Abstract:
In one aspect, a dishwasher comprising a controller coupled to a human machine interface comprising an indicator corresponding to a dishwasher model type is described. The dishwasher further comprises a cabinet comprising a tub having a front opening and forming a wash chamber, at least one rack extending into the wash chamber, a water pump for pumping water into the dishwasher, and a door engaged to the cabinet for closing the tub front opening. The controller is configured to control operation of at least the pump based on the model type indicator.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to dishwashers, and, more particularly, to methods and systems determining dishwasher model.  
           [0002]    Known dishwasher systems include a main pump assembly and a drain pump assembly for circulating and draining wash fluid within a wash chamber located in a cabinet housing. The main pump assembly feeds washing fluid to various spray arm assemblies for generating washing sprays or jets on dishwasher items loaded into one or more dishwasher racks disposed in the wash chamber.  
           [0003]    Many different model dishwashers are commercially available, and each dishwasher model may have different structural features, operational features, and controls from other dishwasher models. For example, the number of spray arms, the types of spray, and wash cycles can vary from model to model. Different control schemes typically are used in each different dishwasher model. For example, a control scheme for two level spray dishwasher model is different from a control scheme for a three level spray dishwasher model.  
           [0004]    Although different control schemes are used for different dishwasher models, dishwasher manufacturers typically utilize a common control board typically for most if not all dishwasher models. A typical control board includes a microprocessor coupled to a memory. The microprocessor operates under control of a program and variables stored in the memory. The program executed and the variables utilized can vary from model to model. For example, cycle times and wash instructions can vary from model to model. Utilizing a common control board across different dishwasher models facilitates inventory and cost reductions.  
           [0005]    In order for the microprocessor to execute the correct programs utilizing the correct variables for a particular dishwasher model, a model selection input is provided to the microprocessor. However, since the control board can be utilized in many different dishwasher models, the particular dishwasher model in which a control board is installed may not be known until a late point in the manufacturing process. Therefore, at the time of loading the programs and variables into the control board memory, it is not known in which particular model dishwasher the control board will be installed.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    In one aspect, a dishwasher comprising a controller coupled to a human machine interface comprising an indicator corresponding to a dishwasher model type is described. The dishwasher further comprises a cabinet comprising a tub having a front opening and forming a wash chamber, at least one rack extending into the wash chamber, a water pump for pumping water into the dishwasher, and a door engaged to the cabinet for closing the tub front opening. The controller is configured to control operation of at least the pump based on the model type indicator.  
           [0007]    In another aspect, a method for controlling operation of a dishwasher is described. The dishwasher comprises a controller and a human machine interface, and the human machine interface comprises an indicator corresponding to a model type. The method comprises the steps of determining a model type based on the indicator, and controlling operation of the controller in accordance with the determined model type.  
           [0008]    In yet another aspect, a kit comprising a human machine interface for a dishwasher is described. The human machine interface comprises an indicator corresponding to a dishwasher model type. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 a side elevational view of an example dishwasher system partially broken away;  
         [0010]    [0010]FIG. 2 is a block diagram of a dishwasher control board and human machine interface (HMI);  
         [0011]    [0011]FIG. 3 is a more detailed block diagram of components of the dishwasher control board and HMI shown in FIG. 2; and  
         [0012]    [0012]FIG. 4 is a circuit diagram of an analog interface circuit.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]    [0013]FIG. 1 is a side elevational view of an exemplary domestic dishwasher system  100  partially broken away, and in which the present invention may be practiced. It is contemplated, however, that the invention may be practiced in other types of dishwashers and dishwasher systems other than just dishwasher system  100  described and illustrated herein. Accordingly, the following description is for illustrative purposes only, and the invention is not limited to use in a particular type of dishwasher system, such as dishwasher system  100 .  
         [0014]    Dishwasher  100  includes a cabinet  102  having a tub  104  therein and forming a wash chamber  106 . Tub  104  includes a front opening (not shown in FIG. 1) and a door  120  hinged at its bottom  122  for movement between a normally closed vertical position (shown in FIG. 1) wherein wash chamber is sealed shut for washing operation, and a horizontal open position (not shown) for loading and unloading of dishwasher contents.  
         [0015]    Upper and lower guide rails  124 ,  126  are mounted on tub side walls  128  and accommodate upper and lower roller-equipped racks  130 ,  132 , respectively. Each of upper and lower racks  130 ,  132  is fabricated from known materials into lattice structures including a plurality of elongate members  134 , and each rack  130 ,  132  is adapted for movement between an extended loading position (not shown) in which at least a portion of the rack is positioned outside wash chamber  106 , and a retracted position (shown in FIG. 1) in which the rack is located inside wash chamber  106 . Conventionally, a silverware basket (not shown) is removably attached to lower rack  132  for placement of silverware, utensils, and the like that are too small to be accommodated by upper and lower racks  130 ,  132 .  
         [0016]    A control input selector  136  is mounted at a convenient location on an outer face  138  of door  120  and is coupled to known control circuitry (not shown) and control mechanisms such as a control board (not shown) for operating a fluid circulation assembly (not shown in FIG. 1) for circulating water and dishwasher fluid in dishwasher tub  104 . Selector  136  sometimes is referred to herein as a Human Machine Interface (HMI)  136 . Typically, a different HMI  136  is utilized for different dishwasher models since the inputs required from a user vary from model to model.  
         [0017]    The fluid circulation assembly is located in a machinery compartment  140  located below a bottom sump portion  142  of tub  104 , and its construction and operation is explained in detail below. A lower spray-arm-assembly  144  is rotatably mounted within a lower region  146  of wash chamber  106  and above tub sump portion  142  so as to rotate in relatively close proximity to lower rack  132 . A mid-level spray-arm assembly  148  is located in an upper region of wash chamber  106  in close proximity to upper rack  130  and at a sufficient height above lower rack  132  to accommodate items such as a dish or platter (not shown) that is expected to be placed in lower rack  132 . In a further embodiment, an upper spray arm assembly (not shown) is located above upper rack  130  at a sufficient height to accommodate a tallest item expected to be placed in upper rack  130 , such as a glass (not shown) of a selected height.  
         [0018]    Lower and mid-level spray-arm assemblies  144 ,  148  and the upper spray arm assembly are fed by the fluid circulation assembly, and each spray-arm assembly includes an arrangement of discharge ports or orifices for directing washing liquid onto dishes located in upper and lower racks  130 ,  132 , respectively. The arrangement of the discharge ports in at least lower spray-arm assembly  144  results in a rotational force as washing fluid flows through the discharge ports. The resultant rotation of lower spray-arm assembly  144  provides coverage of dishes and other dishwasher contents with a washing spray. In various alternative embodiments, mid-level spray arm  148  and/or the upper spray arm are also rotatably mounted and configured to generate a swirling spray pattern above and below upper rack  130  when the fluid circulation assembly is activated.  
         [0019]    [0019]FIG. 2 is a block diagram of a controller  150 , sometimes referred to herein as a dishwasher control board, and human machine interface (HMI)  136  for dishwasher  100 . Although a common control board  150  typically is utilized across various dishwasher models, HMI  136  typically is different for each model. Specifically, since the functions and features vary from model to model, the inputs required from the user also vary from model to model.  
         [0020]    Since HMI  136  varies from model to model, HMI  136  can be designated to carry an indicator or identifier used by control board  150  with respect to the model dishwasher in which control board  150  is installed. The indicator can take many different forms, and the indicator is not limited to the specific embodiment described herein. For example, rather than a resistor (R model ) that corresponds to a particular dishwasher model, the indicator can comprise a more complex circuit. In addition, and rather than an electrical circuit component, a mechanical feature could be added to HMI  136  that interfaces with control board  150  to designate a particular model. For example, a flexible connector can extend from HMI  136  to control board  150 , and the connector can have a unique pin assignment that corresponds to a particular model dishwasher.  
         [0021]    [0021]FIG. 3 is a more detailed block diagram of example components of controller  150  and HMI  136 . Controller  150  includes a processor  152 , such as a microprocessor coupled to a memory  154  and an analog interface circuit  156 . Processor  152  does not necessarily need to be a microprocessor but could be any component (e.g., a logic circuit, an application specific integrated circuit) capable of determining a dishwasher model type based on an indicator carried by HMI  136  as described below in more detail. As explained above, control programs and variables for many different dishwasher models are stored in memory  154 . The particular control programs and variables executed and utilized by microprocessor  152  depends upon the particular model dishwasher in which control board  150  is installed.  
         [0022]    In accordance with the example embodiment, microprocessor  152  determines which programs and variables to utilize based on an analog input supplied by analog interface circuit  156 . HMI  136  is coupled to analog interface circuit  156 , and HMI  136  includes a connector  158 . A resistor R model  is coupled to connector, and a voltage source (5V) also is coupled to resistor R model  via connector  158 . Resistor R model  has a unique value that is selected based on the dishwasher model type in which HMI  136  is to be used.  
         [0023]    Prior to use, HMI  136  is assembled to a dishwasher door and is electrically coupled to control board  150 . The unique resistor value of resistor R model  impacts the magnitude of the voltage signal sampled by microprocessor  152  from analog interface circuit  156 . More specifically, microprocessor  152  samples the voltage signal at the output of analog interface circuit  156 . Microprocessor  152  then compares the sampled voltage signal with prestored values in memory  154 . Once microprocessor  152  identifies a match (or determines that the sampled voltage signal is within one of a plurality of predefined ranges), then the unique model number that corresponds to the matching value or range is determined to be the model type in which control board  150  is mounted. Microprocessor  152  then executes the appropriate control programs using the appropriate variables for that particular dishwasher model.  
         [0024]    [0024]FIG. 4 is a circuit diagram of an analog interface circuit  156 . Circuit  156  includes resistors R 1  and R 2  as well as a capacitor C 1 . Example values for such components are set forth below.  
         [0025]    R 1 : 3.6 k  
         [0026]    R 2 : 3.32 k  
         [0027]    C 1 : 0.1 uF  
         [0028]    In the specific implementation as shown in FIG. 4 with the circuit component values as set forth above, the following table is applicable  
                                               Model Number   Resistance   Voltage   lower   upper                   0   open   0.0000                1   130,000    0.12380   0.0980   0.1373       2   75,000   0.21069   0.1765   0.2353       3   47,000   0.32798   0.2941   0.3725       4   30,000   0.49541   0.4314   0.5490       5   22,000   0.65207   0.5882   0.7255       6   16,000   0.85790   0.7647   0.9412       7   12,000   1.07827   0.9804   1.1765       8    9,100   1.33045   1.2157   1.4314       9    6,800   1.63345   1.4902   1.7647       10     5,100   1.96405   1.8039   2.0980       11     3,900   2.29143   2.1373   2.4510       12     2,700   2,74980   2.5098   2.9608       13     1,800   3.23516   3.0196   3.4510       14     1,100   3.75000   3.4902   3.9804       15      560   4.39216   4.0196   5.0000                  
 
         [0029]    With the fifteen different resistor values for R model  fifteen different models are discernible based on the analog interface circuit output signal. For example, with a resistor value of 3,900 ohms (model 11), the voltage value at analog interface circuit output should be about 2.29143 Volts, and in a range of 2.1373 Volts to 2.4510 Volts. The range values are stored in a look-up table in memory  154  and microprocessor  152  determines which model corresponds to the range in which the sampled output voltage is within. For example, if the sampled output voltage from analog interface circuit is 2.2402 Volts, then such voltage is within the range corresponding to model 11. Therefore, microprocessor  152  executes uses the variables for a model 11 type dishwasher.  
         [0030]    The above example is expandable. For example, additional pins and resistors can be used to differentiate between more models. If n pins are used with n−1 resistors, then 15 n−1  models can be differentiated.  
         [0031]    The voltage ranges are selected so that variances in component values and input voltages can be accommodated. Accurately selecting the ranges for each model facilitates ensuring the proper program and variables are utilized for the correct dishwasher model. Such ranges can be selected, for example, using empirical data. Also, since the HMI is different for each dishwasher model, the HMI can readily incorporate a unique resistor value corresponding to the particular dishwasher model on which the HMI is to be utilized.  
         [0032]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.