Patent Publication Number: US-6658331-B2

Title: Remote control unit for locomotive including display module for displaying command information

Description:
FIELD OF THE INVENTION 
     The present invention relates to remote control units for locomotive and, more particularly, to remote control units for locomotives including display modules for displaying command information such as speed, throttle and brake setting information. 
     BACKGROUND OF THE INVENTION 
     Economic constraints have led railway companies to develop portable units allowing a ground-based operator to remotely control a locomotive in a switching yard. The module is essentially a transmitter communicating with a trail controller on the locomotive by way of a radio link. Typically, the operator carries this module and can perform duties such as coupling, and uncoupling cars while remaining in control of the locomotive movement at all times. This allows for placing the point of control at the point of movement thereby potentially enhancing safety, accuracy and efficiency. 
     Typically, such remote control units include displays indicating the status of the commands being transmitted to the locomotive such as brake setting information, throttle setting information, speed setting information and so on. Generally, the display includes a set of light emitting diodes (LEDs) associated to respective settings corresponding to brake setting information, throttle setting information or speed setting information. For example, a display indicating current brake setting information may include includes six indicators associated to the following brake settings: release; minimum; light; medium; full; charge. The indicators allow the system to display to the operator of the remote control unit  4  levels of the brake setting application (minimum; light; medium; full) in addition to the release and charge settings by turning the corresponding LED “ON” while the other LEDs remain “OFF”. 
     A deficiency with displays of the type described above is that in order to indicate an additional level, an additional LED must be added to the display. Such an addition requires the redesign of the layout of the display module as well as that of the underlying hardware. Such a redesign is costly and therefore limits of the amount of flexibility of the remote control unit. 
     Accordingly, there exists a need in the industry to provide a remote control unit for a locomotive including a display module that alleviates at least some of the problems associated with prior art devices. 
     SUMMARY OF THE INVENTION 
     In accordance with a broad aspect, the present invention provides a remote control unit for controlling a locomotive where the remote control unit includes a manually operable control device, a brake setting display and a display controller in communication with the control device and with the brake setting display. The manually operable control device allows an operator to select a brake setting among a set of brake settings where the brake setting in the set of brake settings correspond to respective levels of brake application. The brake setting display includes an array of discrete display elements. The display controller is responsive to the manually operable control device to actuate a first display element of the array when a first brake setting is selected on the control device, where the first brake setting corresponds to a first level of brake application. The display controller is responsive to the manually operable control device to actuate a second display element adjacent to the first display element when a third brake setting is selected on the control device, where the third brake setting corresponds to a third level of brake application. The display controller is also responsive to the manually operable control device to actuate the first and the second display elements of the array when a second brake setting is selected on the control device. The second brake setting corresponds to a second level of brake application that is intermediate to the first and third levels of brake application. 
     Advantageously, the invention allows expanding the number of brake settings that can be represented on a remote control unit with a given number of discrete display elements without requiring the increasing the number of discrete display elements. 
     In a specific implementation, the array of discrete display elements includes display elements that are linearly arranged. In a non-limiting implementation, the display elements of the array are arranged along a straight line and the display elements of said array are light emitting diodes (LEDs). 
     In a specific implementation, the display module is a moving dot display. In this first specific implementation, when the first brake setting is selected on the control device corresponding to a first level of brake application, the brake setting display actuates the first display element and the second display element is de-actuated. Similarly, when the third brake setting is selected on the control device corresponding to a third level of brake application, the brake setting display actuates the second display element and the first display element is de-actuated. When the second brake setting is selected on the control device, corresponding to the second level of brake application, the brake setting display is operative to actuate the first display element and the second display element in an identical manner. It will be readily apparent that the first display element and the second display element may be actuated is different manners without detracting from the spirit of the invention. 
     In an alternative specific implementation, the display module is a bar graph display. 
     In a specific example of implementation the remote control unit is portable. The remote control unit includes a command generator responsive to the control device to produce a message for causing brakes of the locomotive to be applied at a level corresponding to the brake setting selected at the manually operable control device. The remote control unit includes a transmitter in communication with the command generator for producing an RF signal containing the message. 
     In accordance with another broad aspect, the invention provides a remote control unit for controlling a locomotive including a manually operable control device, a speed setting display and a display controller in communication with the control device and with the speed setting display. The manually operable control device allows an operator to select a speed setting among a set of speed settings. The speed setting display includes an array of discrete display elements. The display controller is to the manually operable control device to actuate a first display element of the array when a first speed setting is selected on the control device. The display controller is to the manually operable control device to actuate a second display element adjacent to the first display element when a third speed setting is selected on the control device. The display controller is to the manually operable control device to actuate the first and second display elements of the array when a second speed setting is selected on the control device, where the second speed setting is intermediate to the first and third speed settings. 
     In accordance with another broad aspect, the invention provides a remote control unit for controlling a locomotive including a manually operable control device, a throttle setting display and a display controller in communication with the control device and with the throttle setting display. The manually operable control device allows an operator to select a throttle setting among a set of throttle settings. The throttle setting display including an array of discrete display elements. The display controller is responsive to the manually operable control device to actuate a first display element of the array when a first throttle setting is selected on the control device. The display controller is responsive to the manually operable control device to actuate a second display element adjacent to the first display element when a third throttle setting is selected on the control device. The display controller is responsive to the manually operable control device to actuate the first and the second display elements of the array when a second throttle setting is selected on the control device, where the second throttle setting being intermediate to the first and the third throttle settings. 
     In accordance with a broad aspect, the present invention provides a remote control unit for controlling a locomotive where the remote control unit includes a manually operable control device, a brake setting display and a display controller in communication with the control device and with the brake setting display. The manually operable control device allows an operator to select a brake setting among a set of brake settings where the brake setting in the set of brake settings correspond to respective levels of brake application. The brake setting display includes an array of discrete display elements. The display controller is responsive to the manually operable control device to actuate a first display element of the array in a first manner of actuation when a first brake setting, corresponding to a first level of brake application, is selected on the control device. The display controller is responsive to the manually operable control device to actuate the first display element in a second manner of actuation when a second brake setting, corresponding to a second level of brake application, is selected on the control device, the second manner of actuation being distinct from the first manner of actuation. 
    
    
     Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram of a locomotive remote control unit in accordance with a non-limiting example of implementation of the present invention; 
     FIG. 2 is a functional block diagram of the diagram of a portion of the remote control unit of FIG. 1 relating to the automatic brake setting selection in accordance with a non-limiting example of implementation of the present invention; 
     FIGS. 3 a  to  3   g  illustrate a first display scheme in accordance with a non-limiting example of implementation of the present invention; 
     FIGS. 4 a  to  4   g  illustrate a second display scheme in accordance with a non-limiting example of implementation of the present invention; 
     FIG. 5 is a block diagram of a display controller in accordance with a non-limiting example of implementation of the present invention; 
     FIGS. 6 a  to  6   h  illustrate a third display scheme in accordance with another non-limiting example of implementation of the present invention. 
     In the drawings, embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings are only for purposes of illustration and as an aid to understanding, and are not intended to be a definition of the limits of the invention. 
    
    
     DETAILED DESCRIPTION 
     Under one possible form of implementation, the remote control unit is illustrated in FIG. 1 of the drawings in accordance with a non-limiting example of implementation of the invention. As depicted, the remote control module  100  is in the form of a portable module comprising a housing  102  that encloses the electronic circuitry (not shown) and a battery (not shown) supplying electrical power to operate the remote control unit  100 . A plurality of manually operable control devices project outside the housing and are provided to allow an operator to select train speed (or throttle), brake, and other possible settings. Such manually operable control devices may be in the form or levers, switches, toggle switches, rotary knobs and push type switches where each actuation of the switch modifies a setting according to a certain pattern amongst others. For additional specific information on this topic and for general information on remote locomotive control systems the reader is invited to consult the U.S. Pat. Nos. 5,511,749 and 5,685,507 granted to CANAC International Inc. and the U.S. Pat. No. 4,582,280 assigned to the Harris Corp. The contents of these documents are incorporated herein by reference. Alternatively, the remote control module can be in the form of a console fixed in a locomotive. 
     As depicted, the remote control module  100  also includes a number of displays including a brake setting display  150  for displaying brake information and a speed setting display  152  for displaying speed setting information. Alternatively, the remote control module  100  may include a throttle setting display (not shown) instead or in addition to the speed setting display for displaying throttle setting information. 
     In a specific embodiment, the remote control unit  100  includes a manually operable control device  104  allowing an operator to select a brake setting among a set of brake settings, the brake settings in the set of brake settings corresponding to respective levels of brake application. The remote control unit  100  includes a manually operable control device  106  allowing an operator to select a speed setting among a set of speed settings. In an alternative specific embodiment (not shown in the figures), the remote control unit  100  includes a manually operable control device allowing an operator to select a throttle setting among a set of throttle settings. 
     The detailed description below refers to the brake setting display  150 . The skilled person in the art will appreciate that the processes and display schemes described herein below may also be applied to the speed setting display  152  and the throttle setting display (not shown) and to the command information displays in general. 
     FIG. 2 shows a functional block diagram a portion of the remote control unit relating to the automatic brake setting selection in accordance with a non-limiting example of implementation. As shown, the remote control unit includes a command generator  216 , a RF transmitter  218 , the manually operable control device  104 , a display controller  202  and the brake setting display  150 . 
     The command generator  216  is responsive to the manually operable control device  104  to produce a message for causing brakes of the locomotive to be applied at a level corresponding to the brake setting selected at the manually operable control device  104 . The command generator  216  is in communication with transmitter  218  for producing an RF signal containing the message and transmitting the message to the locomotive. 
     The display controller  202  is in communication with manually operable control device  104  and with brake setting display  150 . The selected brake setting selected by the manually operable control device  104  is communicated to display controller  202  which causes the current selected brake setting to be displayed to the operator on the brake setting display  150 . 
     The brake setting display  150  includes an array of discrete display elements  200 . The brake setting display shown in FIG. 2 is comprised of six light emitting diodes (LEDs)  204   206   208   210   212   214  forming the array of discrete display elements  200 . The LEDs are associated with the following brake settings: release  214 ; minimum  212 ; light  210 ; medium  208 ; full  206 ; charge  204 . Alternatively, suitable visual indicators other than LEDs may also be used as discrete display elements  200  providing without detracting from the spirit of the invention. It will be appreciated that the number of discrete display elements in the array  200  may vary and that fewer or greater numbers of discrete display elements may be used in different implementations. In a non-limiting example, the display elements that are linearly arranged in the brake setting display  150 . In the implementation shown in FIG. 1, the display elements of the array are arranged along a straight line however diagonal arrangements may also be used without detracting from the spirit of the invention. 
     In a specific implementation, at least part of the discrete display elements are ordered in the array of the display elements  200  in continuously increasing or decreasing order accordingly to the levels of brake application to which the discrete display elements are associated. Ordering the discrete display elements in this fashion provide a visually intuitive display to the user of the remote control unit  100 . In the figures, the brake settings minimum  212 , light  210 , medium  208  and full  206  correspond to respective levels of brake application and are ordered in increasing order of level of brake application from bottom to top. 
     Each discrete display element in the array  200  is adapted to acquire at least two distinct states namely an actuated state and a de-actuated state. The discrete display elements may be actuated in a plurality of different fashions. For the purpose of this specification, a discrete data element is “actuated” by making it visually distinct from other discrete data elements in the group of discrete data elements. In a specific implementation where the discrete data element is a light based indicator, non-limiting examples of actuation manners include: 
     changing the discrete data element&#39;s color or intensity; 
     switching the discrete data elements ON (actuated state) while the non-actuated discrete data elements are OFF (de-actuated state); 
     switching the discrete data elements OFF (actuated state) while the non-actuated discrete data elements are ON (de-actuated state); 
     switching the discrete data elements ON and OFF at a given frequency (flashing) (actuated state); 
     or any other suitable method to visually distinguish the actuated discrete data element from other discrete data elements in the group of discrete data elements. 
     As a variant, each discrete display element in the array  200  is adapted to acquire at plurality of distinct actuated levels in addition to the de-actuated state. In a specific implementation of this variant where the discrete data element is a light based indicator, non-limiting examples of actuation manners include: 
     changing the discrete data element&#39;s to a first color to show a first level of actuation, to a second color to show a second level of actuation and to a third color to show de-actuation; 
     changing the discrete data element&#39;s to a first intensity level to show a first level of actuation, to a second intensity level to show a second level of actuation and to a third intensity level to show de-actuation; 
     switching the discrete data elements ON and OFF at a certain frequency (flashing) for the first level of actuation, switching the discrete data elements ON (second level of actuation) while the non-actuated discrete data elements are OFF; 
     switching the discrete data elements ON and OFF at a given frequency (flashing) for the first level of actuation, switching the discrete data elements OFF (second level of actuation) while the non-actuated discrete data elements are ON; 
     any other suitable method to visually distinguish between the levels of actuation for actuated discrete data elements and de-actuated discrete data elements. 
     In light of the above description, it will be readily apparent that other combinations of examples of actuation to distinguish between different levels of actuation are possible without detracting from the spirit of the invention and as such will not be described further here. 
     Display controller  202  controls the actuation state of each discrete display element in the array of discrete display elements  200  to cause the current selected brake setting to be displayed to the operator on the brake setting display  150 . 
     The display controller  202  implements a display scheme. In addition to the charge setting  204  and the release setting  214 , the display module  150  includes four (4) discrete display element elements corresponding to respective levels of brake application namely minimum  212 ; light  210 ; medium  208  and full  206 . 
     In accordance with a first aspect, the display controller actuates a first display element in the array  200  when a first brake setting corresponding to a first level of brake application is selected on the control device. The display controller actuates a second display element of the array  200  when a third brake setting corresponding to a third level of brake application is selected on the control device  104 . The display controller actuates first and second display elements of the array when a second brake setting corresponding to a second level of brake application that is intermediate to the first and third levels of brake application is selected on the control device. Specific examples of specific implementations of the display scheme implemented by the display controller will better illustrate the above description. 
     In accordance with a first specific implementation of the display scheme, the display controller  202  implements a moving dot display on display module  150 . This will be best understood with reference to FIGS. 3 a - 3   g  of the drawings. 
     In FIG. 3 a , the display module  150  is shown where the first brake setting “Minimum” corresponding to a first level of brake application is selected by the control device. As shown, the display element  212  is actuated and the remaining display elements  210   208   206  are de-actuated. 
     In FIG. 3 c , the display module  150  is shown where the third brake setting “Light” corresponding to a third level of brake application is selected by the control device. The third level of brake application is a greater level of braking than the first level of braking. As shown, the display element  210  is actuated and the remaining display elements  212   208   206  are de-actuated. 
     In FIG. 3 b , the display module  150  is shown where the second brake setting corresponding to a second level of brake application is selected by the control device  104 . The second level of brake application is a level of brake application intermediate to the first and third levels of brake application. As shown, the display elements  210  and  212  are actuated and the remaining display elements  208   206  are de-actuated. In a non-limiting implementation, when the second brake setting is selected on the control device, the brake setting display actuates display elements  210  and  212  in an identical manner. As a variant, the brake setting display actuates display element  210  is a first manner and display element  212  in a second manner distinct from said first manner. 
     In FIG. 3 e , the display module  150  is shown where the fifth brake setting “Medium” corresponding to a fifth level of brake application is selected by the control device. The fifth level of brake application is a greater level of braking than the third level of braking. As shown, the display element  208  is actuated and the remaining display elements  212   210   206  are de-actuated. 
     In FIG. 3 d , the display module  150  is shown where the fourth brake setting corresponding to a fourth level of brake application is selected by the control device  104 . 
     The fourth level of brake application is a level of brake application intermediate to the third and fifth levels of brake application. As shown, the display elements  210  and  208  are actuated and the remaining display elements  212   206  are de-actuated. In a non-limiting implementation, when the fourth brake setting is selected on the control device, the brake setting display actuates display elements  210  and  208  in an identical manner. As a variant, the brake setting display actuates display element  210  is a first manner and display element  208  in a second manner distinct from said first manner. 
     In FIG. 3 f , the display module  150  is shown where the seventh brake setting “Full” corresponding to a seventh level of brake application is selected by the control device. The seventh level of brake application is a greater level of braking than the fifth level of braking. As shown, the display element  206  is actuated and the remaining display elements  212   210   208  are de-actuated. 
     In FIG. 3 g , the display module  150  is shown where the sixth brake setting corresponding to a sixth level of brake application is selected by the control device  104 . The sixth level of brake application is a level of brake application intermediate to the fifth and seventh levels of brake application. As shown, the display elements  206  and  208  are actuated and the remaining display elements  212   210  are de-actuated. In a non-limiting implementation, when the sixth brake setting is selected on the control device, the brake setting display actuates display elements  206  and  208  in an identical manner. As a variant, the brake setting display actuates display element  206  is a first manner and display element  208  in a second manner distinct from said first manner. 
     In this fashion, four discrete display elements  212   210   208   206  display  7  different display settings. In a non-limiting implementation, the control device is adapted to modify the brake setting in the following sequence: 
     from the first brake setting (FIG. 3 a ) to the second brake setting (FIG. 3 b ); and 
     from the second brake setting (FIG. 3 b ) to the third brake setting (FIG. 3 c ); 
     from the third brake setting (FIG. 3 c ) to the fourth brake setting (FIG. 3 d ); 
     from the fourth brake setting (FIG. 3 d ) to the fifth brake setting (FIG. 3 e ); 
     from the fifth brake setting (FIG. 3 e ) to the sixth brake setting (FIG. 3 f ); 
     from the sixth brake setting (FIG. 3 f ) to the seventh brake setting (FIG. 3 g ). 
     In accordance with a second embodiment of the display scheme implemented by display controller  202 , the display module implements a bar graph display on display module  150 . 
     This will be best understood with reference to FIGS. 4 a - 4   g  of the drawings. 
     In FIG. 4 a , the display module  150  is shown where the first brake setting “Minimum” corresponding to a first level of brake application is selected by the control device. As shown, the display element  212  is actuated and the remaining display elements  210   208   206  are de-actuated. 
     In FIG. 4 c , the display module  150  is shown where the third brake setting “Light” corresponding to a third level of brake application is selected by the control device. The third level of brake application is a greater level of braking than the first level of braking. As shown, the display elements  210  and  212  are actuated in the same manner and the remaining display elements  208   206  are de-actuated. 
     In FIG. 4 b , the display module  150  is shown where the second brake setting corresponding to a second level of brake application is selected by the control device  104 . The second level of brake application is a level of brake application intermediate to the first and third levels of brake application. As shown, the display element  210  and  212  are actuated and the remaining display elements  208   206  are de-actuated. When the second brake setting is selected on the control device, the brake setting display actuates display element  210  is a first manner and display element  212  in a second manner distinct from said first manner. In a specific non-limiting implementation, when the second brake setting is selected on the control device, the brake setting display turns “ON” the LED for display element  210  and turns “ON” and “OFF” repetitively (flashing) the LED for display element  212 . 
     In FIG. 4 e , the display module  150  is shown where the fifth brake setting “Medium” corresponding to a fifth level of brake application is selected by the control device. The fifth level of brake application is a greater level of braking than the third level of braking. As shown, the display elements  208   210  and  212  are actuated is a same manner and the remaining display element  206  is de-actuated. 
     In FIG. 4 d , the display module  150  is shown where the fourth brake setting corresponding to a fourth level of brake application is selected by the control device  104 . The fourth level of brake application is a level of brake application intermediate to the third and fifth levels of brake application. As shown, the display elements  212  and  210  are actuated in a first manner and display element  208  is actuated in a second manner distinct from said first manner and the remaining display element  206  is de-actuated. 
     In FIG. 4 g , the display module  150  is shown where the seventh brake setting “Full” corresponding to a seventh level of brake application is selected by the control device. The seventh level of brake application is a greater level of braking than the fifth level of braking. As shown, the display element  212   210   208  and  206  are actuated in a same manner. 
     In FIG. 4 f , the display module  150  is shown where the sixth brake setting corresponding to a sixth level of brake application is selected by the control device  104 . The sixth level of brake application is a level of brake application intermediate to the fifth and seventh levels of brake application. As shown, the display elements  212   210   208  are actuated in a first manner, display element  206  is actuated in a second manner. 
     In accordance with a second aspect, the display controller actuates a display element in the array  200  in a first manner of actuation when a first brake setting corresponding to a first level of brake application is selected on the control device. The display controller actuates the display element of the array  200  in a second manner of actuation when a second brake setting corresponding to a second level of brake application is selected on the control device  104 , the second manner of actuation being distinct from the first manner of actuation. A specific example of specific implementations of a display scheme in accordance with a second aspect will better illustrate the above description. 
     In accordance with a first embodiment of the display scheme implemented by display controller  202 , the display module implements a moving dot display on display module  150 . This will be best understood with reference to FIGS. 6 a - 6   g  of the drawings. 
     In FIG. 6 a , the display module  150  is shown where a first brake setting corresponding to a first level of brake application is selected by the control device. As shown, the display element  212  is actuated in accordance with a first manner of actuation and the remaining display elements  210   208   206  are de-actuated. 
     In FIG. 6 b , the display module  150  is shown where the second brake setting corresponding to a second level of brake application is selected by the control device. The second level of brake application is a greater level of braking than the first level of braking. As shown, the display element  212  is actuated in accordance with a second manner of actuation and the remaining display elements  210   208   206  are de-actuated. 
     In FIG. 6 c , the display module  150  is shown where the third brake setting corresponding to a third level of brake application is selected by the control device  104 . As shown, display element  210  is actuated in accordance with a first manner of actuation and the remaining display elements  212   208   206  are de-actuated. 
     In FIG. 6 d , the display module  150  is shown where the fourth brake setting corresponding to a fourth level of brake application is selected by the control device. The fourth level of brake application is a greater level of braking than the third level of braking. As shown, the display element  210  is actuated in accordance with a second manner of actuation and the remaining display elements  212   208   206  are de-actuated. 
     In FIG. 6 e , the display module  150  is shown where the fifth brake setting corresponding to a fifth level of brake application is selected by the control device  104 . As shown, display element  208  is actuated in accordance with a first manner of actuation and the remaining display elements  212   210   206  are de-actuated. 
     In FIG. 6 f , the display module  150  is shown where the sixth brake setting corresponding to a sixth level of brake application is selected by the control device. The sixth level of brake application is a greater level of braking than the fifth level of braking. As shown, the display element  208  is actuated in accordance with a second manner of actuation and the remaining display elements  212   210   206  are de-actuated. 
     In FIG. 6 g , the display module  150  is shown where the seventh brake setting corresponding to a seventh level of brake application is selected by the control device  104 . As shown, display element  206  is actuated in accordance with a first manner of actuation and the remaining display elements  212   210   208  are de-actuated. 
     In FIG. 6 h , the display module  150  is shown where the eighth brake setting corresponding to an eighth level of brake application is selected by the control device. The eighth level of brake application is a greater level of braking than the seventh level of braking. As shown, the display element  206  is actuated in accordance with a second manner of actuation and the remaining display elements  212   210   208  are de-actuated. 
     In accordance with a second embodiment of the display scheme implemented by display controller  202 , the display module implements a bar graph display on display module  150 . 
     In accordance with this second aspect, four discrete display elements  212   210   208   206  display 8 different display settings. 
     Those skilled in the art should appreciate that in some embodiments of the invention, all or part of the functionality previously described herein with respect to the display controller  202  may be implemented as pre-programmed hardware or firmware elements (e.g., application specific integrated circuits (ASICs), electrically erasable programmable read-only memories (EEPROMs), etc.), or other related components. Optionally, the remote control unit includes a port in communication with the display controller  202  allowing the display scheme implemented by the display controller to be modified by a software component without removing the display controller  202  from the housing  102 . The port may be in any suitable format including but not limited to a serial port, infra-red port, parallel port, modem port, Ethernet port, optical port and USB port. 
     In other embodiments of the invention, all or part of the functionality previously described herein with respect to the display controller  202  may be implemented as software consisting of a series of instructions for execution by a processor. The series of instructions could be stored on a medium which is fixed, tangible and readable directly by the computing unit, (e.g., removable diskette, CD-ROM, ROM, PROM, EPROM or fixed disk), or the instructions could be stored remotely but transmittable to the processor via a modem or other interface device (e.g., a communications adapter) connected to a network over a transmission medium. The transmission medium may be either a tangible medium (e.g., optical or analog communications lines) or a medium implemented using wireless techniques (e.g., microwave, infrared or other transmission schemes). 
     The processor implementing the display controller may be configured as a computing unit of the type depicted in FIG. 5, including a processing unit  502  and a memory  504  connected by a communication bus  508 . The memory  504  includes program instructions  506 . The processing unit  502  is adapted to process the program instructions  506  in order to implement a display scheme described in the specification and depicted in the drawings. The computing unit  500  may also comprise a first interface  510  for communicating with the brake setting display  150  and a second interface  512  with the control device  104 . Optionally, the computing unit  500  may include an additional interface (not shown) for receiving new program element modifying the program instructions  506  in memory  504  for implementing an alternative display scheme. 
     Although various embodiments have been illustrated, this was for the purpose of describing, but not limiting, the invention. Various modifications will become apparent to those skilled in the art and are within the scope of this invention, which is defined more particularly by the attached claims.