Abstract:
An apparatus and method for calibration of an FNR lever or multifunction handle (MFH), wherein signal outputs as the FNR lever or MFH is transitioned to and from the neutral position and through at least one range of propulsion positions, are determined. The determined signal values are then compared with benchmark values for the same positions and movements, to determine whether the values are within expected norms. If not, it is determined that a fault condition exists. The operator is also prompted to input acknowledgments when the FNR lever or MFH is at the fully rearward and fully forward positions, to enable the calibration of the lever. Signal values outputted by a neutral switch are sensed when the lever or MFH is initially moved to the neutral position, and at a predetermined time thereafter, to test an associated propulsion enable or latch relay which is configured for providing a predetermined output for a predetermined time after movement of the lever or MFH into the neutral position, to allow for transitioning of the propulsion system to neutral operation.

Description:
[0001]     This application claims the benefit of U.S. Provisional Application No. 60/699,944, filed Jul. 16, 2005. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to equipment calibration and, more particularly, to apparatus and a method embodied in a computer program for calibration of an FNR lever and testing a neutral safety switch in an agricultural windrower.  
       BACKGROUND OF THE INVENTION  
       [0003]     U.S. Pat. No. 6,901,729 is incorporated herein by reference in its entirety. This patent describes a windrower. While other embodiments are possible, it is this general type of windrower that provides the best example of the type of system with which the apparatus and method of the instant invention can/should be used. Provisional Patent Application No. 60/699,944, filed Jul. 16, 2005, is also incorporated herein by reference in its entirety.  
         [0004]     In any modern windrower, and much other similar equipment, it is important to efficient and effective operation that certain system components be calibrated so that outputs can be reasonably relied upon by the operator.  
         [0005]     One such component is the forward-neutral-rearward (FNR) lever, also referred to and as the multi-function handle (MFH). The FNR lever or MFH is an operator controlled component located within the operator platform area or cab, and is manipulated by an operator for controlling propulsion direction and speed. The FNR lever has a neutral position, which is typically a straight up position, and is typically movable from the neutral position forwardly for inputting commands to the windrower propulsion system for effecting forward movements of the windrower, and is movable from the neutral position rearwardly for inputting commands for effecting rearward movements of the windrower. The FNR lever or MFH is an assembly of components, including a sensor device such as a potentiometer which outputs signals, such as a varying voltage to a propulsion system controller, the value of which signal or voltage is a function of the lever position. A suitable conductive path, such as a wiring harness or the like, is provided for communication of the signals. The FNR lever or MFH also typically includes a switch commonly referred to as the neutral safety switch or neutral switch, which is transitioned from one state to another state when the lever or MFH is moved to and from the neutral position. The state of this switch is also communicated to the propulsion system controller via a suitable conductive path, such as a wiring harness or the like.  
         [0006]     Because the FNR lever or MFH is an assemblage of components, and is itself mounted in an assembly, it has been found that there will often be slight variations in output signals between different FNR levers or MFHs, and between different windrowers, such that it is desirable to calibrate the FNR lever or MFH initially before use, after service or replacement, and any time that a fault condition is evident, so as to ensure reliable, accurate outputs.  
         [0007]     Additionally, the FNR lever or MFH, or the circuitry of the propulsion system can include devices such as electrical relays and the like, which can be subject to problems which may negatively effect or degrade the operation of the propulsion system or may be indicators of imminent failure of the device. For instance, at some FNR lever positions it may be desirable for a relay to latch for some predetermined time period, for purposes such as to allow for transitioning operating systems of the propulsion system to a new state. As an example, a system may include a propulsion enable relay which is a latching relay which remains latched for a short period after the FNR lever is moved from a propulsion position (forward or rearward) to the neutral position, to provide continued power for transitioning the propulsion mechanism from a propulsion state to the neutral state. It would thus be desirable to have a capability to reliably detect problems with such devices, as part of a calibration process or routine.  
         [0008]     Therefore, what is sought is an apparatus and method for calibration of an FNR lever or MFH and detection of problems with related devices, to ensure reliable, accurate outputs therefrom.  
       SUMMARY OF THE DISCLOSURE  
       [0009]     According to the invention, an apparatus and method for calibration of an FNR lever or multifunction handle (MFH), to ensure reliable, accurate outputs therefrom, and detection of problems with related devices, such as relays and the like, is disclosed.  
         [0010]     According to a preferred aspect of the invention, the apparatus and method determine signal outputs as the FNR lever or MFH is transitioned from the neutral position to a rearward propulsion position, and from the neutral position to a forward propulsion position. The apparatus and method is also operable for determining signal values outputted as the FNR lever or MFH moves through a range of rearward propulsion positions, and a range of forward propulsion positions, and when the lever or MFH is in the fully rearward and fully forward positions. The determined signal values are then compared with benchmark values for the same positions, to determine whether the values are within expected norms. If not, it is determined that a fault condition exists and a signal representative of the fault condition is outputted to the operator. The fault conditions can be related to the particular signal values that are beyond the expected norm, to facilitate isolation and diagnosis of the problem.  
         [0011]     Additionally according to the invention, the operator is prompted to input acknowledgments when the FNR lever or MFH is at the fully rearward, fully neutral, and fully forward positions, to enable the calibration of the lever.  
         [0012]     Still further according to the invention, signal values outputted by the neutral switch are sensed when the lever or MFH is initially moved to the neutral position, and at a predetermined time thereafter, to test an associated propulsion latch relay which is configured for providing a predetermined output for a predetermined time after movement of the lever or MFH into the neutral position, to allow for transitioning of the propulsion system to neutral operation. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:  
         [0014]      FIG. 1  is a partial side elevational view of a windrower of the type with which the invention may be used, including a header for severing crops from a field, mounted on a front end of the windrower;  
         [0015]      FIG. 2  is a simplified diagrammatic representation of a propulsion driveline of the windrower incorporating aspects of the instant invention;  
         [0016]      FIG. 3  is a schematic of circuitry of a multifunction handle of the windrower;  
         [0017]      FIG. 4  is a schematic of aspects of circuitry of the propulsion driveline;  
         [0018]      FIG. 5  is a schematic of other aspects of circuitry of the propulsion driveline;  
         [0019]      FIG. 6  is a high-level flow diagram illustrating steps of a method of the instant invention;  
         [0020]      FIG. 7  is a continuation of the flow diagram of  FIG. 6 ;  
         [0021]      FIG. 8  is another continuation of the flow diagram of  FIG. 6 ;  
         [0022]      FIG. 9  is another continuation of the flow diagram of  FIG. 6 ;  
         [0023]      FIG. 10  is another continuation of the flow diagram of  FIG. 6 ;  
         [0024]      FIG. 11  is another continuation of the flow diagram of  FIG. 6 ;  
         [0025]      FIG. 12  is a listing of code of a computer program incorporating steps of a preferred embodiment of the method of the invention;  
         [0026]      FIG. 13  is a continuation of the listing;  
         [0027]      FIG. 14  is a continuation of the listing;  
         [0028]      FIG. 15  is a continuation of the listing;  
         [0029]      FIG. 16  is a continuation of the listing;  
         [0030]      FIG. 17  is a continuation of the listing;  
         [0031]      FIG. 18  is a continuation of the listing;  
         [0032]      FIG. 19  is a continuation of the listing;  
         [0033]      FIG. 20  is a continuation of the listing;  
         [0034]      FIG. 21  is a continuation of the listing;  
         [0035]      FIG. 22  is a continuation of the listing;  
         [0036]      FIG. 23  is a continuation of the listing;  
         [0037]      FIG. 24  is a continuation of the listing;  
         [0038]      FIG. 25  is a continuation of the listing;  
         [0039]      FIG. 26  is a continuation of the listing;  
         [0040]      FIG. 27  is a continuation of the listing;  
         [0041]      FIG. 28  is a continuation of the listing;  
         [0042]      FIG. 29  is a continuation of the listing;  
         [0043]      FIG. 30  is a continuation of the listing;  
         [0044]      FIG. 31  is a continuation of the listing;  
         [0045]      FIG. 32  is a continuation of the listing;  
         [0046]      FIG. 33  is a continuation of the listing;  
         [0047]      FIG. 34  is a continuation of the listing;  
         [0048]      FIG. 35  is a continuation of the listing;  
         [0049]      FIG. 36  is a continuation of the listing;  
         [0050]      FIG. 37  is a continuation of the listing;  
         [0051]      FIG. 38  is a continuation of the listing;  
         [0052]      FIG. 39  is a continuation of the listing;  
         [0053]      FIG. 40  is a continuation of the listing;  
         [0054]      FIG. 41  is a continuation of the listing;  
         [0055]      FIG. 42  is a continuation of the listing;  
         [0056]      FIG. 43  is a continuation of the listing;  
         [0057]      FIG. 44  is a continuation of the listing;  
         [0058]      FIG. 45  is a continuation of the listing;  
         [0059]      FIG. 46  is a continuation of the listing;  
         [0060]      FIG. 47  is a continuation of the listing;  
         [0061]      FIG. 48  is a continuation of the listing;  
         [0062]      FIG. 49  is a continuation of the listing;  
         [0063]      FIG. 50  is a continuation of the listing;  
         [0064]      FIG. 51  is a continuation of the listing;  
         [0065]      FIG. 52  is a continuation of the listing;  
         [0066]      FIG. 53  is a continuation of the listing;  
         [0067]      FIG. 54  is a continuation of the listing;  
         [0068]      FIG. 55  is a continuation of the listing;  
         [0069]      FIG. 56  is a continuation of the listing; and  
         [0070]      FIG. 57  is a continuation of the listing. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0071]     Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. Still further, in this description, the terms FNR lever, multi-function handle and MFH referred to the same item, and therefore are interchangeable.  
         [0072]      FIG. 1  shows a self-propelled windrower  10  incorporating the apparatus and method of the invention; however, it will be appreciated that the principles of the present invention are not limited to a self-propelled windrower, or to any specific type of harvesting machine.  
         [0073]     In the illustrated embodiment, the self-propelled windrower  10  comprises a tractor  12  and a header  14 , the header  14  being attached to the front end of the frame  16  or chassis of the tractor  12 . The header may be of generally any suitable construction and design, and may include not only crop-harvesting mechanisms, but also crop conditioners such as elongate rolls  15 . Such attachment of the header  14  to the frame  16  is achieved through a pair of lower arms  18  (only the left one being shown, the right being generally the same) pivoted at one end to the frame  16  and at the other end to the header  14 , as well as through a central upper link  20 .  
         [0074]     One or more cylinders, such as individual lift and flotation cylinders, or a single lift/flotation cylinder, interconnects the lower arm  18  and the frame  16  on each side of the header.  
         [0075]     Typical features and operation of a system for controlling the lift and flotation functions for a header, such as header  14  depicted herein, are disclosed in U.S. Pat. No. 6,901,729, incorporated herein by reference.  
         [0076]     Referring also to  FIGS. 2, 3 ,  4  and  5 , windrower  10  includes a propulsion driveline  22  controllably operable using operator controls for rotatably driving a left wheel  24  and a right wheel  26  for propelling windrower  10  over a ground or other surface. Hydraulic motors (not shown) in connection with each wheel  24  and  26 , respectively, are provided with fluid under pressure by hydraulic pumps  28 , for driving the wheels. The pumps  28  can be differentially controlled for supplying different and varying amounts of pressurized fluid to the hydraulic motors, for effecting desired movements of windrower  10 , including steering movements, as effected by operation of a rotatable and longitudinally movable propulsion rod  30  in connection with pintel arms  32  and  34  movable for controlling displacement of pumps  28  in the well-known manner. Steering commands are inputted to driveline  22  by an operator via an operator control which is a steering wheel  36  disposed in an operator cab  38  of windrower  10 . Steering movements of windrower  10  are effected by rotating respective wheels  24  and  26  at different speeds. Propulsion speed and direction commands are inputted to driveline  22  by an operator via an operator control which is a FNR lever  40  also disposed in cab  38 .  
         [0077]     FNR lever  40  is configured to operate a suitable sensor or sensors operable for generating varying information or outputs representative of the position of lever  40  when lever  40  is manipulated or moved, including a rotary potentiometer  42  and a neutral switch  44 , both of which are connected to a tractor control module  46  via a suitable conductive path or paths  48 , which can be, for instance, a wire or wires of a wiring harness, an optical path, a wireless path, or the like. Movements of FNR lever  40  in relation to the neutral position will cause potentiometer  42  to output varying signals representative of the position of lever  40 , which signals are preferably voltages. It is desired for these voltage signals to very precisely indicate the position of lever  40 , such that precise control of the forward and rearward movements of windrower  10  can be achieved. And, movements of FNR lever  40  into the neutral position, and out of the neutral position, will cause changes in the operating state of switch  44 . Here, forward movements of FNR lever  40  from a generally straight up neutral position shown, will effect a change of state of switch  44  which will be outputted to control module  46 , which will responsively power up the propulsion driveline to propel the windrower in a forward direction, control module  46  controlling the forward speed as a function of the voltage output of potentiometer  42 . Similarly, rearward movement of FNR lever  40  from the neutral position will effect a change of state of switch  44  outputted to control module  46  to affect operation of the propulsion driveline in the reverse direction, and the voltage output of potentiometer  42  will control reverse speed. It is also desired that, when lever  40  is moved into the neutral position, the propulsion system be controlled to de-stroke or otherwise transition into a non-propelling state.  
         [0078]     Other operator controls include a park brake switch  50  also connected to tractor control module  46  via a conductive path  48 , and via another conductive path  48  to a key switch  52  and a start relay  54  in connection with a starter of engine  22  and with tractor control module  46 . A 2-speed switch  56  is connected to tractor control module  46  via another conductive path  48 , as is a field cruise switch  58 .  
         [0079]     Tractor control module  46  is in connection with a rotary potentiometer  62  via a conductive path  48 , potentiometer  62  being operable for outputting information representative of the position of a propulsion cylinder  64 . A rotary potentiometer  66  is operable for outputting information representative of the position of pintel arms  32  and  34  to module  46  via another conductive path  48 . Information representative of speed of respective wheels  24  and  26  is determined by reluctance speed sensors ( FIG. 5 ) and communicated via conductive paths  48  to module  46 .  
         [0080]      FIG. 3  schematically illustrates circuitry  68  of FNR lever  40 .  
         [0081]      FIG. 4  schematically illustrates aspects of propulsion driveline  22  associated primarily with the operator controls, including potentiometer  42 ; neutral switch  44 ; control module  46 ; park brake switch  50 ; speed switch  56 ; and additionally, a park brake latch relay  70 ; a propulsion enable relay  72 , also sometimes referred to as a propulsion latching relay; and a propulsion interlock relay  74 . Other illustrated elements of propulsion driveline  22  include a brake valve solenoid  76  and a ground speed high solenoid  78 .  
         [0082]      FIG. 5  schematically illustrates other aspects of propulsion driveline  22 , including aspects of tractor control module  46  in connection with propulsion cylinder position sensors  80  and  82  which incorporate rotary potentiometer  62  ( FIG. 2 ); a pintel arm position sensor  84  incorporating rotary potentiometer  66  (also  FIG. 2 ); left and right ground speed sensors  86  and  88 ; a propulsion forward solenoid  90 ; and a propulsion reverse solenoid  92 .  
         [0083]     Referring collectively to  FIGS. 2, 3 ,  4  and  5 , this invention involves a method of calibrating and characterizing the operator controls, primarily potentiometer  42  and neutral switch  44 , to enable precise operation of propulsion driveline  22  using FNR lever  40 . More particularly, the method of the invention monitors (1) the potentiometer(s)  42  affixed to the FNR (forward-neutral-reverse) lever  40  that determines, among other things the direction and speed of the vehicle, (2) the FNR neutral switch  44  that determines whether or not the lever is in neutral, and (3) the operational condition (on/off) of the propulsion power and latching circuits. Operational ranges for the various system components are determined by the program designer, and any operation outside of these ranges will cause an destroke of the propulsion driveline or system to automatically occur, i.e., the propulsion drive shaft (shown as the horizontal rod  30  affixed to the two pintel arms  32  and  34  in  FIG. 2 ) is brought to neutral. Destroke is a term used herein to indicate that the drive components are influenced to bring about a quick and controlled deceleration of the vehicle to zero ground speed. Other fault conditions can also be monitored; however, the ones discussed above are the most significant.  
         [0084]     In particular, the invention is incorporated into an operating program that can be run by a processor of tractor control module  46 , or another processor, to monitor fault conditions, such as faults like: FNR potentiometer fault—rate of change out of preset range; FNR neutral switch fault.  
         [0085]     Also referring to  FIGS. 6, 7 ,  8 ,  9 ,  10 , and  11 , a flow diagram  94  illustrating steps of a preferred embodiment of the method according to the invention is shown. Also referring to  FIGS. 12-32 , a listing of code of a computer program incorporating steps of a preferred method of the instant invention, is set forth in written form generally in lines  1 - 870 . Referring to diagram  94 , the calibration procedure begins by first prompting the operator to release the park brake as denoted by block  96  (lines  365 - 373 ). By doing this, propulsion interlock relay  74  will be energized which allows continuity between the propulsion power source and the propulsion circuits that are necessary for this procedure. The proper starting point for the calibration is with the FNR lever  40  (hereinafter MFH) in its neutral position and with the propulsion latching relay  72  deenergized. The control module determines if the MFH is in neutral and whether relay  72  is unlatched as denoted by decision blocks  98  and  102  (lines  379 - 425 ). If it is not, the controller will momentarily remove power in an effort to unlatch the relay, as denoted by block  102  (lines  410 - 425 ), and will also provide a display prompt to the operator as denoted by block  100  (line  384 ), telling him to move the MFH into neutral. When the control module determines that there exists a proper starting point for the procedure, it will prompt the operator to slowly move the MFH to a fully rearward position and press enter, as denoted by block  106  (line  400 ). The controller now seeks to determine, as denoted by decision block  108 , (line  429 ) when the neutral switch  44  transitions as the MFH moves away from its neutral position.  
         [0086]     Following balloon A, at the very moment that neutral switch  44  transitions, the voltage output of potentiometer  42  is recorded as denoted by block  110  (line  431 ) and tested as denoted by decision block  112  (lines  434 - 445 ). If the voltage is not within expected limits the calibration fails as denoted by block  114  (lines  821 - 830 ). When the operator has moved the MFH to its fully rearward position and has pressed the enter key, as denoted by decision block  116  (line  461 ), the voltage output of potentiometer  42  is recorded as denoted by block  118  (line  499 ) and tested as denoted by decision block  120  (lines  485 - 496 ). If the voltage is not within expected limits the calibration fails as denoted by block  122  (lines  821 - 830 ). If the voltage is within expected limits the controller will prompt the operator to slowly move the MFH back to its neutral position, as denoted by block  124  (line  501 ). The controller now seeks to determine, as denoted by decision block  126  (line  516 ), when the neutral switch  44  transitions as the MFH moves back into its neutral position.  
         [0087]     Following balloon B, at the very moment that neutral switch  44  transitions, the voltage output of potentiometer  42  is recorded as denoted by block  128  (line  518 ) and tested as denoted by decision block  130  (lines  521 - 538 ). If the voltage is not within expected limits the calibration fails as denoted by block  132  (lines  821 - 830 ). If the voltage is within expected limits the controller now stops supplying power to the propulsion circuits, as denoted by block  134  (line  550 ), in order to test whether the propulsion latching relay  72  has gone into an unlatched condition, as denoted by decision block  136  (lines  552 - 565 ). If relay  72  remains in a latched condition, the calibration fails as denoted by block  138  (lines  554 - 559 ). Otherwise, the controller determines if the handle is back in a proper starting point for the second half of the calibration procedure, which is with the MFH in its neutral position and with the propulsion latching relay  72  deenergized. The control module determines if the MFH is in neutral and whether relay  72  is unlatched as denoted by decision blocks  140  and  144  (lines  569 - 616 ). If it is not, the controller will momentarily remove power in an effort to unlatch the relay, as denoted by block  146  (lines  600 - 616 ), and will also provide a display prompt to the operator as denoted by block  142  (line  586 ), telling him to move the MFH into neutral. When the control module determines that there exists a proper starting point for the procedure, it will prompt the operator to slowly move the MFH to a fully forward position and press enter, as denoted by block  148  (line  592 ).  
         [0088]     Following balloon C, the controller now seeks to determine, as denoted by decision block  150  (line  621 ), when the neutral switch  44  transitions as the MFH moves away from its neutral position. At the very moment that neutral switch  44  transitions, the voltage output of potentiometer  42  is recorded as denoted by block  152  (line  623 ) and tested as denoted by decision block  154  (lines  626 - 637 ). If the voltage is not within expected limits the calibration fails as denoted by block  156  (lines  821 - 830 ). When the operator has moved the MFH to its fully forward position and has pressed the enter key, as denoted by decision block  158  (line  653 ), the voltage output of potentiometer  42  is recorded as denoted by block  160  (lines  689 ) and tested as denoted by decision block  162  (lines  675 - 686 ). If the voltage is not within expected limits the calibration fails as denoted by block  164  (lines  821 - 830 ).  
         [0089]     Following balloon D, if the voltage is within expected limits the controller will prompt the operator to slowly move the MFH back to its neutral position, as denoted by block  166  (line  691 ). The controller now seeks to determine, as denoted by decision block  168  (line  706 ), when the neutral switch  44  transitions as the MFH moves back into its neutral position. At the very moment that neutral switch  44  transitions, the voltage output of potentiometer  42  is recorded as denoted by block  170  (lines  708 ) and tested as denoted by decision block  172  (lines  711 - 728 ). If the voltage is not within expected limits the calibration fails as denoted by block  174  (lines  821 - 830 ). If the voltage is within expected limits the controller now stops supplying power to the propulsion circuits, as denoted by block  176  (line  740 ), in order to test whether the propulsion latching relay  72  has gone into an unlatched condition, as denoted by decision block  178  (line  744 ). If relay  72  remains in a latched condition, the calibration fails as denoted by block  180  (lines  821 - 830 ).  
         [0090]     Following balloon E, the control module will prompt the operator to pull the MFH fully back to its neutral position and press enter, as denoted by block  184  (line  754 ). When the operator has moved the MFH to its neutral position and has pressed the enter key, as denoted by decision block  186  (line  762 ), the voltage output of potentiometer  42  is recorded as denoted by block  188  (line  764 ) and tested as denoted by decision block  190  (lines  782 - 807 ). If the voltage is not within expected limits the calibration fails as denoted by block  192  (lines  821 - 830 ). If that voltage is within expected limits the controller then tests the neutral switch forward voltages in relation to the neutral switch reverse voltages to see if they are within expected limits, as denoted by decision block  194  (lines  782 - 807 ). If it is not within expected limits the calibration fails as denoted by block  196  (lines  821 - 830 ). If those voltages are within expected limits the calibration procedure is over and it is reported as being successful (line  814 ).  
         [0091]     The following is a sample calibration procedure for a FNR lever or MFH according to the instant invention, referring to propulsion driveline  22 . The voltage values set forth in the following calibration procedure are intended to be illustrative only, and are not to be interpreted as limiting.  
       MFH Calibration Procedure  
       [0000]    
       
          Turn key switch to ON position. Depress and bold both Display Select switches for approx 10 seconds until the Dealer Setup Menu appears on the Display  
          Select and enter into Calibration Mode  
          Select “MFH Position R-18” follow directions on display  
          NOTE: Move MFH slowly, especially when leaving or entering the Neutral area. During the calibration procedure, the MFH potentiometer  42  voltage is always tested for being out of limit high or low. If out of limit, a fault is determined and the calibration fails.  
          The low limit is 0.836 volts.  
          The high limit is 3.832 volts.  
          If the MFH is not at neutral the operator will be prompted to move it to neutral. The Display will read “Slowly Move MFH To Neutral”.  
          The operator will be prompted to switch the park brake off. The Display will read “Calibrating MFH . . . Switch Brake OFF”.  
          The control module tests that neutral switch  44  is open (high voltage at XCM input X002 — 26) and that propulsion enable relay  72  is not energized (low voltage). If so it will read “Slowly Move MFH To Full Rear and Press Enter”. If not the Display will read “Slowly Move MFH To Neutral”. If relay  72  is energized (high voltage) longer than 0.3 seconds after neutral switch  44  is open (high voltage at control module input X002 — 26), then a fault condition is determined and the calibration fails.  
          Going rearward with the MFH the control module records the potentiometer  42  voltage level when neutral switch  44  transitions. The expected voltage range is 2.638±0.203 (2.435 to 2.841).  
          If &lt;2.435, a fault is determined and the calibration fails.  
          If &gt;2.841, a fault is determined and the calibration fails.  
          While going rearward the control module tests that propulsion enable relay  72  is energized (high voltage). If not, a fault is determined and the calibration fails.  
          When the MFH is fully rearward and enter is pressed, the control module tests that neutral switch  44  is open (high voltage at control module input X002 — 26). If not, a fault is determined and the calibration fails. It also tests that relay  72  is energized (high voltage at X001 — 08). If not, a fault is determined and the calibration fails. It then records the potentiometer  42  voltage level. The expected voltage range is 3.544+−0.238 (3.306 to 3.782)  
          If &lt;3.306, a fault is determined and the calibration fails.  
          If &gt;3.782, a fault is determined and the calibration fails.  
          Otherwise the display will read “Slowly Move MFH To Neutral”.  
          Going back to neutral with the MFH the control module tests that relay  72  is energized (high voltage at X001 — 08). If not, a fault is determined and the calibration fails. The control module also records the potentiometer  42  voltage level when neutral switch  44  transitions (high voltage at control module input X002 — 26). The expected voltage range is 2.624±0.213 (2.411 to 2.837).  
          If &lt;2.411, a fault is determined and the calibration fails.  
          If &gt;2.837, a fault is determined and the calibration fails.  
          The control module compares the neutral switch  44  voltage going out of neutral with the neutral switch  44  voltage coming back into neutral.  
          Two conditions must be met. The voltage coming back cannot be greater than the voltage going out and the difference between the two cannot be greater than 0.040 volts.  
          If &gt;0.040, a fault is determined and the calibration fails.  
          The control module stops providing +12 power (X005 — 09) to relay  72  and one second later tests that relay  72  is not energized (low voltage at X001 — 08)). If the power is still there after one second, a fault is determined and the calibration fails. Otherwise the control module tests for switch  44  being open (low voltage at control module input X002 — 26) and relay  72  is not energized (low voltage at X010 — 18). If so it will read  830 ). “Slowly Move MFH To Full Forward and Press Enter”. If not the Display will read “Slowly Move MFH To Neutral”. If relay  72  is energized (high voltage at X001 — 08) longer than 0.3 seconds after neutral switch  44  is open (high voltage at control module input X002 — 26), then a fault condition is determined and the calibration fails.  
          Going forward with the MFH the control module records the potentiometer  42  voltage level when neutral switch  44  transitions. The expected voltage range is 2.371±0.195 (2.176 to 2.566).  
          If &lt;2.176, a fault is determined and the calibration fails.  
          If &gt;2.566, a fault is determined and the calibration fails.  
          While going forward the control module tests that relay  72  is energized (high voltage at X001 — 08). If not a fault is determined and the calibration fails.  
          When fully forward and enter is pressed, the control module tests that neutral switch  44  is open (high voltage at control module input X002 — 26). If not, a fault is determined and the calibration fails. It also tests that relay  72  is energized (high voltage at X001 — 08). If not, a fault is determined and the calibration fails. It then records the potentiometer  42  voltage level. The expected voltage range is 1.116+−0.230 (0.886 to 1.346).  
          If &lt;0.886 a fault is determined and the calibration fails.  
          If &gt;1.346 a fault is determined and the calibration fails.  
          Otherwise the display will read “Slowly Move MFH To Neutral”.  
          Going back to neutral with the MFH the control module tests that relay  72  is energized (high voltage at X001 — 08). If not, a fault is determined and the calibration fails. The control module also records the potentiometer  42  but voltage level when neutral switch  44  transitions (high voltage at control module input X002 — 26). The expected voltage range is 2.383±0.192 (2.191 to 2.575).  
          If &lt;2.191, a fault is determined and the calibration fails.  
          If &gt;2.575, a fault is determined and the calibration fails.  
          The control module compares the S-03 voltage going out of neutral with the S-03 voltage coming back into neutral.  
          Two conditions must be met. The voltage going out cannot be greater than the voltage coming back and the difference between the two cannot be greater than 0.025 volts.  
          If &gt;0.025, a fault is determined and the calibration fails.  
          The control module stops providing +12 power (X005-09) to relay  72  and one-tenth second later tests that relay  72  is not energized (low voltage at X001 — 08)). If the power is still there after one-tenth second, a fault is determined and the calibration fails. Otherwise the Display will read “Pull MFH Fully Back To Neutral And Press Enter”.  
          When enter is pressed at full neutral, the control module records the potentiometer  42  voltage level and the display will read “Calibrating MFH Please Wait . . . ”. The control module then calculates the following:  
       
     
         [0132]     the midpoint between the 2 reverse switchpoints,  
         [0133]     the midpoint between the 2 forward switchpoints,  
         [0134]     the voltage span between the forward and reverse midpoints  
         [0135]     the 25% point and 75% point in that voltage span 
    The control module tests the difference between the forward and reverse midpoints. The expected voltage difference is 0.253+−0.072 (0.181 to 0.325).     If &gt;0.325 volts, a fault is determined and the calibration fails.     If &lt;0.181 volts, a fault is determined and the calibration fails.     The control module also tests the full neutral voltage reading and compares it to the forward and reverse midpoints to see that it is fairly centered (25 to 75%) within the span between the forward and reverse midpoints.     If voltage at neutral&gt;reverse midpoint−25%, a fault is determined and the calibration fails.     If voltage at neutral&lt;forward midpoint+25%, a fault is determined and the calibration fails.     Otherwise the display will read “Calibration Successful”.     Turn key switch to OFF position and keep it off for a minimum of 3 seconds.    
 
         [0144]     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.