GB2247760A - Shelf edge labelling - Google Patents

Abstract

A shelf edge labelling system comprises a multiplicity of labels 20 each connected to one of a plurality of aisle nodes 18 which in turn are connected to a controller 10 via existing electrical mains wiring 16. The controller is programmed to send packets of information specific to one or a group of labels capable of interrogating the one or group of labels to ensure that the information has been properly received. <IMAGE>

Description

SHELF EDGE LABELLING This invention relates to improvements in shelf edge labelling particularly for stores such as supermarkets.

Labelling products in supermarkets with price information is complex task particularly when prices may need to change rapidly. Many larger chains of supermarkets employ a central computerised system which down loads price information to each store in the chain through, for example, a data communications network to an electonic point-of-sale cocontroller held in each store. However, getting the prices to the products still presents a problem. Applying a sticky label to each product is labour intensive and shelf edge labelling represents a preferred method if it can be rapidly and reliably carried out.

Previous proposals for updating shelf edge labels include: the provision of an in-store label printing facility; the use of infrared broadcasting to electronic shelf edge labels; or direct cabling where a hard wire local area network connects labels to a master controller.

None of these methods have proved satisfactory in practice for various reasons. In-store label printing involves the installation of a high volume graphics printer to generate conventional shelf edge labels. This is labour intensive, prone to human error, and involves a significant delay between receiving the information and the shelves actually having up dated labels. Furthermore it is difficult to achieve acceptable print quality without introducing very complex printer technology.

Infrared broadcasting to peg board labels is quite satisfactory owing to the relatively small number usually involved. However, broadcasting to shelf edge labels involves installing a large number of infrared transmitters distributed around the ceiling of the store hard wired to a controller. These transmitter would flood the store with price updates which would hopefully be received by the labels, but because the communications are one way only the only way to check this would be by manual observation.

Infrared has a high susceptibility to obstructions, human or otherwise. Furthermore the largest emitters of background infrared radiation are people and thus updates can only sensibly be carried out when stores are closed.

Direct cabling is prohibitively expensive and once installed is extremely inflexible effectively dictating store layout.

The invention seeks to provide an electronic shelf edge labelling system which is improved in the above respects.

According to the present invention there is provided a shelf edge labelling system which comprises a multiplicity of labels each connected to one of a plurality of aisle nodes which in turn are connected to a controller via the existing electrical mains wiring, the controller being programmed to send packets of information specific to one or a group of labels capable of interrogating the one or group of labels to ensure that the information has been properly received.

The labels are connected to the local or aisle node preferably by means of a four wire local area network which can be run, for example, along the shelf edges from label to label to the aisle node associated with the particular block of shelves. The aisle node is in turn connected to the electric mains, for example via a convenient electric socket or light socket. The controller may be the standard in-store computer controller currently used for price information with some additional software and an interface card enabling it to communicate with the aisle nodes and thus the labels. In one particular method of operation the controller broadcasts to all aisle nodes price information. The price data is identified in each case by a sixteen digit product code compressed to six bits per digit. Thus, only the label responding to this code will receive the price information and be updated.

Provision is made for acknowledgement signal to be sent to the controller from the label when information is correctly received. If a negative "NAK" is received the information is rebroadcast.

The aisle nodes may be micro-controllers and their function is data communication between the labels and the remote store computer controller. In addition they can provide power for the labels. A typically store would require 250 to 1000 aisle nodes each of which would be connected into the electrical mains network via a mains modem such as a current carrier transceiver using FSK signalling format to obtain physical access to the mains. Communication with the individual labels is via a four wire local area network driver and receiver such as an RS485 type communicator.

The mains ring is readily accessible from each store aisle via existing power cabling for lighting, freezers, and the like.

Bach "label" can be a 4-bit microcontroller capable of bidirectional data communication with the aisle node and driving aid display such as an LED or liquid crystal display. Preferably the label is provided with a serial EEPROM to increase the resilience of the system in the event of a power failure. This also makes the label relocatable, and will hold the most recent price, product code, and label address. The actual display itself needs to be low cost and have a low current requirement as well as a wide viewing angle and visibility in fluorescent tube lighting. The display should be capable of displaying at least four digits and be provided with a flashing dot for serial bar code display. A system for a typical supermarket would require a minimum of one label per store line typically ten to thirty thousand labels per store.

A high signal to noise ratio is achieved with low error probability by good analogue filtering of narrow band noise and impulse noise generated by other devices connected to the mains. This may be supplemented by additional digital filtering. A particular feature of the system of the invention is that correct receipt of price information is acknowledged. This is based on CRC error checking protocol, allowing extensive error recovery and good data through put which in turn allows bit rates to be kept low across the mains network. Typically the system operates at one kilobyte allowing information to be sent long distances, up to one kilometer without corruption.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which Figure 1 is a diagrammatic representation of the system; and Figure 2 is perspective view of a shelf edge label.

Referring to the drawings, a typical in-store system is illustrated in Figure 1 and comprises a master controller 10 which will, in most cases, be the computer already employed in a store such as a 4680 PC controller. This receives information from, e.g., head office typically via a leased telephone line 12 enabling the store to be provided with rapid price updates. The controller 10 includes an interface card 14 and is connected to the electric mains ring 16 via a suitable modem (not shown). A plurality of aisle nodes 18 are also connected to the mains ring 16 via modems and receive information broadcast from the controller 10. Each aisle node in turn is connected to a multiplicity of labels 20 via a four wire local area network system 22.

Each label 20 comprises a digital display 24 together with any desired indicia, e.g. product description, 26 amd preferably an LED 28 whose function will be described more fully hereinafter. Each label 20 is connected to the four wire LAN 22 and includes a microprocessor arranged for bidirectional data communication between the label and the aisle node, and a serial EEPROM.

The controller 10 is programmed to broadcast price information to be forwarded to one or more specific labels 20 to all aisle nodes 18 via the mains ring 16.

Particular items of price data are identified by a sixteen digit product code (ANA) compressed to six bits per digit in a randomly selected manner. The label having this product code "recognises" the information receives it and, if received correctly, acknowledges the fact whereafter the controller ceases broadcasting. If the information is not correctly received a NXK signal is sent back to the controller from the label and the information is rebroadcast. In this way errors are self corrected and there is no need for manual checking of label updates.

Furthermore updates can be carried out practically instantaneously on receipt of fresh price information via the telephone line 12 from head office.

The data is broadcast from the controller 10 in "packets" with each packet having a distinctive start pulse which the software aligns on. The data packet may be split into segments comprising a control portion, a type portion, a product code portion, a price information portion and an error checking portion. A typical data packet will be one hundred and thirty bits in length and at a twelve hundred baud five transmissions per second can be supported. This equates to eighteen thousand transmissions per hour and thus the entire number of labels in a large store could be completely updated within two hours. Typically, of course, a very much smaller number of updates will be required at any given time and these can be carried out in a few seconds.

In more detail and by way of example, the data packet transmitted over the mains from the controller 10 to the aisle nodes may comprise in turn a synchronisation field, an address field, a control field, a data field, a CRC error check field and finally an aisle node reply window.

The synchronisation field may consist of 8 bits of preamble and the start bit. The aisle node address field may consist of 12 bits. The control field may consist of 4 bits, the first 3 bits indicating packet type and the fourth bit data direction (i.e. controller to aisle node or aisle node to controller). The data field contains the information to be passed to the aisle LAN. The CRC may consist of 16 bits. The aisle node reply window makes two time slots available to the aisle nodes, one slot for an acknowledgement ACK signal and the other for a NAK signal.

The ACK is sent to the controller from the aisle node as a pulse of predetermined length. The window allows for up to 8 such pulses consecutively. Any aisle nodes that wish to send an ACK but which have detected a previous node sending one, do not need to reply. Only aisle nodes which have received acknowledgement from their label LAN need to send an ACK pulse. NAK pulses result from CRC failure, but if one node wishes to transmit a NAK pulse but has already detected one transmitted by another node, it does not send one. The packet is re-transmitted until no more NAK pulses are received by the controller 10. If neither an ACK nor a NAK pulse is received by the controller in the respective time slots, then after a time-out period the packet is retransmitted.Collision is avoided by waiting a variable time delay before retransmission, this delay being a random number of bits based on the unique address of the aisle node.

The packet transmitted over the aisle LAN 22 from the aisle node to labels may comprise in turn a synchronisation pulse, an ANA code, a control field, a data field, a CRC field and a label reply window. The ANA code identifies the product, so that labels at different shelf locations but for the same product can be addressed simultaneously.

The control field may consist of 4 bits defining packet type. The data field consists of 4 or 5 digits of price information to be displayed on the label. The CRC field provides a 16 bit cyclic redundancy check for error detection. The label window defines respective time slots for ACK and NAK pulses. Both the transmit and receive lines are normally pulled high. During the ACK slotany label may pull its transmit line low to give a pulse of predetermined width: the same is true of the NAK slot.

Finally, there is the time-out slot: if a label times-out on data recetion it waits for the next label reply window and returns a time-out pulse in this slot, to initiate retransmission of the previous packet. If no time-out pulse is detected, this slot is made available for a hand held terminal stock control information packet.

All packets are self-aligning on the mains and aisle networks, by use of the synchronisation pulses at the start of each packet.

The LED 28 is designed to be used with a hand held terminal 30 for stock taking. Led 28, depending on bias, can receive or transit information. When transmitting it may transmit, for example, the serial bar code of the product which can be "read" by the hand held terminal 30. The operator may manually count the number of items present on the shelf and input this number with the bar code into the memory of the terminal 30. This information can later be downloaded and compared with the stock control information held within the central controller 10. In the "receive" mode the LED 28 can receive information direct from the hand held terminal 30.

Claims (11)

1. A shelf edge labelling system which comprises a multiplicity of labels each connected to one of a plurality of aisle nodes which in turn are connected to a controller via the existing electrical mains wiring, the controller being programmed to send packets of information specific to one or a group of labels capable of interrogating the one or group of labels to ensure that the information has been properly received.

2. A system as claimed in claim 1 in which the labels are connected to the local or aisle node by means of a four wire local area network.

3. A system as claimed in claim 2 in which the four wire local area network is run along the shelf edges from label to label to the aisle node associated with the particular block of shelves.

4. A system as claimed in any of claims 1 to 3 in which the aisle node is connected to the electric mains via a convenient electric socket or light socket.

5. A system as claimed in any of claims 1 to 4 in which the controller is the standard in-store computer controller used for price information having additional software and an interface card enabling it to communicate with the aisle nodes and thus the labels.

6. A system as claimed in any of claims 1 to 4 in which the aisle nodes are micro-controllers and their function is data communncation between the labels and the remote store computer controller.

7. A system as claimed in any of claims 1 to 6 wherein 250 to 1000 aisle nodes are provided each of which is connected to the electrical mains network via a mains modem.

8. A system as claimed in claim 7 in which the mains modem is current carrier transceiver using an FSK signalling format to obtain physical access to the mains.

9. A system as claimed in any of claims 1 to 8 wherein each label is a 4-bit microcontroller capable of bidirectional data communication with the aisle node and driving aid display being an LED or liquid crystal display.

10. A system as claimed in claim 9 wherein the label is provided with a serial EEPROM to increase the resilience of the system in the event of power failure.

11. A system as claimed in any of claims 1 to 10 wherein one label per store line is provided.