Patent Publication Number: US-11033151-B2

Title: Modular holding bin having individually configurable food holding modules

Description:
FIELD OF THE INVENTION 
     The present disclosure generally relates to systems and methods for controlling module holding bins used in a food facility and, more particularly, to controlling a discovery mode for identifying holding modules in a modular holding bin. 
     BACKGROUND 
     The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventor(s), to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
     Food warming units, which are also known as food holding ovens or food holding bins, are used in the food industry to keep pre-cooked foods hot until they are used. Such ovens and food warming apparatus allow precooked food items to be stored separately until needed. By way of example, when a fast-food restaurant receives an order for a sandwich, the sandwich is typically assembled on a food preparation table where the contents of certain sandwich items, a hamburger patty for example, can be removed from food warning units. Storing precooked foods in food warming units thus enables quick sandwich assembly and efficient order fulfillment. 
     Prior art food holding ovens come in various fixed sizes but are not reconfigurable once they are installed. Such fixed-sized units thus limit food preparation layouts, which may change over time or have to be modified or altered for numerous reasons. For example, as restaurants add or change menus items, food preparation layouts might need to be adjusted. Fixed dimensional heating units limit the degree to which the food preparation layouts may be reconfigured. 
     Similarly, when a restaurant kitchen is remodeled existing fixed ovens and food warming apparatus might not be properly sized for the reconfigured kitchen. This can necessitate having to purchase one or more new ovens or warming apparatus at considerable expense or necessitate an undesirable or inefficient kitchen layout. Current food holding bins/ovens and warming units are not reconfigurable. A need exists for a more flexible apparatus. 
     As food warming units are deployed in increasing numbers, power outages have become a problem, especially in geographic locations where power grid infrastructure is lacking. In some locations around the world, fast-food restaurants can experience multiple power outages in a day. Each power outage has the potential of destroying food. When the power goes out, the holding modules heating food stop working, and the food can spoil as a result. 
     Another issue facing food warming units is the prevalence of these units across wide geographic expanses and the lack of remote access to these units. The result is that any time substantial modifications need to be made to a food warming unit, a technician must come out and physically modified the unit on the spot. There is no ability to provide a streamlined centralized programming functionality. 
     SUMMARY OF THE INVENTION 
     In accordance with an example, a modular food holding bin apparatus comprises: a plurality of individually controllable and individually configurable food holding units located at respective physical locations in the modular food holding bin apparatus, and a master controller coupled to each of the plurality of food holding units via a communication bus architecture, the communication bus architecture having a multi-master, multi-point communication protocol to allow for bi-directional communication on the bus architecture between the master controller and each of the plurality of food holding units, the master controller having one or more processors and one or more non-transitory computer readable memories. The master controller may be configured to (i) transmit an interrogation message on a line conductor that extends between the master controller and a first physical location of the physical locations in the modular food holding bin apparatus, wherein a first food holding unit from the plurality of food holding units is located at the first physical location, wherein the first food holding unit is configured to detect the interrogation message and, in response to detecting the interrogation message, transmit an address request message onto a first bus to the master controller, the first bus being a first bus of the communication bus architecture extending from the master controller to a first at least a plurality of the physical locations in the modular food holding bin apparatus including the first physical location, the first at least a plurality of the physical locations including the first physical location, (ii) determine an address assignment for the first food holding unit at the first physical location, in response to receiving the address request message, and (iii) transmit, via the first bus and to the first food holding unit, an address assignment message to enable the first food holding unit to thereafter selectively communicate with the master controller. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  illustrates a modular holding bin with four modular holding units; 
         FIG. 2  illustrates modular holding units in various different positions for an unassembled modular holding bin; 
         FIG. 3  depicts several modular holding units operatively coupled to a master controller through a network that comprises other modular holding units, communications busses and single, interrogation wires that extend between physically-adjacent devices; 
         FIG. 4  is a block diagram of a master controller for a modular holding bin; 
         FIG. 5  is a block diagram of a modular food holding unit within a modular holding bin; 
         FIG. 6  is a block diagram of an expansion control unit, which enables the master controller to communicate with food holding units in different columns; 
         FIG. 7  is a flowchart of a method for controlling a modular food holding bin, such as the one shown in  FIGS. 1 and 2 ; 
         FIG. 8  is a block diagram of a power recovery module as may be implemented by the master controller of  FIG. 4 ; and 
         FIG. 9  is a flowchart of a method for power recovery for a modular holding bin. 
         FIG. 10  is a diagram of a network architecture that includes a central server station and a plurality of user stations and module holding bins, where the user stations are able to provide tunable parameters to the module holding bins. 
         FIG. 11  is a block diagram of an example user station from the network architecture of  FIG. 11 . 
         FIGS. 12-14  illustrate example graphical user interfaces for different tunable parameters (general parameters, diagnostic test bypass parameters, and diagnostic test parameters, respectively). 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a modular holding bin  100 , which is an example device that includes a first base unit  104 , a second base unit  105 , a first top cover  106 , a second top cover  107  and four modular holding units  108 ,  110 ,  112 , and  114 . The modular holding units  108 ,  110 ,  112 , and  114  are also referred to interchangeably herein as food holding bins or holding modules and heating modules and heating units. A modular heating bin contains one or more of these heating units in various stacked columns and/or rows, depending on the configuration. While the phrase heating unit is used in examples herein, as an example of a holding module, any uses of the term heating unit herein shall include holding modules, toasting units, and refrigeration units. 
     Two food holding units  108 ,  112  on the left-hand side are vertically stacked. Of the two food holding units  108 ,  112  on the left-hand side, the lower one of them (food holding unit  112 ) is stacked above and attached to the first base unit  104 . 
     Two food holding units  110 ,  114  on the right-hand side are vertically stacked. Of the two food holding units  110 ,  114  on the right-hand side, the lower one of them (food holding unit  114 ) is stacked above and attached to the second base unit  105 . 
     The food holding units  108 ,  110 ,  112 , and  114  may be functionally equivalent to prior food holding cabinets in the sense that they provide heat energy to pre-cooked food products placed into the food holding units. Other example food holding units are described in U.S. application Ser. No. 14/278,549, entitled, “Modular Food Holding Cabinet Having Individual Configurable Food Holding Units,” filed May 15, 2014, the entire disclosure of which is hereby incorporated by reference. The food holding units  108 ,  110 ,  112 ,  114  are therefore electrically and mechanically connected to a base unit and covered. More particularly, food holding units  108  and  112  are connected to base unit  104 ; food holding units  110  and  114  are connected to base unit  105 . Food holding units  108  and  112  are covered by the first cover  106 ; food holding units  110  and  114  are “covered” by the second top cover  107 . As shown in  FIG. 2 , however, the food holding units can be physically disconnected from each other and reconnected in different configurations. Of the many differences between the food holding units  108 - 114  and previous food holding units, differences based on an entirely new bus protocol and architecture, the food holding units each include a touchscreen display to the right of the holding region configured to receive a slidable food container. Each touchscreen display can be used to depict instruction signals to an operator, and each touchscreen display can be depressed to activate certain functions, for example, to activate a timer for the holding unit. 
       FIG. 2  is a partially exploded view of the modular holding bin  100  shown in  FIG. 1 .  FIG. 2  illustrates what is referred to herein as a “2×2” arrangement of four food holding units  108 ,  110 ,  112 , and  114 . 
     The four modular heating bins  108 ,  110 ,  112 , and  114  can be disconnected and reconnected to each other in different physical configurations yet have each unit retain different corresponding functionalities, so long as their configuration provides an electrical pathway through at least one unit  108 ,  110 ,  112 ,  114  to a master controller located in the base unit  104 . By way of example, the units can be arranged as shown in  FIG. 1  with two columns and two rows of modular heating bins. Four units can also be arranged such that there is one column of four, vertically-stacked modules or one horizontal row of four, horizontally-aligned modules. Four units can also be arranged such that there is a one column of three modules stacked vertically and one module in another column. With the bus protocols herein, any configuration of units/modules may be used across columns and rows. Other numbers of units/modules can be arranged in different configurations as long as they are all linked to the base unit  104 , for example, 2, 4, 6, 8, or greater numbers of units/modules, and including odd numbers of units as well. 
     The food holding units  108 ,  110 ,  112 ,  114  are individually addressable and individually controllable from the base unit  104  in the modular holding bin  100 . The individual addressability and individual controllability is provided by a unique network  300  that connects the food holding units  108 ,  110 ,  112 ,  114  to the base unit  104 . The topology of the network  300  is depicted in  FIG. 3 . 
     As used herein, the term bus refers to a conductor, or group of electrically-parallel conductors, that serves as a common connection for two or more circuits. 
     The modular heating units herein may employ a multi-master, multi-point communication bus protocol to form the system bus and the peripheral busses  1 -N, described herein. An example multi-master bus is the so called Controller Area Network (also termed herein “CAN”). CAN is a bus-based standard (or protocol) that allows devices, including microcontroller devices to communicate over a bus. Example CAN versions include CAN 2.0A and CAN 2.0B (available from Bosch corporation), which collectively describe Open System Interconnection (OSI) layers from the physical layer to the application layer, and which are also described in International Organization for Standardization (ISO) standard ISO 11898, which includes so called high speed CAN and low speed CAN implementations, among other descriptions. As used in the present description, references to a communication bus shall include a CAN communication network bus. 
     The CAN bus uses a two differential signal inputs (“CAN high” &amp; “CAN low” signal inputs). These differential signal inputs aid in reducing electrical signal noise inherent in the system to coupling on to the CAN bus. In addition, the topology of the CAN bus allows any device to talk on the bus at any time, in part because of the multi-master bus architecture of a CAN bus communication. The CAN busses, as further described below, may include a CAN system communication bus between a master base controller and expansion bases. The CAN busses may further include at least one CAN peripheral communication bus for each column (referred to as peripheral busses  1  through N, where N refers to the number of peripheral busses (columns) in the system which is a design choice). Given the multi-master bus architecture, any device on any of the CAN system communication bus or any CAN peripheral communication bus can talk on the bus and/or can provide master control, to varying degrees depending on unit programming, over the system. 
     Referring now to  FIG. 3 , the network  300  comprises a master controller  302  (also termed a “master base controller” or a “main base controller”) operatively connected to a matrix of “slave” food holding units that can be arranged in columns and rows as shown in  FIG. 2 . In  FIG. 3 , food holding units  304 A,  306 A and  308 A as well as the master controller food holding unit  302 , comprise a first vertical “column”  310  of units stacked on top of each other. Units  304 A,  306 A and  308 A are physically supported by and electrically coupled to the master controller  302 . 
     The food holding units  304 A,  306 A and  308 A are communicatively coupled to the master controller  302  by way of a “peripheral” communication bus  312  that extends between the master controller  302  and the food holding units  304 A,  306 A and  308 A. In addition to being coupled to the master controller by the bus  312 , the first unit  304 A is also coupled to the master controller through an interrogation signal wire  330 - 1 . The interrogation signal wires are used during an initial power on mode of the holding bin  100  to dynamically identifying the connected holding units and provide those uses with addresses for use in communication with the master controller. Upon an initial power on of the holding bin  100 , a signal is sent on the interrogation signal wire and that signal is detected by a food holding unit to which the wire is connected. The reception or detection of a “signal” on the wires  330 - 1 - 330 - n , gives permission to the food holding unit receiving the signal to respond by sending responses messages onto a peripheral communication bus to which the food holding unit is connected, e.g., the peripheral bus  312 . In power on mode, for example, the master controller  302  sends an interrogation signal on the wire  330 - 1  to the holding unit  304 A, after which the holding unit  304 A transmits onto the communication bus a request signal to the main base controller, e.g., master controller  302 , that the food holding unit to which the interrogation signal wire is attached, is waiting for an address to be assigned to it by the main base controller. 
     Still referring to  FIG. 3 , the second food holding unit  306 A in the first column  310  is coupled to the first food holding unit  304 A through a second interrogation signal wire  330 - 2 . The third unit  308 A in the first column  310  is coupled to the second unit  306 A through a third interrogation signal wire  330 - 3 . The signal wires  330 - 1 ,  330 - 2  and  330 - 3  are not connected to each other but, in the illustrated example, extend only between adjacent food holding units as shown in  FIG. 3 . The column  310  (as well as the other columns) is shown in  FIG. 3  as extending upward, indicating that additional holding units may be positioned in any one or more rows. 
       FIG. 3  also shows a single horizontal row  305  of expansion base control units  318  and  320 , which are laterally-adjacent to the master controller  302  and coupled to the master controller  302  via a communications bus  322 , which extends between only the master controller  302  and the expansion control units  318 ,  320 . This will form the “system” communication bus. The peripheral bus  312  expands in length as additional holding units are attached along a give column. Similarly, the system bus  322  expands in length as more expansion base control units are attached to the control row. The expansion control units  312  and  320  serve as “slave” control units to the master controller  302 . 
     In addition to being coupled to the master controller  302  via a systems communications bus  322 , the “first” expansion base control unit  318  is coupled to the master controller  302  by way of an interrogation signal wire  330 - 4  that extends between only the master controller  302  and the first expansion base control unit  318 . A second interrogation signal wire  330 - 5  extends between the first expansion base control unit  318  and the second expansion base control unit  320 . The single row  305  thus comprises the master controller  302  and several, horizontally-connected expansion base control units  318 ,  320 , so named because they receive commands sent to them from the master controller  302  and respond accordingly but are also able to act as “master” controllers to food holding units stacked above them. 
     The row  305  is depicted in  FIG. 3  as extending to the “right” of the master controller  302 . The number of units in a column and the number of units in rows is a design choice. The system can be extended vertically and horizontally with columns to the right of the master controller  302 . 
     The master controller  302  controls the food holding units  304 A,  306 A and  308 A that are arranged in the “first” peripheral communications bus vertical column  310 . The control of those vertically-stacked food holding units is accomplished by the master controller  302  assigning a unique address to each of unit  304 A,  306 A and  308 A such that bi-directional communications can take place between the master controller  302  and a slave food holding units  304 A,  306 A,  308 A using the first peripheral communication bus  312 , which is a multipoint multi-master communications bus. 
     Upon initial power on, the master controller  302  enters a power on discovery mode, in which the controller  302  detects and assigns addresses by sending a sequence of four messages exchanged between the master controller and a food holding unit located above the master controller. The first message sent to a food holding unit is a D.C. voltage applied to the interrogation signal wires that extend between adjacent food holding units. The D.C. voltage sent to a food holding unit on an interrogation signal wire  330  causes a food holding unit receiving the D.C. voltage to “wake up,” or monitor the communication bus  312 . After the D.C. voltage is applied to an interrogation signal wire, the food holding unit transmits a request for address message (“signal message”) on the first peripheral communications bus  312  to the master controller  302 . After the food holding unit transmits the address request message, the master controller transmits an address assignment message (“third message”) on the peripheral bus. When the address assignment message is received by the food holding unit to which the wake up signal was sent, the food holding unit stores an address contained within the address assignment message and sends an address confirmation message (“fourth message”) to the master controller  302 . Thereafter, the master controller and the food holding unit, in which the address was assigned, will communicate using this unique address throughout the rest of the time the unit is powered. 
     In a preferred embodiment the electrical interrogation signal transmitted or applied to the wire  330 - 1  is a D.C. voltage, typically less than twelve volts. The first peripheral communication bus  312  is a serial bus that uses the well-known CAN communications protocol, further description of which is omitted for brevity because the CAN standard is well known. 
     In addition to be coupled to the food holding units  304 A- 308 A that are vertically stacked above it, the master controller  302  is also coupled to other columns  314  and  316  of slave holding units  304 B- 308 B and  304 C- 308 C through horizontally-adjacent expansion bus controllers  318  and  320 , which are coupled to the master controller  302  through an electrically separate communications bus  322 , which is referred to as the second peripheral bus, and which are coupled to each other by D.C. voltage-carrying signaling wires  330 - 4  and  330 - 5 . The peripheral busses  324  and  326  are electrically isolated communication busses. 
     The horizontally-adjacent expansion base controllers  318  and  320  are so named because they act as master bus controllers for vertical column of food holding units that are stacked vertically above them. The expansion base controllers  318 ,  320  communicate with corresponding “columns” of slave food holding units  304 B- 308 B and  304 C- 308 C through corresponding communications buses  324  and  326  that extend from each expansion base controller to the columnar-oriented food holding units. In  FIG. 3 , communication bus  312  represents the first peripheral CAN bus whereas  324  and  326  represent the second and third peripheral CAN busses, respectively. 
     In some examples, the expansion base controllers have reduced functionality and structure than the master base controller, e.g., by employing smaller memory, lower end processors, and less computer-executable instructions. In some examples, however, one or more of the expansion base controllers may be a master controller or having the design and capability of a master controller, which may be beneficial for power management and routing in modular holding bins having an exceedingly large system communications buses. Furthermore, in some configurations it may be beneficial to have an expansion base controller provide redundancy capabilities in the event of a failure of the master base controller. Therefore, in some implementations one or more expansion base controllers may be duplicate master base controllers storing all or some portion of the instructions stored on the master base controller. 
     The ability to detect if a food holding unit is at a particular column/row location is provided by a method of detecting the presence of a food holding unit that obviates the need to pre-assign or provide fixed addresses to the food holding units but instead enables the food holding units to receive unique assignment identifications when they are installed into the network  300  and powered up. The assignment of an address to a food holding unit is performed by the master base controller such that the master base controller can become aware of the presence of any food holding unit that is plugged into any location along any of the CAN communication buses  312 ,  322 ,  324  and  326 . The CAN bus configuration, in particular, allows a system to more efficiently identify the holding unit configuration at initial power on and assign addresses dynamically, based on the holding unit configuration. 
     Thus, in the illustrated example, detecting and assigning a unique address to a food holding unit is accomplished by the network elements  302 - 308  asserting an interrogation signal, e.g., in the form of a DC voltage, on a wire that extends between adjacent network elements, where the receipt of the voltage at a second network element enables or permits a network element to transmit a response message on one of the communications buses  312 ,  322 ,  324  or  326 . 
     In the example of  FIG. 3 , the master controller  302  is configured to detect, upon power on, the presence or absence of a food holding unit by applying a voltage to the interrogation signal wire  330 - 1 , which extends from the master controller  302  to only the first vertical location  332  in the network  300  where a slave food holding unit might be installed. If a food holding unit  304 A is installed at that first location  332 , the food holding unit  304 A, having been given “permission” to transmit onto the bus by the voltage on the interrogation signal wire  330 - 1 , transmits a message onto the communications bus  312 . When the message from a food holding unit is detected by the master controller  302 , the controller  302  considers the response from the food holding unit to be indicative of the presence of a food holding unit at that first location  332 . The master controller  302  thereafter transmits a unique address assignment message on to the communications bus  312  which is received by the food holding unit  304 A at the first location  332  the receipt of which enables subsequent communications between the controller  302  and the food holding unit  304 A to take place via the first peripheral communications bus  312 . An address is assigned to food holding units so that subsequent communications with food holding units do not require the use of the interrogation signal wires  330 - 1 - 330 - n.    
     The presence of the additional food holding units in the first column  310  is achieved in progressive manner, with each holding unit sending an interrogation to the subsequent holding unit connected to it through an the interrogation signal wire. The second and third holding units are dynamically addressed, as a result. For example, the food holding unit  304 A at the first location  332  is configured to send a “wake up” signal on the interrogation signal wire  330 - 2 , in response to the holding unit  304 A receiving its address assignment from the master controller  302  via the peripheral bus  304 A. After receiving its address assignment, the holding unit  304 A assumes the role of a controller vis-à-vis the food holding unit  306 A installed at a corresponding second location  334 . This progressive interrogation process continues. If a second food holding unit  306 A is detected at the second location  334 , the second food holding unit  306 A at the second location  334  assumes the role of a controller vis-à-vis a food holding unit  308 A that might be installed at a corresponding third location  336 . 
     Thus, the second food holding unit  306 A is determined to be present or absent from a logically adjacent second location  334  in the column  310  by way of a DC voltage interrogation signal transmitted from the first holding unit  304 A at the first location  332  on the interrogation signal wire  330 - 2 , which extends between only the first and second locations  332 ,  334  in the first column  310 . The voltage interrogation signal may be applied automatically using instructions stored on the holding unit  304 A, e.g., instructions to automatically signal an interrogation signal in response to being assigned an address. In other examples, the holding unit  304 A sends the voltage interrogation signal in response to a particular command from the master controller  302 , and sent on the peripheral bus  312 . 
     After the “first message” is transmitted to the second location  334  by the first unit  304 A, the second food holding unit at location  344  sends a message onto the bus  312  to the master controller  302 . If the second unit  306 A is present, it will respond to the first message because the first type of message enables or authorizes the second unit  306 A to respond to the master base controller&#39;s over the CAN network. The second unit  306 A then sends its response to the first message over the peripheral CAN communications bus  312  to the master controller  302 . That response is a request for an address from the master controller  302  and as such is considered the second message in the four message communication exchange. 
     The master controller  302  will thereafter transmit a third message, which is the unique address assignment message to the second food holding unit  306 A at the second location  334  above the master controller  302 . The address assignment message, transmitted onto the bus  312 , contains a unique address that is used by the second food holding unit  306 A for subsequent communications. If no response is received by the master controller  302  from the second location  334 , the master controller  302  considers the second location  334  to be unoccupied. When the master controller  302  determines that the current location  334  has no food holding unit the vertical addressing for that column is now finished. 
     When the expansion base control unit  318  receives an address from the master controller  302 , the expansion base control unit  318  thereafter becomes a pseudo-master controller to the food holding units  304 B,  306 B, and  308 B vertically stacked above and communicatively coupled to the expansion base control unit  318  via interrogation signal wires  330 - 7 ,  330 - 9 ,  330 - 11  and a third communications bus  324  (second CAN peripheral bus) that extends between the expansion base control unit  318  and all of the vertically stacked food holding units in the second column  314 . 
     In order to detect whether expansion control units  318 ,  320  might be present in an adjacent vertical column  314 ,  316 , the master controller  302  first asserts or transmits a first type of message (i.e., an interrogation message) on interrogation signal wire  330 - 4  that extends from the master controller  302  to a laterally-adjacent expansion base control unit  318 , which is in turn able to communicate both vertically and horizontally as described above and hereinafter. Just as the master controller  302  does with holding units located in a first column above the master controller  302 , after the interrogation message is provided to the interrogation signal wire  330 - 4 , if an expansion base control unit  318  is in fact present at the first laterally adjacent location  340 , the expansion base control unit  318  at that location will respond to the interrogation message by transmitting an address request message to the master controller  302  on the system communications bus  322 . When the address request message from the expansion base control unit  318  is received by the master controller  302 , the master controller  302  transmits an address assignment message to the expansion base control unit  318 , again, on the system communications bus  322 . Upon the receipt of the address assignment message, the expansion base control unit  318  can thereafter act as a “master” controller to food holding units located above the expansion control unit  318  and which comprise the second column  314  of food holding units. The expansion control unit  318  can perform all or only a portion of the master controller operations, depending on system design. Furthermore, the expansion control units  318 ,  320 , etc. provide electrical and control isolation of their respective columns  314 ,  316 , etc. As such, if one or more holding unit goes down in a column, the column may be taken off line by the corresponding expansion control unit, without affecting the operation of the other columns and other expansion control units. With a CAN bus architecture, for example, the system bus  322  can be maintained across expansion control units, even if one of the expansion control units corresponds to a column taken off line. The expansion control unit can communicate a fault condition to the master controller, and the master controller correspondingly can communicate specific fault instructions to that expansion control unit, as well as stop sending instructions addressed to holding units on the corresponding column. 
     In the illustrated example, the detection of food holding units  304 B,  306 B,  308 B in the second column  314  and the assignment of addresses to them is performed by the master controller  302  using the process/method described above with respect to the master controller  302  and the food holding units  304 A,  306 A,  308 A in the first column  310 . The expansion control units  318 ,  320  do not assign addresses nor do they detect food holding units above them. Rather these expansion control units facilitate address assignment to by the master controller  302 . That is, the illustrated example, addresses are assigned to food holding units  304 B,  306 B and  308 B by the master controller  302  by way of messages it transmits over the systems communications bus  322  to the slave control unit  318 , which passes the messages onto the second peripheral communications bus  324 . 
     The detection of food holding units in a third column  316  of food holding units  304 C,  306 C and  308 C and the assignment of unique addresses to them is performed in the same way that food holding units  304 B,  306 B and  308 B are detected in the second column  314  and addresses are assigned to them. The description of the process for the third column  316  is therefore omitted in the interest of brevity. In addition columns  4 -N will be discovered, addressed and communicating in the same method as described above. The number of columns is a design choice and is not limited by this method. 
       FIG. 4  is a block diagram of a master controller  302  depicted in  FIG. 3 . A signal-chip microcontroller  402  having non-transitory memory devices  403  co-located on the same semiconductor die  404  executes program instructions that are stored in the “on-chip” memory  403 . Those instructions cause the processor  402  to perform various operations to detect the presence of logically-adjacent food holding units and communicate with them via one or more communications busses. 
     The processor  402  is also electrically coupled to a memory device, typically an EEPROM  406  through a conventional address/data/control bus  408 . System configuration data, e.g., menus and settings, are stored in the memory device  406 . 
     The processor  402  is coupled to two CAN-based transceivers  410  and  412 , which are coupled to the processor  402  through corresponding ports  414  and  416 . The first CAN transceiver  410  is coupled to a column-adjacent slave module  418 , i.e., a slave module in the same column  310 , through a CAN compliant communications bus  420  and an interrogation signal wire  421 . 
     The second CAN transceiver  412  is coupled to a slave control unit  422 , also referred to as an expansion base  422  through an interrogation signal wire  426  on which a voltage can be applied and a CAN-compliant bus  424 . 
     The master controller  302  further includes a power recovery module  430 , discussed further below in reference to  FIG. 8 . 
       FIG. 5  is a block diagram of a food holding unit  500 . Such a food holding unit would be located and operating in one of the locations  304 - 308  in  FIG. 3 . It is comprised of a microcontroller  502  coupled to either the master controller  302  or a “previous module” in the network  300  by way of a communications bus  504  and an interrogation signal line  506  on which the aforementioned “first type of message” (or interrogation message) is transmitted to the processor  502  for the food holding unit  500 . 
     Reference numeral  506 A represents an incoming interrogation signal wire or line that is connected to an input terminal of the microcontroller  502 .  506 B represents an outgoing interrogation signal wire or line by which the food holding unit  500  can assert the incoming interrogation signal wire of the “next module.”  518  identifies a CAN transceiver, which allows the microcontroller  502  to communicate on the bus  504 . 
     Each food holding unit  500  in a modular holding bin is provided with a capacitive type touchscreen display board  510 . Upper and lower heating elements  512 ,  514  are controlled by the microcontroller  502  to maintain a required temperature that is assigned food to the unit  500  by the master controller  302 . 
     Temperature sensors  516 A and  516 B, preferably embodied as a K-type thermocouple, which is mechanically coupled to the heating elements, the current of which is temperature-dependent, enable the processor  502  to monitor the temperature in the food holding unit  500  and apply or reduce current to the upper heaters  512  and lower heater  514  respectively. 
       FIG. 6  is a block diagram of an expansion control unit (or slave control unit)  600 , which when installed in the network shown in  FIG. 3  enables the master controller  302  to communicate with slave food holding units in different columns  314  and  316 . The expansion controller  600  comprises a processor  602  coupled to a CAN transceiver  604 , which couples the processor  602  to a conventional address/data/control bus  606 . The transceiver  604  is coupled to the systems communications bus  322 . A second CAN transceiver  608  enables the processor  602  to communicate with slave food holding units located “above” the expansion controller  600  in a column. 
     In  FIG. 6 , reference numeral  612  identifies an incoming signal wire on which the aforementioned first type of message is sent to the slave control unit  600 . Reference numeral  614  identifies an outgoing signal wire on which the slave control unit  600  can send the “first type of message” to a first vertical unit in a column that extends upwardly from the slave control unit  600 . Reference numeral  616  is an outgoing signal wire on which the slave control unit  600  can send the “first type of message” to a horizontally-adjacent next slave control unit. 
       FIG. 7  is a flowchart depicting a method  700  for providing a modular food holding cabinet, such as the one shown in  FIGS. 1 and 2  and which employ a network such as the one depicted in  FIG. 3  that is able to detect and control food holding units connected to each other in different configuration. 
     A first block  702 , a “first type of message” is transmitted on a single conductor or wire that extends between a controller and a location where a device might be installed. In a preferred embodiment such a message is simply a DC voltage applied to the wire. In an alternate embodiment, however, such a signal could just as well be an AC voltage, the magnitude and frequency of which can be selected as a design choice. Serial data could also be transmitted. As stated above, the first type of message gives a receiving food holding unit “permission” to transmit onto a communications bus. 
     After the “first type” of messages transmitted on the wire connecting the controller to a slave unit location At the next block  704 , if a slave unit is present, a request for address message is transmitted from the slave controller to master controller. If a slave unit was present when the voltage on the first wire was asserted and detected, the slave unit sends the address request message to the master base controller. At block  706 , the master base unit will determine if the message sent via block  704  was received by the master controller  302 . The process  700  continues to look for the address request message until a timeout occurs as determined by the block  707 , at which point the process  700  determines that no additional holding unit is present, via block  709 , and the process ends. 
     Upon the main base controller&#39;s receipt of the address request message, sent via block  704 , the master controller transmits a unique address to the slave unit requesting the address at block  708 . If the message is received at the slave holding unit, block  710 , then the slave holding unit stores the assigned address and sends an address confirmation message to the master controller via block  712 . Thereafter, the slave unit and the controller will communicate with each other using this address, for example, in header data communicated on the peripheral and system busses. After assignment of the addresses, the process  700  may stop or control may be passed to block  702  to search for further slave controllers, in accordance with the techniques described herein. The process  700  further includes a timeout, via block  714 , that ends the process if the slave holding unit never receives the address assignment from the master controller, in which case control is passed to block  709 , and the process ends. 
     In examples herein, interrogation signal wires may be electrically isolated from one another and from the CAN peripheral and CAN system busses. 
     The various communications buses are also electrically isolated from one another, namely the peripheral and system busses. This isolation provides considerable advantage as modular holding bin systems increase in size to including numerous columns of holding units. The modular holding bin architecture is able to extend the system bus to include the addition of new expansion control units but while still maintaining isolation of the peripheral bus for each expansion control unit. As a result, any column of holding units can be taken offline, including the column assigned to the master base controller, and the other columns may be maintained under normal operation. 
     Those of ordinary skill in the computer network art know that a media access control address (MAC address) is a unique identifier that is assigned to each network interface for communications on a physical network. MAC addresses are used as a network address for most IEEE 802 network technologies as well as Ethernet networks. They enable each device on a network to be communicated with individually. 
     The method and apparatus described above enable food holding units in a modular food holding bin (e.g., cabinet) to be uniquely addressable and controllable over a bus, without requiring the food holding unit to be manufactured or constructed with a unique hardware address, similar to a MAC address. The food holding units are instead manufactured without an address pre-assigned to them. A food holding unit is instead assigned a unique address, functionally equivalent to a MAC address, each time it is installed into the modular holding cabinet and powered on. A food holding unit can thereafter be re-assigned new addresses, each time the power is cycled on in the holding bin system. The food holding units can thus be reconfigured as needed and re-used in different configurations. 
     In some examples, a modular holding bin will have a master controller that includes a power recovery mode that allows the modular holding bin to recover operations in the event of a loss of power, thereby maximizing a customer&#39;s chances of retaining food and product within the heating device without prematurely disposing of such food or product in response to a power failure.  FIG. 8  illustrates an example power recovery module  800  that may be implemented as the power recovery module  430  of the master controller  302 . 
     Generally speaking, modular holding bins are commonly used in food environments, such as restaurants and fast food restaurants in particular, to keep precooked food safe and edible from the time when it is cooked until it is provided to the customer. The main parameters that holding modules (units) observe are time and temperature. However, other parameters such as humidity can be considered. Because holding modules are electronically controlled devices, if the power is lost during a hold cycle, without appropriate tracking of the conditions, it can be difficult to impossible determine if the food in the holding modules is still good when the power is restored. Due to the safety and quality concerns, often food is discarded regardless of its true condition. This problem is exacerbated in countries and communities where power is often lost 5-50 times daily, due to lacking power infrastructure. 
     The power recovery module  800  is able to manage recovery of a modular holding device after a power loss, whether that loss is unintentional or due to an intended powering off of the modular holding device. Moreover, the power recovery module  800  is able to provide power recovery in response to power loss to an entire modular holding device, such as the modular holding bin  100 , or in response to power loss to any of the units ( 304 - 308 ) contained within the modular holding unit ( 100 ). 
     In the example of  FIG. 8 , the power recovery module  800  includes recipe module  802  a timing module  804 , a temperature module  806 , and recovery control module  808 . 
     The recipe module  802  stores food processing instruction data, also termed herein recipe data. This recipe data may include the operating set points for the upper and lower heaters (such as  512  and  514 , respectively) of a holding module. These temperature set points partly define the normal operating conditions for each of the holding modules, where different modules are programmed to different temperature set points based on the type of food to be heated in the respective module. The recipe data further includes a food or product identifier type (such as meat, poultry, fish, egg, bread, liquid, etc.). 
     The recipe data further includes a timing data, such as the current time remaining on a recipe being active in a holding module. This timing data may be dynamically updated through communications on the CAN peripheral and CAN system busses. For example, an initial recipe may include temperature set points of 150° F. and 160° F. for the upper and lower heater elements, respectively, and a food identifier of “meat” and a total heating time, or total cooking time, of 7 minutes. The module  802  stores that recipe data for a particular holding module. Once an operator activates that holding module, i.e., places meat in the module and presses a start button, the holding module sends a start cooking (or start recipe) signal to the master controller, where that signal is transmitted over the CAN peripheral bus and indicates that a holding unit event has started. For example, at the time that the start button is pressed to start the timer on any holding module  304 - 308 , a start cooking signal is sent to the master controller  302 , which then writes a reference clock value to one of the attributes of that specific holding module that is stored in the timing module  804  of the master controller. This process of recording a reference clock is done for any holding module in the modular holding bin at any time a timer has been started on the holding module user interface. 
     The reference clock stored at the timing module  804  can be generated a number of different ways. In some examples, the master controllers include electronics that keep a battery-backed running clock or timer that is continually running since the master controller has been functioning. In some examples, that means the master controller has a running clock/timer since factory completion. That clock/timer may be powered by an alternate power source, such as an internal battery in the master controller, that is separate from the power supply providing powered operation of the modular holding bin. This reference clock/timer keeps a running time that is used to timestamp data received from holding modules as they execute their recipes. In these examples, the reference clock/timer indicates a lifetime of the modular holding bin (or master controller thereof). The stored reference clock data may contain seconds data, minute data, etc. or the reference clock data may contain a numerical number indicative of seconds data, minute data, etc. The recovery control module  80  and timing module  804  may reference this timing data at any time the modular holding bin is powered on, although the clock/timer will be running even with a power is off, due to its alternative power source. 
     During operation of the holding modules (e.g., holding units  304 - 308 ), the remaining time for each executing recipe is periodically communicated from the holding module to the master controller, which stores this remaining time value in the timing module  804 . The holding modules may be configured to transmit their remaining time each minute on the CAN peripheral bus to the master controller, for example. The timing module  804  may store that remaining time value as an attribute field of the stored recipe data for each active holding module. Further the timing module  804 , upon receiving that remaining time value may store that timing data with a time stamp from the reference clock/timer, providing a global time to when the remaining time data was stored. The process repeats until the timer expires for the respective holding module. 
     Thus as shown, in some examples, the timing module  804  stores the total hold time for a recipe to be executed by a given holding module. The timing module  804  stores a reference (or global) relative timer value that is based on a clock external to the recipe executing (or to be executed) by a holding module. The timing module  804  further stores a log of system timer values, i.e., the received timing data, for each holding module reporting to the master controller during execution of a recipe. Further still, the timing module  804  includes data identifying all running timers (and corresponding holding modules) in the modular holding bin. 
     The timing module  804  and the temperature module  806  are used, along with the recovery control module  808 , in a power recovery mode of the modular holding bin as shown in  FIG. 9 . 
     When power is lost to the modular holding bin or any particular holding module that is condition is called a “power fault condition.” Typically, power is lost to the entire modular holding bin, therefore we describe example operations for that situation. Other power fault conditions, however, are contemplated and resolvable by the present techniques as well. 
     When a power fault condition occurs and power is lost to the modular holding bin, e.g., bin  100 , all active timers in the holding modules will cease to operate. All heaters will cease to operate as well, and the temperature in the holding module will begin to drop. Upon power restart, when power is restored, the time module  804  determines an amount of time since the power was lost, i.e., the amount of time since the power fault condition occurred. The total time of the power fault condition, from start until the time power is sufficiently restored, is called the “power fault window.” 
     During the power fault window, in the illustrated example of  FIG. 8 , the reference clock/timer, with auxiliary power source, is still maintained in operation. That is, the master controller is still recording its reference clock/timer. When power is restored, the master controller enters a new discovery mode, as discussed hereinabove, where the master controller ( 302 ) discovers the presence of the holding units ( 304 - 308 ) and any expansion controllers ( 318  and  320 ). The locations of the holding hunts identified and their data tables are filled. From here, the power recovery  800  is activated and captures the current reference time/clock from the reference clock/timer. For example, the time module  804  may access the reference time/clock for its current value. The timing module  804  then determines if there are any active timers, which can be done by checking for any timer data in the timing module  804  showing timers that still have time remaining, upon power restart. If there are any active timers, that means that the timers, and corresponding holding modules, running at the time of the power fault condition. In the power recovery process  900  in  FIG. 9 , this determination is shown at block  902 . The block  902  is described as performed by the timing module  804 , but in other examples, the determination is made by the recovery control module  808  or other module in the power recovery module  800  or elsewhere in the master controller. 
     While the examples of  FIGS. 8 and 9  are described in reference to a reference clock/timer operating on the master controller, in other examples, the reference clock/timer can be a global clock value obtained from an external time source coupled to the module  800  through an optional communication interface module  810 . For example, a time module may be configured to obtain the current global time from an external computer server coupled through a wired or wireless network coupled to the communication interface module  810 . In such examples, that external clock may be used during normal powered on operation of the modular holding bin, continuously or periodically receiving a global clock value from the external source and using that global clock value for time stamp purposes. 
     In  FIG. 9 , if the timing module  804  determines that there were no active timers at the time of power restart, then no timer recovery operation is employed, and control is passed to a block  904 , in which the recovery control module  808  gathers all last known used recipes stored in the recipe module  802  and all the holding module location data stored in the master controller. From this information, the recovery control module  808  instructs the master controller to send all recipe data, e.g., as recipe images to the holding modules. The recovery control module  808  instructs the master controller to send all recipe timer data (also termed hold time data) to the respective holding modules, along with the upper and lower setpoint temperature data. The process  900  then ends. 
     If the timing module  804  determines there are active times, then control is passed to a block  906 , in which current timing and temperature date is captured and stored. The block  906  determines which holding modules have active timers, which are the holding modules that need recovery. For example, the timing module  904 , which has previously stored time remaining data, obtains the last logged time remaining data (with time stamp) for all active holding modules. The timing module  904  obtains the reference clock/timer data and determines the elapsed time since the power fault condition, by subtracting from the current reference clock/timer value, which in this example is a system time, the last logged timed value, namely the time stamp of the last logged time remaining data. This time may also be called the last time due to power outage. 
     From this data, the timing module  804  then determines for each holding module, the recalculated time remaining for the respective recipes. This time remaining value may be determined by subtracting the time of the power fault window, i.e., the lost time due to power outage, from the last logged timing remaining value. 
     The time comparison identifies which holding modules have active timers, and this data is identified to the recovery control module  808 , which then instructs the temperature module  806  to obtain current temperature data from the identified holding modules. 
     For example, the time module  806  requests current temperature heating data for the upper and lower heater elements in each of the active timer holding modules by instructing the master controller to send a request signal on the CAN peripheral busses to each of the active time holding modules. The active timer holding modules respond by sending temperature data from temperature sensors  516 A and  516 B to the master controller which sends it to the temperature module  806 . 
     In other examples, the temperature module may be configured to determine the current holding temperature algorithmically, by receiving time lost data from the time module  804 . The temperature module may then determine, for example using stored thermal coefficient data for various food products types, sizes, etc., the expected current temperature of the stored food based on a projected (or stored) temperature at the time of the power fault condition and the amount of time since the power fault condition. 
     At a block  908 , the recovery control module  808  determines a disposition of the active timer holding modules based on the determined timing data and current temperature data. That is, the recovery control module  808  can determine the impact of the power fault on operation of each holding module in the modular holding bin. The recovery module  808  determines whether the conditions of the power fault condition and power fault window are such that the product/food in each of the holding modules affected by the power fault condition (i) can be retained or (ii) should be discarded. 
     In an example, at the block  908 , the module determines if any of the active timers have expired, that is, if the lost time of the power fault window is greater than the most recently logged time remaining value stored before the power fault condition. If any of the timers are expired, then the recovery module  808  flags the corresponding holding modules, or more specifically, flags a stored data field therein for each of the expired holding modules. 
     For any holding modules that have non-expired active timers, at block  910  the recovery control module  808  restores all recipe images and or names, by instructing the master controller to send recipe data to these active timer holding modules. That includes, sending the total recipe time, i.e., the total hold time, the upper and lower temperature setpoint temperatures and determining and sending updated time remaining data to all expired active timers. Note, at the block  910 , the module  808  may also restore the recipes for all non active holding modules that were identified at block  902  as not having any active time at the time of the power fault condition. 
     At a block  912 , the recovery module  808  identifies which holding modules were flagged as having an expired timer. At a block  914 , the recovery module  808  generates a fault instruction for each such module and instructs the master controller to send that fault instruction to each such module. The receiving holding module displays a fault indication on the display of the module, identifying the operate that the contents in the holding module should be disposed. In some examples, the holding module will display a fault indication and await a user input, such as a pressing the push button display itself, acknowledging the push button. After acknowledgement is received and communicated back to the master controller on the CAN peripheral bus, the recovery module  808  clears the active timer flag. 
     For holding modules that were not flagged has having non-expired active timers, at a block  916 , the recovery module  808  instructs the master controller to transmit the updated active time remaining data to the holding modules, for example, sending that update on the CAN peripheral. The holding modules will display the updated time remaining, recalculated by the timing module  804  to compensate for the time lost during the power fault window. The holding modules display the updated time remaining data as timer data on their displays, indicating the user how much time is left before the recipes is completed. 
     In some examples, the recovery control module  808  determines which holding modules have expired active timers, not only from the timer data determined upon power recovery and the current temperature values, but also based on a tunable parameter that may be stored in the recipe module  802 . That tunable parameter represents an expiration time for a specific recipe to be applied when the power is lost. The tunable parameter may be stored for each recipe in the recipe module  802  and the tunable parameter may be adjusted by a programmer. In this example, if the time lost is greater than the tunable recipe expiration value, then the recovery control module  808  determines that the active timer for the holding module is to be stopped and the food/product is to be discovered according to block  914 . If the total time loss is less than the tunable expiration value, then recipe is loaded into the holding machine by the master controller, at block  916  and a timer active indicator is sent to the holding module. 
       FIG. 10  illustrates an example network  1000  for use in programming operation of remote modular holding bins, such as those described hereinabove. The network  1000  can be any suitable local or wide area network(s) including a Wi-Fi network, a Bluetooth network, a cellular network such as 3G, 4G, Long-Term Evolution (LTE), the Internet, etc. The network  1000  may be a wireless network or a wired network. The network  1000  communicates with a plurality of modular holding bins  1002 A- 1002 C, three of which are shown for example purposes, but which would include more modular holding bins in a typical networked environment. Each modular holding bin  1002 A- 1002 C may hold an array of holding units (holding modules), as discussed, for example, in reference to  FIGS. 1-3  above. Further each modular holding bin  1002 A- 1002 C may be located in remote locations from each other, such as at different food service stores for a given user, or customer. The modular holding bins  1002 A- 1002 C each include a network interface controller  1004 A- 1004 C providing communications with the network  1000 . 
     User stations  1006 A and  1006 B are coupled to the network  1000  through respective network interface controllers  1008 A and  1008 B. A central station  1010  is also coupled to the network  1000  through a network interface controller  1012 . The central station  1010 , which includes one or more processors and one or more computer-readable mediums, stores programming instructions that the station  1010  sends to the modular holding bins  1002 A- 1002 C over the network  1000 . Those programming instructions can include, for example, instructions for executing a discovery mode using a master base controller, as described herein, recipe instructions to be stored and executed by the holding modules within the modular holding bins, instructions for a power recovery mode using a master base controller, as also described herein, and other instructions. 
     The central station  1010  also provides communication with the user stations  1006 A and  1006 B through the network  1000 . In some examples, that communication provides recipe instructions and other instructions that are executed on the user stations  1006 A and  1006 B to allow an operator at the user station to adjust the instructions, also termed “tuning” the instructions, before the instructions are sent to the modular holding bins  1002 A- 1002 B for execution. 
       FIG. 11  illustrates an example user station  1100  as may be implemented as the user stations  1006 A and  1006 B in  FIG. 10 . The user stations  1100  includes one or more processors (CPU)  1102 , one or more memories  1104 , and an input/output (I/O) module  1106 . The one or more memories  1104  may include a tangible, non-transitory memory and may include any types of suitable memory modules, including random access memory (RAM), read only memory (ROM), flash memory, other types of persistent memory, etc. The memory  1104  stores an operating system (OS) and one or more modules. The operating system may be any type of suitable operating system. The I/O module  1106  may be a keyboard or a touchscreen, for example. 
     For illustration purposes, the user station  1100  is depicted including a user interface module, which may be stored in the memory  1104  or stored separately, and which represents a user interface layer that presents a graphical user interface to an operator, allowing that operator to individually adjust, or “tune,” different payload components  1110 ,  1112 , and  1114  in a tunable payload layer  1116 . The tuned payload components  1110 ,  1112 , and  1114  are provided to a modular holding bin instruction layer  1118  that can include recipe instructions, discovery mode instructions, power recovery mode instructions, and other instructions received from the central station  1010 . The tuned payload components may be published into the modular holding bin instruction layer  1118  by the operator after the operator has adjusted respective aspects of one or more of those components. The result is a tuned modular holding bin instruction data set that is then communicated to whichever of the modular holding bins  1002 A- 1002 C correspond to the particular user station  1100 , e.g., through a network communication interface layer  1120 . In this way, any user station coupled to the network  1000  is able to remotely program instructions into their corresponding modular holding bins. Moreover, any user station can program multiple modular holding bin by broadcasting tuned instructions to all their modular holding bins connected to the network  1000  in a simultaneously broadcasted manner, thereby greatly reducing recipe updates and modular holding bin downtime. 
     The tunable payload components  1110 ,  1112 , and  1114  may represent N number of tunable components, where N is equal to or greater than 1. Each component  1110 ,  1112 , and  1114  may represent one or more variables used in the programming instructions of a modular holding bin. Each payload component  1110 ,  1112 , and  1114  may represent a category of tunable instructions, such as shown in  FIGS. 12-14 . 
       FIG. 12  is a graphic user interface showing tunable “General Parameters”  1200  that form a first tunable payload component (such as payload component  1110 ). The General Parameters  1200  include tunable Temperature Regulation parameters  1202 , tunable System Parameters  1204  and a tunable Cleaning Mode Parameter  1206 . For each of the illustrated parameters, the user is provided with a tuning button for increasing or decreasing the associated tunable value. 
       FIG. 13  is a graphic user interface showing tunable “Diagnostics Test Bypass Parameters”  1300  that form a second tunable payload component (such as payload component  1112 ). The Diagnostics Test Bypass Parameters  1300  include tunable parameters for instructing a modular holding bin to bypass different aspects of a diagnostic test performed, e.g., during initial power startup of the modular holding bin. For each of the illustrated parameters, the user is provided with a tuning button for increasing or decreasing the associated tunable value. 
       FIG. 14  is a graphic user interface showing tunable “Diagnostics Test Parameters”  1400  that form a third tunable payload component (such as payload component  1114 ). The Diagnostics Test Parameters  1300  include tunable parameters for use by a modular holding bin in performing a diagnostic test, e.g., during initial power startup of the modular holding bin. For each of the illustrated parameters, the user is provided with a tuning button for increasing or decreasing the associated tunable value. 
     Throughout this specification, plural instances may implement components, operations, or structures described as a single instance. Although individual operations of one or more methods are illustrated and described as separate operations, one or more of the individual operations may be performed concurrently, and nothing requires that the operations be performed in the order illustrated. Structures and functionality presented as separate components in example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein. 
     Additionally, certain embodiments are described herein as including logic or a number of routines, subroutines, applications, or instructions. These may constitute either software (e.g., code embodied on a machine-readable medium or in a transmission signal) or hardware. In hardware, the routines, etc., are tangible units capable of performing certain operations and may be configured or arranged in a certain manner. In example embodiments, one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware modules of a computer system (e.g., a processor or a group of processors) may be configured by software (e.g., an application or application portion) as a hardware module that operates to perform certain operations as described herein. 
     In various embodiments, a hardware module may be implemented mechanically or electronically. For example, a hardware module may comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) to perform certain operations. A hardware module may also comprise programmable logic or circuitry (e.g., as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. It will be appreciated that the decision to implement a hardware module mechanically, in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations. 
     Accordingly, the term “hardware module” should be understood to encompass a tangible entity, be that an entity that is physically constructed, permanently configured (e.g., hardwired), or temporarily configured (e.g., programmed) to operate in a certain manner or to perform certain operations described herein. Considering embodiments in which hardware modules are temporarily configured (e.g., programmed), each of the hardware modules need not be configured or instantiated at any one instance in time. For example, where the hardware modules comprise a general-purpose processor configured using software, the general-purpose processor may be configured as respective different hardware modules at different times. Software may accordingly configure a processor, for example, to constitute a particular hardware module at one instance of time and to constitute a different hardware module at a different instance of time. 
     Hardware modules can provide information to, and receive information from, other hardware modules. Accordingly, the described hardware modules may be regarded as being communicatively coupled. Where multiple of such hardware modules exist contemporaneously, communications may be achieved through signal transmission (e.g., over appropriate circuits and buses) that connects the hardware modules. In embodiments in which multiple hardware modules are configured or instantiated at different times, communications between such hardware modules may be achieved, for example, through the storage and retrieval of information in memory structures to which the multiple hardware modules have access. For example, one hardware module may perform an operation and store the output of that operation in a memory device to which it is communicatively coupled. A further hardware module may then, at a later time, access the memory device to retrieve and process the stored output. Hardware modules may also initiate communications with input or output devices, and can operate on a resource (e.g., a collection of information). 
     The various operations of the example methods described herein may be performed, at least partially, by one or more processors that are temporarily configured (e.g., by software) or that are permanently configured to perform the relevant operations. Whether temporarily or permanently configured, such processors may constitute processor-implemented modules that operate to perform one or more operations or functions. The modules referred to herein may, in some example embodiments, comprise processor-implemented modules. 
     Similarly, the methods or routines described herein may be at least partially processor-implemented. For example, at least some of the operations of a method may be performed by one or more processors or by processor-implemented hardware modules. The performance of certain of the operations may be distributed among the one or more processors, not only residing within a single machine, but also deployed across a number of machines. In some example embodiments, the processor or processors may be located in a single location (e.g., within a hospital, within a home environment, an office environment or as a server farm), while in other embodiments the processors may be distributed across a number of locations. 
     The performance of certain of the operations may be distributed among the one or more processors, not only residing within a single machine, but also deployed across a number of machines. In some example embodiments, the one or more processors or processor-implemented modules may be located in a single geographic location (e.g., within a hospital, within a home environment, an office environment, or a server farm). In other example embodiments, the one or more processors or processor-implemented modules may be distributed across a number of geographic locations. 
     Unless specifically stated otherwise, discussions herein using words such as “processing,” “computing,” “calculating,” “determining,” “presenting,” “displaying,” or the like may refer to actions or processes of a machine (e.g., a computer) that manipulates or transforms data represented as physical (e.g., electronic, magnetic, or optical) quantities within one or more memories (e.g., volatile memory, non-volatile memory, or a combination thereof), registers, or other machine components that receive, store, transmit, or display information. 
     As used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     Some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. For example, some embodiments may be described using the term “coupled” to indicate that two or more elements are in direct physical or electrical contact. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments are not limited in this context. 
     As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive “or” and not to an exclusive “or.” For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). 
     In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the description. This description, and the claims that follow, should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. 
     This detailed description is to be construed as an example only and does not describe every possible embodiment, as describing every possible embodiment would be impractical, if not impossible. One could implement numerous alternate embodiments, using either current technology or technology developed after the filing date of this application. 
     The foregoing description is for purposes of illustration only. The true scope of the invention is set forth in the following claims.