Abstract:
A medical warming cabinet and a method of installing a controller into a medical warming cabinet is disclosed that allows for easy transfer of operation parameters between controllers. Should a controller fail, the removable memory device can be removed from the failed controller and inserted into the replacement controller. This provides the benefits of a generic controller (e.g., low cost and good availability), but eliminates the tedious and costly necessity of having to reprogram the controller during maintenance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/018,372 entitled “CONTROLLER FOR MEDICAL WARMING CABINETS” filed on Dec. 31, 2007 and is a continuation of U.S. patent application Ser. No. 12/250,281 entitled “DATA LOGGER” filed on Oct. 13, 2008. The contents of both of these applications is hereby incorporated by reference as if set forth in their entirety herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention is directed at medical warming cabinets. In particular, this invention is directed at the programming of a controller for a medical warming cabinet. 
         [0004]    Medical warming cabinets may be used to warm blankets, fluids, and the like. Medical warming cabinets must operate under the proper temperatures and parameters to avoid overheating and/or spoilage of the items being heated. To this end, the controllers are often programmed to keep each of the heating compartments within a particular temperature range and to alert the user if there has been non-compliance with the desired heating treatment. In some cases, the end user may be restricted altogether from operating outside of defined operational parameters. 
         [0005]    Often, the controller installed in the medical warming cabinet is a generic controller suitable for use in any one of a number of models. During commissioning, this generic controller is programmed by a skilled technician for the particular cabinet and/or for a particular set of operating parameters. Although the programming of the generic controller is a long and tedious task, the overall cost of a programmed generic controller is typically less than the cost of manufacturing a controller that is unique to a specific medical warming cabinet. 
         [0006]    During the operation life of the medical warming cabinet, some of the components may fail. Most frequently, the failure is not systemic, but rather involves the mechanical failure of a particular component or sub-component. For example, a display screen or user input switch on the controller may fail. However, these types of failures necessitate replacing the entire controller. 
         [0007]    Unfortunately, the replacement of even small broken components require reprogramming the new controller. Given that the service technician may service a number of different models and that even a single incorrect button push may result in improper operation of the cabinet, such reprogramming is particularly error prone. Further, the technician may not have a record of the original operational parameters on hand while reprogramming the cabinet. If the controller is improperly programmed, then an additional service call may be required in order to restore the cabinet to service. 
         [0008]    Hence, there is a need for an improved controller for a medical warming cabinet that is both generic in form and that is easily replaceable. In particular, there is a need for a controller that is less susceptible to programming errors upon replacement of the controller. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    A medical warming cabinet is disclosed. The medical warming cabinet includes a compartment, a heating apparatus for warming the compartment, and a controller configured to operate the heating apparatus. The controller includes a removable memory device connector for receiving a removable memory device. The medical warming cabinet further includes a removable memory device removably received in the removable memory device connector. The removable memory device contains information related to the operational parameters of the medical warming cabinet. The controller, and hence the entire medical warning cabinet, operates according to operational parameters stored on the removable memory device. 
         [0010]    In one form, the controller may include user inputs for altering the information stored on the removable memory device. 
         [0011]    In another form, the medical warming cabinet may also include a data logging module for sampling, storing, and reporting operational data. 
         [0012]    In yet another form, the medical warming cabinet may include at least a first compartment having a first heating apparatus and a second compartment having a second heating apparatus. The removable memory device may contain separate operational parameters for the first compartment and the second compartment. 
         [0013]    In still yet another form, the information on the removable memory device may include heating control algorithm information. 
         [0014]    In another form, the removable memory device may include different operational parameters for different items to be warmed. The controller may have individual temperature controls for irrigation fluids and injection fluids. 
         [0015]    A method of installing a controller into a medical warming cabinet is also disclosed. The method includes providing a controller having a memory device connector and a connector for connecting the controller to a heating apparatus. A removable memory device containing information related to the operational parameters of the medical warming cabinet is also provided. The removable memory device is inserted into the memory device connector on the controller. The controller is installed into the medical warming cabinet. The information on the removable memory device is read by the controller upon operation and the medical warming cabinet operates according to the information stored on the removable memory device. 
         [0016]    In one form, the method may further include the step of operating user inputs on the controller to alter the information stored on the removable memory device. 
         [0017]    In another form, the method may further include sampling operational data using the controller and storing the operational data on a portion of the removable memory device. 
         [0018]    In yet another form, the medical warming cabinet may include at least a first compartment having a first heating apparatus and a second compartment having a second heating apparatus. In this form, the information related to operational parameters of the medical warming cabinet may include separate operational parameters for the first compartment and the second compartment. 
         [0019]    In still yet another form, the information may include heating control algorithm information. 
         [0020]    In another form, the removable memory device may include different operational parameters for different items to be warmed. 
         [0021]    In yet another form, the controller may have individual temperature controls for irrigation fluids and injection fluids. 
         [0022]    Thus, a medical warming cabinet and a method of installing a controller into a medical warming cabinet is disclosed that allows for easy transfer of operation parameters between controllers. Should a controller fail, the removable memory device can be removed from the failed controller and inserted into the replacement controller. This provides the benefits of a generic controller (e.g., low cost and good availability), but eliminates the tedious and costly necessity of having to reprogram the controller during maintenance. 
         [0023]    These and still other advantages of the invention will be apparent from the detailed description and drawings. What follows is merely a description of some preferred embodiments of the present invention. To assess the full scope of the invention the claims should be looked to as these preferred embodiments are not intended to be the only embodiments within the scope of the claims. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a perspective view of a medical warming cabinet with a controller including a removable memory device; 
           [0025]      FIG. 2  is a perspective view of a medical warming cabinet controller with a removable memory device not yet inserted into a socket on the controller; 
           [0026]      FIG. 3  is a perspective view of a medical warming cabinet controller with a removable memory device inserted into the socket; and 
           [0027]      FIG. 4  is a perspective view of a medical warming device controller similar to  FIG. 3 , but in which the controller also has a bus port. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Referring now to  FIG. 1 , a medical warming cabinet  10  includes a door  11  and walls  12  that define a compartment or heating chamber  13 . The heating chamber  13  receives and warms medical items, such as blankets, fluids, and the like. 
         [0029]    The door  11  provides access to the heating chamber  13 . As shown, the door  11  is hinged to the walls  12  by hinges  17 . A door sensor  19  is present that detects whether the door  11  is open or shut. The door sensor  19  may be any kind of sensor including, but not limited to, a mechanical button, switch, or lever that is depressed when the door  11  is closed, an optical sensor, an electrical sensor, a magnetic sensor, and the like. 
         [0030]    A heating apparatus  15  heats the heating chamber  13  and is connected to and controlled by a controller  30 . The heating apparatus  15  can be a heating element, with or without a heat circulating fan, or a low-heat-density electrothermal cable or pad array that is mounted against the inside or outside of the walls  12  define the chamber  13 . 
         [0031]    The controller  30  is configured to operate the heating apparatus  15  at a particular temperature selected by a user. The controller  30  includes a plurality of user inputs  36  and a display  34 . The controller  30  is connected to the door sensor  19  and a temperature sensor  21  for measuring the temperature of the heating chamber  13 . Although the temperature sensor  21  is shown as being placed on a side wall of the heating chamber  13 , it may be placed in any one of a number of positions within the heating chamber  13 . Furthermore, the medical warming cabinet  10  can include an alarm that indicates when a temperature exceeds a temperature that is a certain amount higher than the set temperature. 
         [0032]    A removable memory device  16  is removably received in the controller  30 . Preferably, the removable memory device  16  is not accessible without first disassembling the medical warming cabinet  10 . 
         [0033]    The removable memory device  16  includes information related to the operation of the cabinet  10 . The information can be stored in a configuration file format. The information can include software versions and heating control algorithm information such as allowable temperature ranges and proportional-integral-derivative controller (PID controller) parameters. Depending on the particular application, the information in the configuration file stored on the removable memory device  16  can include, but is not limited to, the type of warmer, the model number, the serial number, the year of manufacturing, the month of manufacturing, the date of manufacturing, the type of warmer (i.e., blanket or fluid), the injection fluids warming minimum temperature, the injection fluids maximum temperature, the irrigation fluids minimum temperature, the irrigation fluids maximum temperature, the blanket minimum temperature, the blanket maximum temperature, PID integration compensation term normalized to 150 degrees F., PID “D” term normalized to 150 degrees F., PID “I” term normalized to 150 degrees F., PID “P” term normalized to 150 degrees F.; PID “D” sampling period in half seconds, check door sensor enable, the frequency of any data collection module, the number of temperature sensors, the output type (e.g., solid state relay or mechanical relay), and control limits for the relay on each side of the setpoint. The temperature parameters can be stored in Fahrenheit, Celsius, Kelvin, or any other scale. 
         [0034]    For fluid warming cabinets, the controller  30  can be configured to allow for individual temperature controls for irrigation fluids (IRR) and injection fluids (INJ). For example, the IRR temperature can be adjusted within a first range and the INJ temperature can be set within a second range, which is typically lower than the IRR range. The appropriate range of temperatures is available automatically once a user selects the type of fluids to be warmed. The user can then input a setpoint within the range of temperatures using the user inputs  36 . 
         [0035]    The controller  30  is further configured to be replaceable, so that if the controller  30  fails, the controller  30  can be removed from the medical warming cabinet  10  and replaced with a new controller. The controller  30  can be configured to be replaceable through the use of removable connectors and lines that connect the controller  30  to the other components of the cabinet  10 , such as a power supply, relays, the heating apparatus  15 , and sensors. Because the removable memory device  16  can be removed from the controller  30  that is being replaced, the removable memory device  16  can be easily inserted into the new controller. Accordingly, the new controller is configured to operate exactly like the failed controller without having to tediously input the control parameters by using the user inputs and without requiring a specialized programming device. Furthermore, the controller  30  can be updated simply by removing an old removable storage device and either updating the old device or inserting a new removable memory device including the updated information. Once the new removable memory device is installed in the controller  30 , the controller  30  loads the information, such as by loading a configuration file, from the removable memory device  16 . In this way, the controller  30  can be also be easily updated. 
         [0036]    For clarity, the removable memory device  16  is not the same as the external memory device that will be described below with respect to the data logging module. The removable memory device  16  is designed to be generally retained in the controller  30  during operation, except when, for example, replacing a faulty controller or upgrading the information for operation of the medical warming cabinet  10 . As described above, replacement typically involves disassembly of the cabinet  10 . In contrast, the external memory device is for offloading data from the cabinet  10 , such as information that has been recorded pertaining to the operation of the cabinet  10 . As will be described below, this periodic transferring of data is intended to be easy accessible by the user. 
         [0037]      FIGS. 2 and 3  show the controller  30  for use with a medical warming cabinet in further detail. The controller  30  includes a removable memory socket  32 , the user display  34 , the user inputs  36 , LEDs  38 , and a plurality of connectors  40  for connection to other components of a warming cabinet. In  FIG. 2 , the removable memory device  16  is shown removed from the removable memory socket  32 . In  FIG. 3 , the removable memory device  16  is shown inserted into the removable memory socket  32 , which can be a bus port. The removable memory device  16  can be a memory chip, memory stick, memory card, and the like. The removable memory socket  32  is configured to allow for the information stored on the removable memory device  16  to be loaded by controller  30 . The controller  30  can comprise a plurality of printed circuit boards including a processor, memory, buses, communication lines, and other electrical components as is well understood in the art. 
         [0038]      FIG. 4  shows a modified version of the controller  30  for use with a medical warming cabinet. As discussed in more detail below, the controller  30  includes a processor and memory device configured to operate as a data logging module. The memory device may be a portion of the removable memory device  16 , memory onboard the controller  30 , or any other type of memory storage. The controller  30  can comprise a plurality of printed circuit boards including a processor, memory, buses, communication lines, and other electrical components as is well understood in the art. The controller  30  is connected by bus lines  60  to a bus port  62 , which is configured to receive a data logging memory device (not shown) that can be read/written by the controller  30 . In one embodiment, the bus port  62  is a universal serial bus (USB) port and memory device is a USB flash drive. The bus port  62  is disposed on the medical warming cabinet  10  to be conveniently accessible without disassembling the medical warming cabinet  10  in which it is installed. 
         [0039]    The data logging module of the controller  30  is configured to log (i.e., sample and record) operational data by sampling data at a predetermined sample rate and storing data packets for each sample. The data packets can include a time/date stamp, the current set point for the compartment  13 , a first measured temperature of the compartment  13  provided by a first temperature sensor (such as temperature sensor  21 ), a second measured temperature of the compartment  13  provided by a second temperature sensor, a state of a door sensor  19  on the warmer, the warmer type, and error logging. All data sampling packets for temperature can be taken from the temperature sensor  21 , but a preferred method is to have an additional sensor and circuitry for independent reporting of the warmer function. In an embodiment, the data packets are sampled at a rate of one per hour and are stored in a memory sized to store six months of data. 
         [0040]    In one embodiment, the memory device is a circular memory buffer. As the operational information is sampled and recorded, the data packets are stored in the circular memory buffer and, when the memory is full, the oldest of the data packets are overwritten during the step of recording. 
         [0041]    The controller  30  can be configured to use the display  34  to indicate that the data logging memory is full and a download is required or as the memory device is reaching capacity. In one embodiment, a message, such as the word “full”, can flash alternately with a displayed temperature of the compartment. When a data logging memory device or external memory device is inserted into the bus port  62 , the controller  30  automatically transfers the logged data to the data logging memory device. The controller  30  indicates on display  34  that the data is being downloaded to the data logging memory device and also indicates when the download has completed. In an embodiment, the display  34  shows “USB DMP” during the download and “USB DONE” once the download has completed and until the data logging memory device has been removed. Once the data logging memory device has been removed, the display function is returned to normal operation. The data can be written to the data logging memory device in a comma delimited format or summarized in a report having. In one embodiment, the user inputs  36  are not locked out when the data is being downloaded. 
         [0042]    The controller  30  can be configured to summarize the logged data in a report format. The report format can be configured to exclude samples that were taken, for example, within two hours of when the door was open or, according to another example, within two hours of when the warmer was turned on. Of course, two hours is only one example and other lengths of time could be selected when determining which samples to exclude from the report. The report can be a text file including the following information: model number, serial number, date of manufacture of unit, date of report/download, software version, frequency a reading was taken, separate report sections for each set point, units, warmer mode, or month change of greater than eight valid readings, and an overall statement summarizing the accuracy of the data and indicating how the data was collected. The separate report section for each set point, units, warmer mode, or month change of greater than eight valid readings including the following information: period of accuracy the section covers, number of days the section covers, number of readings evaluated for the accuracy calculation, number of readings excluded from the accuracy calculation due to the door being opened within a specified time of a reading, mode of warming, warmer accuracy specification, warmer setpoint temperature, average temperature, temperature range, and accuracy evaluation statement indicating if the unit passed or failed to meet the specified accuracy at the selected set point. 
         [0043]    In addition to the features described above, the controller  30  may incorporate other features. The controller  30  can be set by a user to operate in Fahrenheit and Celsius and allows a user to input a temperature within a range of temperatures. The controller  30  can include a timer that allows a user to control when the cabinet turns on and off. The controllers can also have a lock-out feature and a series of prompt sequence indicators. The controllers can also control interior lighting. The cabinet can include a warming shut-off system that is separate from controller and is configured to prevent overheating. 
         [0044]    A warmer can include two compartments that are warmed separately, which allows for flexibility in choosing particular temperatures for warmed blankets or warmed fluids. Combination cabinets can include a blanket warming compartment and a fluid warming compartment. The compartments can be controlled by separate controllers. Alternatively, a single controller can be configured to control more than one compartment. 
         [0045]    While there have been shown and described what is at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention defined by the appended claims.