WO1991008539A1

WO1991008539A1 - An electronic price information system

Info

Publication number: WO1991008539A1
Application number: PCT/SE1990/000790
Authority: WO
Inventors: Roland BRÄNNSTRÖM
Original assignee: Braennstroem Roland
Priority date: 1989-12-01
Filing date: 1990-11-29
Publication date: 1991-06-13
Also published as: SE8904072D0; SE466773B; SE8904072L

Abstract

The present invention relates to a price information system which includes a plurality of price information units (18) for displaying changeable information in, for instance, a shop or store. The system includes a main computer unit (10) which is connected to a communication unit (12). The information supplied to the computer unit (10) is transmitted to the communication unit (12). The communication unit transmits this information inductively, i.e. wire-less, to the various price information units (18), via a loop pair (14). The information is transmitted in the form of a sequence of messages, wherein the position of a message in the sequence denotes the price information unit (18) for which the message is intended according to a predetermined order sequence. When a price information unit (18) has received its specific message, the unit transmits a response signal to the communication unit (12). If the range of the communication unit (12) is too small for the shop in question, a number of slave units (16) with connected loop pairs (14) can be connected to the communication unit (12).

Description

An Electronic Price Information System

The present invention relates to an electronic price information system comprising a plurality of price information units for displaying changeable information in shops and stores, for instance.

Electronic price information systems for displaying prices, article numbers or like changeable information on the edge surfaces of shelves or the like in shops, stores or storage facilities are known to the art.

SE-441 477 describes a computer controlled electronic price information system comprising a plurality of displays arranged on shelves for the purpose of presen¬ ting the desired information, for instance the price of an article, the article number or like information. The information presented on the display unit is changed by the transmission of change information from a control unit to a display unit receiver, this transmission being effected over a wire-less connection, which may be a radio connection or an IR-connection. In this system, communication is effected solely from the control unit to the receiver, i.e. monodirectional communication.

EP-0 200 473 teaches a computer controlled electronic price information system which includes a plurality of display units for presenting changeable information, and a main control unit. Two-directional communication between the main computer unit and the display unit is achieved with fixedly mounted conductors between shelves and computer unit. When a display unit is mounted on a storage shelf, the unit is connected to the fixedly mounted conductors. The various display units are distinguished one from the other, by allotting to each display unit a code which is unique to a particular unit.

US-4,500,880 teaches a computer controlled electronic price information system which includes a plurality of display units which are arranged in groups, via fixedly mounted conductors, and each of which is connected to a respective local computer, these local computers being connected to a central computer. Two-directional or duodirectional communication between the display units and the central computer is effected through the fixed¬ ly mounted conductors. A specific display unit is addressed with the EAN-code belonging to that item of goods whose price is to be displayed on the display unit.

One disadvantage with the aforesaid systems in which duodirectional communication can be effected is that they utilize fixedly mounted conductors on the shelves of a store, shop or storage room. This renders the work involved in restructuring stores or storage rooms highly expensive and labourious. Furthermore, these known systems require the use of a code which is unique for each display unit, so that price information in¬ tended for a given article or goods is received and reproduced by the correct display unit. The use of these identification codes renders the total amount of information transmitted very voluminous, since each message that is sent in either direction must be accom¬ panied by said identification code. In many instances, no change is made in the information presented by the display units, and solely a functional control is carried out. In these instances, the largest part of the total quantity of information transmitted consists of the aforesaid identification codes.

The inventive price information system eliminates these drawbacks by having been constructed in accordance with the characterizing of Claim 1. The duodirectional communication between price information units, which display changeable information, and the communication unit connected to a main computer unit is effected via wire-less inductive coupling. This enables reconstruc¬ tion of a store, shop or storage room with respect, for instance, to the positions of the shelves therein to be carried out without needing to change the whole of the price information system.

The frequency intervals for the transmission of infor¬ mation via inductively coupled loops are limited. In the future, when the installation of electronic price information systems becomes common, a small bandwidth is to be preferred, since this will enable several systems to operate simultaneously. This is achieved in accordance with the inventive price information system in that no identification code for each price informa¬ tion unit is needed. This is achieved by transmitting the information in the form of a signal sequence with the messages, where the order of the message in said sequence determines the price information unit for which the message is intended. This applies to the exchange of information in both directions. The amount of information is thus reduced, which requires smaller bandwidths and reduces communication time. It also results in low current consumption in the price infor¬ mation units, since this consumption is contingent on the bandwidth of the information transmitted and the time required to effect the transmission. The fact that communication is effected in accordance with an ordered sequence which is predetermined with respect to the store or shop concerned, as mentioned in the aforegoing, increases security against unauthorized updating.

Good communication quality is necessary in order to maintain and ensure positive price information. This makes it necessary to check the quality of the com- munication sent to each price information unit. A large amount of information is required in order to establish communication quality in a statistically positive manner. This is achieved with the inventive price information system, in that each of the price informa- tion units receives the whole of the communication sequence in parallel and checks said sequence.

The invention will now be described in more detail with reference to an exemplifying embodiment thereof and with reference to the accompanying drawings, in which

Figure 1 is a simplified block schematic illustrating a price information system constructed in accordance with the invention; and

Figure 2 is a simplified block schematic of a price information unit used in the inventive price informa¬ tion system.

The inventive price information system illustrated in Figure 1 is intended for use, for instance, in shops, stores or storage rooms and includes a main or central computer unit 10, which may have the form of a personal computer or the like. The main computer unit 10 is connected to a communication unit 12, which is always connected to an inductively couple loop pair 14 in¬ stalled in the store, shop or storage room.

By loop pair is meant two loops (a loop is an electric conductor having mutually the same starting and finish¬ ing point) , which are placed in a manner such that when current is supplied thereto, the direction of the magnetic field is changed to the greatest extent pos¬ sible when the use of one loop is switched to the other. Arranged in the shop or storage room is a number of price information units 18 which, for instance, are placed on the shelves carrying the goods or items to which the information concerns. Each of the price information units 18 includes a display unit 28 (see Figure 2) which functions to display, for instance, price information and/or other information. Communica¬ tion between the unit 12 and the price information units 18 is effected in a wire-less fashion, by induc¬ tive coupling. When transmitting information to the price information unit 18, the communication unit 12 drives a sinus current in a loop pair 14. A magnetic field proportional to the current will then be genera¬ ted in space (Biot-Savarts law) . By changing the fre¬ quency of the sinus form, two states, so-called fre- quency modulation, are obtained, therewith enabling binary code information to be transmitted. The state "0" may be corresponded, e.g. by the frequency 48.96- 0.64 kHz, whereas the state "1" may, for instance, be corresponded by the frequency 40.96+0.64 kHz. Each price information unit 18 includes a loop on which there occurs a voltage which is proportional to the magnetic field derivative (Faradays Induction law). Furthermore, each price information unit includes two sampling filters which respond to the aforesaid fre- quencies. The information corresponded by the two states is reproduced in this way.

When the shop, store or storage room is so large that the range of the communication unit 12 is insufficient, it is possible to connect one or more slave units 16 to the communication unit 12. Each slave unit 16 is equipped with two loop pairs. When transmitting infor¬ mation, all slave units 16 and the communication unit 12 transmit in parallel, i.e. currents of mutually the same magnitude and the same rotational direction are generated in all connected loop pairs 14 simultan¬ eously.

Figure 2 is a simplified schematic illustration of an embodiment of a price information unit used in the price information system illustrated in Figure 1. Each price information unit includes a transmitting and receiving means 20, which in the illustrated embodiment consists of a loop. Connected to the transmitting and receiving means 20 is a detecting means 22 which func¬ tions to detect whether or not the message received is intended for this particular price information unit. The detection means 22 also functions to detect errors in the messages received. When the detecting means 22 of a specific price information unit detects that the message received is intended for this specific price information unit, the message is stored, if so requi¬ red, in a memory means 24 connected to the detecting means 22. At the same time, a response signal is sent to generating means 30 connected to the detecting means 22. The message stored in the memory means, e.g. in the form of price information, is decoded in a decoder 26 connected to the memory means 24, whereafter the deco- ded message is reproduced on a display unit 28 con- nected to the decoder 26. The system also includes a supply circuit 32, e.g. in the form of a battery, which is connected to the transmitting and receiving means 20 and to the display unit 28. The detecting means 22 is also able to detect general messages intended for all price information units, such as messages for switch- ing-off and switching-on the display unit 28. Although not shown in Figure 2, each price information unit includes means intended for detecting the communication start sequence, for monitoring the condition of the battery, and for visually displaying the battery sta¬ tus.

If, for instance, it is desired to change the price information shown on the price information units 18, the required information is fed into the communication unit 12, through a keyboard or some other means belong¬ ing to the main computer unit 10. The communication unit 12 converts this information to messages according to a prescribed order or sequence, which are then transmitted to the price information units 18 through the inductively coupled loop pair 14. The communication unit 12 transmits these messages in a sequence such that all price information units 18 receive mutually the same messages in parallel. Each price information unit 18 separates the message concerning, e.g. , price information for its particular price information unit 18, by virtue of the fact that the messages are trans¬ mitted in a predetermined call order, wherein the first message in a sequence is intended for a given, pre¬ determined price information unit 18, the second mes¬ sage in said sequence is intended for another predeter¬ mined price information unit 18, and so on. Because communication is effected in this manner, no identifi- cation codes are needed to distinguish between the various price information units 18. When the detecting unit 22 (see Figure 2) has detected the message in¬ tended for a specific price information unit 18, a response signal is produced and sent to the com unica- tion unit 12, via the transmitting and receiving means 20 (in the form of a loop). This may be effected through the slave unit 16, when the shop, store or storage room is so large that the range of the com¬ munication unit 12 is insufficient. The communication unit 12 identifies the price information unit 18 from which a given response signal is sent through the mutual call order of the response signals and the time slots between consecutive response signals. If no error is detected, the price information unit 18 for which the first message in the sequence was intended trans¬ mits the first response signal, whereas the second price information unit 18 will transmit the next res¬ ponse signal, and so on. If, for instance, the second price information unit 18 is encumbered with an error or fault, this unit will send no response signal, and hence the time slot between the first and the second response signals will be twice as long, wherein the communication unit is able to pass on this information to the main computer unit 10, so that the user obtains information to this effect and is able to rectify matters. Thus, the response signals obtained from the various price information units 18 may be mutually equal and of very short duration. This eliminates the need of particular identification codes for the various price information units 18. If, on the other hand, there is used a unique code for the store locality in the duodirectional communication, such that two price information systems of mutually the same kind installed in adjacent store localities will not influence one another. This would not be suitable, however. The construction of the price information unit 18 can be adapted to customer requirements. The majority of the electric functions of the price information unit 18 are integrated in one single circuit which comprises fewer components, and which can therefore be obtained at a low manufacturing price. Parts of the electric circuits of the price information unit 18 are only driven intermittently when communication with the units takes place, so as to save energy. When the price information unit 18 receives a so-called activating message, the unit switches to a state for continuous operation of these circuits. The bit speed of the message may, for instance, be 1/128 of the carrier wave and the degree of modulation is 1/64 of said carrier wave. Of course, other numerical devisors can be used with the characteristic of being multiples of two of the carrier wave.

The messages are transmitted sequentially to the price information units 18. An example of a communication procedure is given below. When the receiver of the price information units 18 is only driven intermittent¬ ly, a sequency start message is preceded by an activat¬ ing message, so as to obtain continuous operation of the receiver. Subsequent to the sequence start message, information is transmitted to all of the price informa¬ tion units 18. This information includes price informa¬ tion intended for that price information unit which stands in turn according to a predetermined order and an error check code configured so as to include the whole of the instant communication sequence. An example of the configuration of a message is given below. A- loop and B-loop form a loop pair. 1. Activating message

A-loop t B t B t B ... B-loop t B t B ... t-time interval B-shop code

This message is repeated until all of the price infor¬ mation units run continuously.

2. Sequence start message or message intended for all units.

A-loop T RHcC t RFcC

B-loop tRFcC tRFcC t-time interval R-order number in which price information units shall be started or information to the effect that the message is intended for all units.

If the message is intended for all units, the message is also stated.

H-information to the effect that it is a main mess¬ age.

F-information to the effect that it is an accom¬ panied message. c-message check code. The shop or store code is included as a part.

If the message is not intended for the shop, the code will not agree. C-whole sequence check code.

This message is always transmitted. Repetition can occur any desired number of times. 3. A-loop t IHcC tIFcC

B-loop t IFcC t IFcC

Response s s s s t-time interval

I-information to the price information unit con¬ cerning price, price configuration and whether a response is expected and what the response shall include. H-information disclosing that it is a main message. F-information disclosing that it is an accompanied message. c-message check code. The shop or store code is included as a part.

If the message is not intended for the shop or store, the code will not agree.

C-whole sequence check code. S-response is expected depending on the information under I.

This sequence is always transmitted. Repetition can be carried out any desired number of times.

The aforedescribed embodiment of the present invention merely constitutes an example of how the invention can be realized and is not limitive of the invention, the scope of which is defined in the following Claims.

Claims

1. An electronic price information system which com¬ prises a plurality of price information units (18) for displaying changeable information, a main computer unit (10) to which information is supplied and which com¬ municates with a communication unit (12) connected thereto, said communication unit, when desired, being connectable to any selected number of slave units (16), wherein duodirectional communication between, on the one hand, the communication unit (12) and/or the slave units (16) and, on the other hand, the price informa¬ tion units (18) is effected by wire-less inductive coupling, c h a r a c t e r i z e d in that the communication unit (12) includes conversion means which function to convert the information transmitted from the computer unit (10) to a sequence of messages, wherein each message is intended for a specific price information unit (18) , which is determined by the position or order of the message in the message sequence, and in that the price information unit (18) includes a receiving means (20) for receiving the whole of the message sequence and a detecting means (22) for detecting the message intended for said specific price information unit.

2. A system according to Claim 1, c h a r a c ¬ t e r i z e d in that each of the price information units (18) also includes a generating means (30) which functions to generate a response signal of short dura¬ tion when said detecting means (22) assigned to a specific price information unit (18) detects the mes¬ sage intended for said price information unit (18).

3. A system according to Claim 2, c h a r a c ¬ t e r i z e d in that each of the price information units (18) also includes a transmitter means (20) operative to transmit, inter alia, the response signal to the communication unit (12) and/or the slave units (16), via said wire-less inductive coupling, when detection and receipt of the message intended for a specific price information unit (18) has been effected by said price information unit (18), detecting means (22) and receiving means (20).

4. A system according to Claim 3, c h a r a c ¬ t e r i z e d in that the communication unit (12) includes identification means for identifying the price information unit (18) that has transmitted a given response signal, said identification being effected on the basis of the order number of said response signal in a sequence of mutually similar response signals transmitted by the price information units (18) which have received a message intended for each of said price information units (18), and time slots between consecu¬ tive response signals.

5. A system according to Claims 1-4, c h a r a c - t e r i z e d in that a loop pair (14) is connected to the communication unit (12); in that each of two loop pairs (14) is connected to a respective slave unit (16), wherein information changes from these units is effected in that a frequency modulated current supplied to any one of said loop pairs (14) will result in a magnetic field in the surroundings of the loop pair (14) which is proportional to the current.

6. A system according to Claims 1-5, c h a r a c ¬ t e r i z e d in that the receiver means (20) and the transmitter means (20) in each of the price information units (18) consists of a conduction loop to which current is supplied by induction.

7. A system according to Claims 1-6, c h a r a c ¬ t e r i z e d in that each of the price information units (18) also includes a decoder (26) for decoding the message intended for a specific price information unit (18), and further includes a reproduction unit (28) for reproducing the coded message concerning price information.

8. A system according to Claims 1-7, c h a r a c ¬ t e r i z e d in that all price information units (18) receive in parallel the total message sequence for the purpose of checking communication quality.