Abstract:
A material handling system and method of automatic address assignment of components of the material handling system, includes a conveying surface divided into a plurality of zones, a plurality of motors propelling each zone, a plurality of lower level controllers and a plurality of sensors adapted to communicate the presence of an article on the conveying surface to the associated lower level controller. An upper-level controller in communication with the lower level controllers assigns a unique communications address to a specific lower level controller identified by a reference article being detected by the sensor with that lower level controller.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority from U.S. provisional patent application Ser. No. 60/663,032, filed on Mar. 18, 2005, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates generally to material handling systems having address-based networks, and more particularly to automatic address assignment in the material handling system network.  
         [0003]     Conveyor systems are used in a wide variety of material handling applications. These include such things as conveying luggage throughout airports, conveying parcels through transportation terminals, conveying manufactured parts or components throughout factories, conveying inventory, sorting and conveying items to be transported, and various other applications. Such material handling systems may use conveyors having endless belts that are rotated around end rollers to cause the top surface of the belt to move in the direction of conveyance. Such material handling systems alternatively may use conveyors having a series of rollers, selected ones of which are driven to cause articles positioned on the rollers to move in the direction of conveyance. An example of one such roller conveyor is disclosed in U.S. Pat. No. 6,253,909 issued to Kalm et al., entitled MODULAR POWER ROLLER CONVEYOR, the disclosure of which is hereby incorporated herein by reference. Still other types of conveyors may use movable slats to transport articles, as well as other structures.  
         [0004]     The installation and commissioning of prior material handling systems is a time consuming labor-intensive process. The design and installation of prior material handling systems has often involved a great deal of custom engineering of the system in order to make the system match the physical layout of the customer&#39;s site, as well as match the conveying needs of the customer. Such custom engineering not only includes the physical aspects of the individual conveyors making up the system, but also the programming and control logic that is used to control the overall system.  
         [0005]     The assignment of addresses to devices of the network is currently a labor intensive means. A conventional system may utilize physically setting the addresses of each device, for example, with a dip switch. The process becomes time consuming and cumbersome with material handling systems that have a greater number of components and devices or are physically larger and more complex.  
         [0006]     Reducing material costs, the amount of time and labor involved in these tasks is highly desirable. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a block diagram showing a material handling system; and  
         [0008]      FIG. 2  is a flowchart illustrating addressing of devices of the material handling system in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0009]     Referring now to the drawings and the illustrative embodiments depicted therein, a material handling system  110  illustrates the assignment of communication addresses to lower level, or slave, controllers  32   a - 32   g  from an upper level, or master, controller  118  over an address-based network. The upper level controller may be an inventory management control and the lower level controllers may be bed level controllers, such as disclosed in commonly assigned patent application Ser. No. 10/764,962, filed Jan. 26, 2004 (claiming priority from U.S. application Ser. No. 60/442,311, filed on Jan. 24, 2003) by Siemens, for an INTEGRATED CONVEYOR BED, and published PCT Application No. WO2003PO2881 for an INTEGRATED CONVEYOR BED, filed on Jan. 24, 2003, the disclosures of which are hereby incorporated herein ( FIG. 1 ). Network  22  may be wired, optical or wireless, such as radio frequency, infrared, or the like. Alternatively, the upper level controller may be a conveyor bed level controller and the lower level controllers may include brushless motor controllers, motor device controllers, and the like. Other configurations may be apparent to the skilled artisan.  
         [0010]     In order to assign communication addresses from master controller  118  to a plurality of slave controllers, such as lower level controllers  32   a - 32   g , over an address-based network  22 , only one lower level controller  32   a - 32   g  responds to a particular address sent by master controller  118 . The difficulty is that, initially, none of lower level controllers  32   a - 32   g  has a unique communication address assigned to it. Moreover, it is necessary that the particular lower level controller  32  receiving an address be physically associated to the layout of conveyor system  110  in the memory of master controller  118 . This may be accomplished by an automated address assignment procedure  200 , diagramed in  FIG. 2 . Automated address assignment procedure  200  replaces the manual procedure of setting addresses, such as using dip switches, hand held computers, or the like. The process of manually setting addresses is time consuming and cumbersome, especially in material handling systems that are large and complex.  
         [0011]     Automated address assignment procedure  200  uses a reference device  116 , such as a reference package to assist auto addressing of lower level controllers  32   a - 32   g . Lower level controllers  32   a - 32   g  communicate with upper level controller  118  over a network  22 . Network  22  may be a standard and commonly available high-speed serial or parallel network, including but not limited to: Ethernet, DeviceNet, ControlNet, Firewire, CanOpen, or FieldBus. Network  22  may optionally include a bridge (not shown) translating between different of the above standard or other protocols. Automated address assignment procedure  200  uses associated sensors  112   a - 112   g  for each zone  16   a - 16   g . Sensors  112   a - 112   g  detect the presence of an object in each zone  16   a - 16   g  associated with particular lower level controllers  32   a - 32   g . Sensors  112   a - 112   g  may be photosensors, proximity sensors, cameras, mechanical switches, or the like. Zones  16   a - 16   g  are illustrated as a section of conveyor. Reference package  116  may be an item, or article, that will be of the type normally transported on the material handling system or a specific object dedicated for use only in address assignment. Reference package  116  is capable of detection by sensors  112   a - 112   g  when it goes through material handling system  110 .  
         [0012]     Automated address assignment procedure  200  begins with upper level central controller  118  setting all the devices, such as lower level controllers  32   a - 32   g , on network  22  to a reset or idle state in step  210  unless the devices are already set to an idle state. The state allows the address registers of inactivated lower level controllers  32   a - 32   g  to be clear when the addressing process begins and, therefore, ready to accept an address assigned by central controller  118 .  
         [0013]     The material handling system is activated at step  212  for material handling path  120 . Reference package  116  is placed at the beginning of material handling system  110  at step  214  to travel through the material handling system path  120 . The process for a straight system will be discussed first. Discussion of a material handling system with multiple paths will be discussed later. However, is should be noted, the procedure may be applied to a plurality of configurations and types of material handling systems, such as a curved conveyor  122 , and the like.  
         [0014]     When reference package  116  reaches first sensor  112   a , sensor  112   a  detects the presence of reference package  116  at step  216 . The activation of first sensor  112   a  triggers communications with associated lower level controller  32   a  of the presence of reference package  116  at step  218 . Associated lower level controller  32  is placed in an acceptance mode state and then informs central upper level controller  118  of the presence of reference package  116  at step  220 .  
         [0015]     Central controller  118  may have a read/write memory device where address assignments may be stored and accessed in a database or table. Central upper level controller checks the memory device for the next open address to be assigned, generally in a sequential order at  222  according to the topology of the system layout. Central controller  118  then sends out the address assignment signal to lower level controller  32   a  associated with activated sensor  112   a , at step  222 . The address assignment signal is accepted by the lower level controller  32   a  in the acceptance mode state as a result of reference package  116  being detected, and no other corresponding lower level controllers will respond to the address assignment. The associated lower level controller  32   a  is thus activated with the new address assignment.  
         [0016]     As reference package  116  proceeds through path  120  of material handling system  110 , address assignment process  200  waits for another sensor to be detected at step  226 . If no sensor is activated, the process may default and move on to steps  228  and  230 . Process  200  may move to step  230  with an end message that may be triggered by such events as expiration of a certain length of time, when the number of devices to be addressed has been met, or having the last device identify itself as the last device along paths  120 ,  122 . However, if another sensor  112   b  is activated by detection of reference package  116 , process  200  returns to step  218  and repeats for addressing of lower level controller  32   b . This is repeated until all lower level controllers have addresses assigned.  
         [0017]     The system and method may also be utilized in material handling systems with multiple alternative paths, configurations or loops. After path  120  is complete, the reference package may be placed in another path  122  to be addressed. Second path  122  may be activated by diverter  124  or any other conveying transfer or diverting device. Automated addressing assignment procedure  200  first completes addressing of first path  120  and then continues to step  228 , where central upper level controller  118  inquires if another path or loop with additional devices requires addressing. If another path requires addressing at step  228 , the process returns to step  212  for activation of second path  122 . Paths  120  and  122  of  FIG. 1  share same first device  32   a , for which central controller  206  keeps the same first assigned address. As reference package  116  travels on second path  122 , central controller  118  anticipates the next device to read the second assigned address after the first assigned address from path  120 . However, when central controller  118  detects a new zone  16   e  by receiving an idle or reset state message from lower level controller  32   e  of path  122 , process  200  determines that another path or loop exists in material handling system  110 . Central controller  118  then assigns the next available address assignment to lower level controller  32   e  of path  122 . Central controller  118  maintains the addresses of first path  120  and records the new addresses for second path  122  in the read/write memory. Process  200  then continues until lower level controllers  32   f  and  32   g  of zones  16   f  and  16   g  are addressed. In this example, when reference package  116  reaches zone  16   d , central controller  118  recognizes a return to path  120  and that zone  16   d  is the last zone of material handling system  110 .  
         [0018]     Automated address assignment procedure  200  does not require a separate communications connection between controllers to control address assignments and, therefore, may be used in a master/slave configuration. Automated address assignment procedure  200  may provide a basic layout of the material handling system based on the relationship of addresses of lower level controllers  32   a - 32   g , which are generally assigned in a sequential order. For example, basic layout for material handling system  110  can be obtained from the address assignments of paths  120  and  122  of  FIG. 1 . Path  120  is illustrated as including four material handling zones  16   a - 16   d  and address assignment of path  122  is illustrated as including three material handling zones  16   e - 16   g  where path  122  starts after first zone  16   a  and ending before last zone  16   d , thus a basic layout can be produced showing the relationship of all zones  16 - 16   g  relative to one another. The topology of the material handling system may be discovered by using a topology detection technique with a master controller, as disclosed in commonly assigned patent application Ser. No. 60/566,470, filed Apr. 29, 2004, by Siemens, for a NETWORK TOPOLOGY DISCOVERY, the disclosure of which is hereby incorporated herein. Furthermore, the system and method of the present invention may also address material handling systems with zones with a plurality of devices in each zone.  
         [0019]     An embodiment of the invention provides a method and system for addressing devices on a network, which is simpler and automatic with a reduction in time and labor. Changes and modifications in the specifically described embodiment can be carried out without departing from the principles of the invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law.