the five byte field being the half-pence flag.

This will always be a zero or a five, indicating the presence of a half-pence in the field. The whole field can therefore be treated as being tenths of pence.

Display and print commands require additional information to determine which type of display or printer device is being used. This information is given in a 1 byte field following the command type. It takes the form of a bit pattern where each bit represents output on one particular device. This allows for output on more than one device for any one command string i.e. a message could be sent to the operator and customer displays at the same time. The lists of bit patterns are given with the command formats.

Input commands from the keyboard 1 or other input devices at the till have a command string wherein the first character denotes the command type, the second character denotes the maximum number of characters allowed, the third the possible inclusion of a list of alternative terminating characters and the fourth character is a terminating ETX character. The format for the input statement is therefore (a) command type - a 1 byte field representing an alpha numeric input, an integer input, a cash input or an alpha numeric or wand input, (b) maximum entry - a 1 byte field indicating the maximum number of digits allowed (a maximum of 10 for integers and 9 for cash), (c) additional terminators - a 1 byte entry for each key which is allowed to terminate an entry other than the 'enter' key, or a range of keys introduced by a 4 and followed by two bytes specifying the range limits, and (d) a string terminator.

The facility to specify additional terminators is provided so that for example cash fields may be entered and terminated by a method of payment key.

In addition to the list of commands given, there ere also two single character input commands. For these only the command type is sent, either 14 (HEX) for input character or 15 (HEX) for check keyboard.

Other command signals generated within the system, such as display and print commands from the main controller to the tills, data transfer commands from the tills or the controller, and certain additional commands required for the till cash drawer and beeper, have structures similar to those described above for the input commands.

The manner in which a typical transaction, a cash sale, is dealt with by the system, will now be described.

Assuming the system is operative, an operator initiates the transaction by depressing the appropriate keys on the keyboard 1. First, numeric keys (e.g.

565) which represents particular goods are depressed. Secondly, a PLU key is depressed, indicating that details of the price of these goods are required.

The printer control processor unit 3 receives signals from the keyboard 1 and identifies the keys depressed. An input signal representing the signals from the keyboard is applied from the unit 3 to the subsidiary processor unit 5.

At the unit 5 the input signal from unit 3 is identified and the appropriate command string (as described above) is generated. In this string, the command type field represents an integer input and the terminator is one representing the fact that a PLU key was depressed.

The command signal from the subsidiary unit 5 is applied via the bus 13 to the communications processor unit 15, where the signal is held ready for transmission to the main controller. At the same time, a command signal is applied from the unit 15 to the display processor unit 9, where the signal is decoded and results in a display of "PLU 565" on the associated displays 7.

If the operator depresses too many digits, the processor unit 3 causes a tone generator to generate a beep.

The communications processor unit 27 sequential- ly scans the inputs from all of the tills connected to the main controller, in accordance with the programme stored in the unit. Accordingly, the flag at the output of the unit 15 is detected and the command signal stored at that unit is called in to the main processor unit 27. The unit 27 then interrupts the main processor unit 18 to signify the presence of a request at the input to the controller. The unit 18 accepts the input in accordance with a priority sequence laid down in its programme.

A signal is now applied from the unit 18 to the disc processor unit 25, requesting information concerning the goods identified by the above-mentioned code 565. Whilst the unit 18 now proceeds with other parts of its programme, the unit 25 checks whether the information requested is stored in one of the RAM's 19 or on one of the discs 23. Assuming the information is in one or other of these locations, the unit 25 flags the record of the information to prevent access thereto by other sources and then extracts the information.

During the course of its programme the master processor unit 18 calls up the information extracted from a RAM 19 or disc 23. The unit 18 then converts the information into a format suitable for interpretation by the subsidiary processor unit 5 at the till. The information is then transmitted to the till as a command signal, under management by the unit 27 at the main controller and the unit 11 at the till.

At the till, the subsidiary processor unit 5 interprets the command signal and activates the display processor unit 9. The latter actuates the display units 7 so that a description and price of the goods appears on the customers display and these two pieces of information together with a request for details of the next item appear on the operator's display.

Assuming there is to be a cash payment, the operator now depresses the cash key on the till. This is recognised by the print control processor unit 3, which actuates the subsidiary processor unit 5 so that the display processor unit 9 causes a display "Amount" to appear on the operator's display 7.

The operator now keys in the amount tendered by the customer. The appropriate command signal is then applied from the print control processor unit 3 to the subsidiary processor unit 5, which transmits the information, together with a request for details of the change required, via the communications processor unit 15 to the main controller.

Upon receiving the request, the main processor unit 18 at the controller calculates the amount of change and generates a command signal which is transmitted to the subsidiary processor unit 5 at the till. In response to this command signal the unit 5 issues a command to the display processor unit 9, which causes the change to be displayed on the operator and customer displays 7 for a predetermined time, the till drawer to be opened, and a receipt to be printed.

Claims (10)

1. A system wherein operations at a plurality of transction terminals are controlled from a central location, the system comprising a main contrller which is located at the central location and comprises a main processor unit and means for storing data relating to transactions effected at each of the transaction terminals, and a plurality of transaction terminals remote from the main controller and each having a subsidiary processor unit, at least one peripheral device which generates an input signal representing a transaction when actuated by an operator or by an associated sensing device or which receives command signals from the main controller and displays information represented thereby, and at least one peripheral processor unit associated with the peripheral device or devices, the or each peripheral processor unit being adapted to control the operation of the associated peripheral device or devices in accordance with command signals applied thereto from the main processor unit via the subsidiary processor unit or input signals resulting from the actuation by the operator or sensing device, the subsidiary processor unit being adapted to check, decode and convert to a suitable format signals transmitted between the associated peripheral device or devices and the main processor unit, and the main processor unit being adapted to control access by peripheral devices to information stored in the controller and to process information prior to transmission to a subsidiary processor unit.

2. A system as claimed in claim 1, wherein the main controller includes at least one further peripheral device for displaying information represented by signals from the main processor unit, and at least one further peripheral processor unit adapted to control operation of the or each further peripheral device in accordance with command signals from the main processor unit.

3. A system as claimed in claim 1 or 2, wherein the main controller includes at least one communications processor unit for controlling transmission of signals via a communication line extending between the main processor unit and a subsidiary processor unit or a remote computer.

4. A system as claimed in claim 1,2 or 3, wherein the data storage means in the main controller comprises a random access memory, and the main controller further comprises a further peripheral device comprising a separate mass storage unit.

5. A system as claimed in any one of the preceding claims, wherein each transaction terminal is a till or point of sale terminal comprising a keyboard for use by an operator in generating signals representing information concerning a transaction, a printer for providing a printed record of transactions effected at the terminal, and a peripheral processor unit associated with the printer and keyboard.

6. A system as claimed in any one of the preceding claims, wherein each transaction terminal includes a bar code reader or a credit card reader, and a wand processor unit associated with the reader.

7. A system as claimed in any one of claims 1 to 4, wherein each transaction terminal is a booking or accounting terminal.

8. A system as claimed in any one of the preceding claims, wherein each transaction terminal includes a peripheral device in the form of a display unit which displays information as a line of alpha numeric characters.

9. A system as claimed in any one of claims 1 to 7, wherein each transaction terminal includes a peripheral device in the form of a display unit which displays information as multiple lines of alpha numeric characters.

10. A system wherein operations at a plurality of transaction terminals are controlled from a central location, the system being constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.