Abstract:
A method of changing a display sequence of an electronic price label which uses two commands to add and remove information from a display sequence. The method includes the steps of formulating a change sequence message including a number of change sequence commands which reference memory registers of the electronic price label, and sending the change sequence message to the electronic price label. An Add command causes the electronic price label to additionally display data in a predetermined memory register. A Remove command causes the electronic price label to stop displaying data in a predetermined memory register. If data accompanies an Add command, the method further determines whether such data will overwrite existing data in the predetermined memory register, and if it will, stores the existing data for later retrieval.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electronic price label (EPL) systems, and more specifically to a method of changing an EPL display sequence. 
     EPL systems typically include a plurality of EPLs for merchandise items in a transaction establishment. EPLs typically display the price of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. A transaction establishment may contain thousands of EPLs to display the prices of the merchandise items. The EPLs are coupled to a central server from where information about the EPLs is typically maintained in an EPL data file. Price information displayed by the EPLs is obtained from a price look-up (PLU) data file and stored within an EPL price change record. 
     EPLs are also being used to display more than just price information. Retailers are using EPLs to display promotional information in order to more effectively market associated merchandise items. During off-peak hours, retailers display inventory and status information for the benefit of employees. EPLs may be programmed to display more than one type of information in sequences using flashing and scheduling techniques. 
     However, EPLs have limited memory capacity for storing the many types of information which must be displayed. For example, a typical EPL has four data registers which can simultaneously store, at most, two types of information. Therefore, it would be desirable for providing a method of changing display sequences despite the memory capacity limitation of an EPL. 
     SUMMARY OF THE INVENTION 
     In accordance with the teachings of the present invention, a method of changing an EPL display sequence is provided. 
     The method includes the steps of formulating a change sequence message including a number of change sequence commands which reference memory registers of the electronic price label, and sending the change sequence message to the electronic price label. 
     An Add command causes the electronic price label to additionally display data in a predetermined memory register. A Remove command causes the electronic price label to stop displaying data in a predetermined memory register. If data accompanies an Add command, the method further determines whether such data will overwrite existing data in the predetermined memory register, and if it will, stores the existing data for later retrieval. 
     The electronic price label system includes an electronic price label including a memory, and a computer. The computer formulates a change sequence message including a number of change sequence commands which reference memory registers of the electronic price label, and sends the change sequence message to the electronic price label. The available change sequence commands include a first command which causes the electronic price label to additionally display first data in a first memory register and a second command which causes the electronic price label to stop displaying second data in a second memory register. 
     It is accordingly an object of the present invention to provide a method of changing an EPL display sequence. 
     It is another object of the present invention to provide a method of temporarily changing an EPL display sequence. 
     It is another object of the present invention to add display information to a display sequence. 
     It is another object of the present invention to add display information not already in memory to a display sequence. 
     It is another object of the present invention to remove display information from a display sequence. 
     It is another object of the present invention to provide a method of displaying a different type of information under a display sequence using a limited amount of memory. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings, in which: 
     FIG.  1 . is a block diagram of a transaction processing system; and 
     FIGS. 2A and 2B form a flow diagram illustrating a sequence management method. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, a first embodiment of transaction system  10  primarily includes host computer system  12 , point-of-sale (POS) system  14 , and EPL system  16 . Here, components  12 ,  14 , and  16  are shown as separate components that are networked together, but they may also be combined in different ways to form less components. Thus, host computer system  12  may be a POS terminal which doubles as a host computer for network of other POS terminals. Also, host computer system  12  and EPL system  16  may be combined into a single system. 
     POS system  14  includes bar code reader  18  and terminal  20 . 
     EPL system  16  primarily includes EPLs  22 , host EPL terminal  24 , and EPL storage medium  26 . 
     EPLs  22  include control circuitry  52 , data memory  54  and displays  56 . 
     Control circuitry  52  receives and transmits messages from EPL terminal  24  and controls display of information by display  56 . Control circuitry  52  stores data and instructions within the messages. For example, control circuitry  52  stores price and promotional information in memory  54 . Control circuitry also stores display sequence information in memory  54  and responds to basic control instructions, including instructions to add or remove display information from a display sequence. 
     Host EPL terminal  24  executes EPL software  30 . To assist with execution of certain tasks performed by EPL software  30 , EPL terminal  24  includes a built-in time keeping device, commonly referred to as a system clock, which is synchronized with current time, in order to automatically execute the tasks at their scheduled times. 
     EPL software  30  is responsible for scheduling and transmitting data to EPLs  22 . EPL software  30  obtains prices in price look-up (PLU) data file. 
     Host EPL terminal  24  also executes sequence management software  34  which manages display sequence changes. A display sequence instruction tells EPL  22 s to display the contents of memory registers identified in the sequence instruction. Under the present invention, sequence management software  34  automatically or in response to operator-initiated commands changes display sequences. For example, the message may include an instruction to cause EPL  22  to alternatingly flash price information and promotional information in accordance with a new display sequence. Sequence management software  34  may additionally send display data to the extent that a display sequence change calls for display data, e.g. promotional information, which is not already in memory  54 . 
     EPL storage medium  26  stores EPL data file  32  sequence data file  36 . EPL storage medium  26  and is preferably a fixed disk drive. 
     EPL data file  32  contains EPL identification and checksum information. Checksum information is calculated from price information in PLU data file  46 . EPL data file  32  identifies information that is currently stored and displayed by EPLs  22 , including memory register information. 
     Host computer system  12  includes PLU storage medium  44 , transaction server  42 , and input device  40 . 
     Transaction server  42  handles price requests from POS terminal  20 . POS terminal  20  sends item identification information to transaction server  42  and transaction server  42  returns the corresponding price from PLU data file  46 . 
     PLU storage medium  44  stores PLU data file  46 . PLU data file  46  is available for distribution to POS terminal  20 . Provision may be made for direct access to PLU data file  46  by bar code reader  18 . 
     Turning now to FIGS. 2A and 2B, a sequence management method is illustrated beginning with START  60 . 
     In step  62 , sequence management software  34  formulates a change sequence message. The change sequence message could be a broadcast message addressed to all EPLs  22  or an individual message addressed to a single EPL  22 . 
     If the message requires data to be displayed that is not already being displayed, then sequence management software  34  includes an Add command in the message. If the message requires data to be displayed that is not already stored within EPLs  22 , then sequence management software  34  retrieves the data from its data source and places it in the message with the Add command. Similarly, if the message requires data to no longer be displayed, then sequence management software  34  includes a Remove command. More than one command may be included in a message. 
     In step  64 , sequence management software  34  waits for an indication to have EPL software  30  send the change sequence message. The indication may come from its own internal scheduler (automatic operation) or from operator action (manual operation) following formulation of the message. 
     If the change sequence message must be sent, steps  66 - 82  are implemented prior to sending. Sequence management software  34  examines the change sequence message for overwritten data and stores any overwritten data and the current display sequence in sequence data file  36 . 
     In step  66 , sequence management software  34  identifies a target EPL  22  in EPL data file  32 . 
     In step  68 , sequence management software  34  identifies commands within the change sequence message. 
     In step  70 , sequence management software  34  determines whether the sequence change involves any Add commands and associated data. If so, operation proceeds to step  72 . If not, no data will be overwritten and operation proceeds to step  80  to check for another EPL  22 . 
     In steps  72 - 78 , sequence management software  34  determines whether the sequence change will overwrite data currently in memory  54 . Overwriting of data occurs when the change sequence message contains an Add command whose location argument points to a location in memory  54  which currently contains data and new data accompanies the Add command. 
     In step  72 , sequence management software  34  determines the memory  54  location associated with an Add command. 
     In step  74 , sequence management software  34  determines by reading EPL data file  32  whether that memory location is currently empty. If so, data will not be overwritten and operation proceeds to step  76  to check for another Add command. If not, data will be overwritten and operation proceeds to step  76 . 
     In step  76 , sequence management software  34  stores current memory contents in sequence data file  36 . 
     In step  78 , sequence management software  34  determines whether the Add command with data is the last Add command with data. If so, operation proceeds to step  80 . If not, operation returns to step  72 . 
     In step  80 , sequence management software  34  determines whether the EPL is the last EPL. If so, operation proceeds to step  82 . If not, operation returns to step  66 . 
     In step  82 , sequence management software  34  stores the current display sequence in sequence data file  36 . The current display sequence may be retrieved and implemented in another change sequence message if the new display sequence is a temporary display sequence. 
     In step  84 , sequence management software  34  sends the change sequence message. The message may be a broadcast message or an individually-addressed message and operation ends at step  86 . 
     For example, suppose that a first display sequence for a target EPL  22  includes only price information from a first register in memory  54 . Suppose that a new display sequence adds a promotional message to the display sequence. If the promotional information is not stored within memory  54 , then a change sequence message to EPL  22  would contain the promotional information, instructions for storing the promotional information in a second memory  54  register, and an Add command pointing to the second memory  54  register. The change sequence message could have additional instructions, such as flashing instructions. If the promotional information is already stored within the second memory  54  register, then the change sequence message would only require the Add command. 
     As another example, suppose that a first display sequence for a target EPL  22  includes three types of display information: price information, a first promotional message (e.g., “SALE”), and a second promotional message (e.g., “SAVE 0.40”). The display sequence includes instructions for displaying the three types of information. In order to replace the first promotional message with a third promotional message, sequence management software  34  would send a change sequence message containing an Add command which references a memory location where the first promotional message is stored, the third promotional message, and instructions for storing the third promotional message in the memory location. The first promotional message is overwritten by the third promotional message. Therefore, sequence management software  34  stores the first promotional message in sequence data file  36 . 
     Advantageously, the method of the present minimizes storage problems in EPLs  22  having limited memory capacity. EPLs  22  may quickly return to a current display sequence following a temporary display sequence. 
     Although the present invention has been described with particular reference to certain preferred embodiments thereof, variations and modifications of the present invention can be effected within the spirit and scope of the following claims.