Patent Publication Number: US-6216795-B1

Title: Ultrasonic transducer based device positioning system and method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates in general to a method and apparatus to provide an automatic depth and/or height control system, and more particularly to a method and apparatus to automatically control the depth or height position of an agricultural or other mobile tool using a hydraulic system. 
     2. Description of Related Art 
     This invention generally relates to the inventions disclosed within U.S. Pat. No. 4,646,620, and U.S. Pat. No. 4,825,655, which are both incorporated herein in their entirety, that relate to fluid cylinder systems and allow for control of piston stroke positions. 
     Historically, the depth of tool penetration for agricultural equipment, or other soil penetration equipment, has been set by mechanical devices which restrict the retraction or extension of hydraulic cylinders. The cylinder(s) is typically mounted between the frame of the implement and the leg of an implement carrier wheel. Thus, height of the frame above the ground, which determines tool penetration, could be hydraulically changed to a more shallow depth (i.e., less tool penetration) but not to a deeper depth typically because of mechanical restriction. The prior approach is still in use but does not offer good control of material discharge, liquid manure deposits, preparation tillage, ground cover, moisture retention, seed bed preparation or depth of seeding. The prior approach is less desirable because on hard ground the wheels ride up onto the surface, the tools are not set deeper, and this results in shallow tool penetration. On soft ground where the wheels ride deeper, hydraulic corrections can be made with use of manual hydraulics, but fine adjustments are difficult and continuous. 
     Similar issues also exist within similar mobile tools such as sprayer booms, road side grass mowers, and other earth moving, working or discharging equipment. In these other applications, both tool height and depth above the ground is to be controlled. The height and depth measurement for the tool as well as the control system used to the height and depth of these tools are improved by the present invention. 
     Recently, automatic depth control systems have been brought onto the market which control the extension and retraction of the implement carrier cylinders in order to hold a select depth. One such system is disclosed within U.S. Pat. No. 4,646,620. Automatic depth control is controlled by a microprocessor in the tractor cab, sensors on the implement frame and power beyond valving for hydraulic corrections to maintain a given tool penetration. Sensors for this system were depth gauge wheels. 
     Another such system sold by Raven Industries of Sioux Fall, S.D., has a rotary dial on the console to set the working depth. It is difficult to change depth settings on-the-go since selective depths are not programmed. Sensors are Piezo ultrasonic. Power beyond valving requires one of three separate and distinct manifold assembles, either gear pump, pressure compensated or load sensing. This requirement for three separate and distinct valving manifolds for different tractor hydraulic systems is costly; also, the valving is in-line but cannot accommodate manual return flows. Thus, changes from automatic to manual or vice versa require a hoses to be reconfigured. 
     Thus, there is a need for a more efficient system that is more adaptable to on-the-go farming practices and offers better control of depths for operations on varying soil textures (sand, silt and clay), weather affect upon these soils, and control for various implements, applications, and field conditions. 
     SUMMARY OF THE INVENTION 
     To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a console which can detect and switch methodology to either gauge wheel, or ultrasonic sensor. The Console has a LED readout of the rolling average of depth in conjunction with a bar graph depicting variation from the set depth. The bar graph flashes an light outside the WINDOW to denote a hydraulic correction under way. Depth of penetration can be set in inches and {fraction (1/10)} of an inch. 
     Further, a Controller uses a five position détente joy stick to select any of four programmed depths of tool penetration, plus a RAISE position. A Rocker Switch establishes working depths for temporary or permanent memory, with permanent memory made with a SET button. A toggle switch places the system in the RUN mode, where automatic depth corrections are made, or places the system in a HOLD mode wherein no hydraulic corrections can be made. 
     According to another aspect of the invention, there is a hydraulic integrated manifold that is located between the tractor hydraulics and the implement cylinders. This manifold has an arrangement of solenoids and valving that enable the manifold to accommodate all three tractor hydraulic systems presently on the market; namely, Constant Flow Pumps, Pressure Compensated Pumps, and Load Sensing Pumps. This manifold is an in-line mounting that permits double acting flows through it in either direction, manual or automatic operation. Slow flows for hydraulic corrections are set by either an orifice, an adjustable restrictor or proportional valve driven by the Console. An orifice or adjustable restriction incorporates programming which adjusts to overshooting or undershooting of the window by the tool in {fraction (1/10)} of a second increments. The programming adjusts the time in which the tool is connected either earlier or later than optimally necessary to eliminate the overshoot or undershoot. 
     According to still another aspect of this invention, an assembly consisting of a bracket, a potentiometer mechanism and an extending and hinged arm is mounted to the frame of a seeder. The hinged arm is mounted to the seeder leg which in turn is mounted to the seeder frame on one end and carries the seeding mechanism on the other end. This mounting enables a disclosure of angle between the seeder frame and the leg carrying the seeding mechanism. Variations of this angle translate into depth variations. This is a variation of the depth gage wheel. 
     Further, the gauge wheel is an inverted pyramid design which permits the wheel to run approximately two (2) feet ahead of the trailing wheel type. This permits the tire to run on unworked ground, thus preventing, to a degree, mud or soil buildup on the face of the tire which is not now running on worked soil; also the tire does not, then, interfere or inhibit the tools from working mulch. 
     The gauge wheel can be mounted above the implement frame for implements with low clearance (typically 24 inches) or below the frame for implements with high clearance (typically up to 32 inches). 
     Holes placed at one inch intervals permit tension to be placed on the shock absorber. This is a positive positioning, not subject to shipping of plates. 
     According to still another aspect of this invention, an ultrasonic housing is mounted to a swivel or hinge to keep it pointed, by gravity, toward the ground. The electro-static transducer has a cover, commercially referred to as Union Ocean Guard (UOG), over the transducer to protect it against weather, salt, caustic chemicals and overall contamination. It also incorporates a grill to protect it against roughage, such as corn stalks, that could damage the transducer. A vent is provided on the exterior of the transducer insert to prevent pressure buildup (typically 1½ to 2 psi) if the unit becomes hermetically sealed, and also enables ventilation to prevent moisture accumulation and resultant corrosion. Neither the UOG or the grill, ¼×¼, will substantially affect sound wave transmission. A Piezo quartz face transducer is an option for an electrostatic transducer. 
     Thus there have been outlined rather broadly the more important features of the invention in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and will form the subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception on which the disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the invention. It is important, therefore, that the claim be regarded as including such equivalent structures as do not depart from the spirit and scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
     FIG. 1 illustrates a display control panel for a controller unit according to one embodiment of the present invention. 
     FIG. 2 illustrates a joystick input unit according to one embodiment of the present invention. 
     FIGS. 3A-D illustrate various hydraulic systems for use in an automatic depth control system according to an embodiment of the present invention. 
     FIG. 4 illustrates potentiometer-based depth sensor system according to one embodiment of the present invention. 
     FIG. 5 illustrates one potentiometer system according to another embodiment of the present invention. 
     FIG. 6 illustrates a bracket assembly relating to a grain drill according to another embodiment of the present invention. 
     FIG. 7 illustrates an ultrasonic transducer mounting system according to one embodiment of the present invention. 
     FIG. 8 illustrates a wring diagram for gauge wheels according to one embodiment of the present invention. 
     FIG. 9 illustrates a wiring diagram for ultrasonic transducers according to one embodiment of the present invention. 
     FIG. 10 illustrates a wiring diagram for a hydraulic system according to one embodiment of the present invention. 
     FIG. 11 illustrates a system block diagram for an ultrasonic-based automatic depth control system according to another embodiment of the present invention. 
     FIG. 12 illustrates a system block diagram for a console processor apparatus according to another embodiment of the present invention. 
     FIG. 13 illustrates a block diagram for joystick controller system according to another embodiment of the present invention. 
     FIG. 14 illustrates another system block diagram for an ultrasonic-based automatic depth control system according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description of the exemplary embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration the specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention. 
     Referring to FIG. 1 of the drawing, there can be seen an embodiment of the Console. FIG. 1 shows the Console  10  with an On-off switch  11  and a 10 amp Fuse  12 . A three position Console switch  13  has a MANUAL [A] mode that de-energizes all Valve solenoids and enables selective implement depth settings using manual tractor hydraulics; LOCK [B] mode that energizes certain Valve solenoids thereby blocking at the Valve all oil transfers, and placing dynamic tractor oil and flow available at the Valve for automatic Console driven oil transfers; and AUTO [C] mode which transfers control from Console to Controller, where the RUN/HOLD switch is on HOLD. 
     FIG. 1 further shows a WINDOW switch  14  which sets a depth window for no hydraulic correction. This depth window defines a range of depth measurements reported by the depth sensors which is centered around the desired depth in which no correction is made. An LED  15  shows the rolling average depth display. A bargraph  16  indicates deviation, outside the center light, from desired depth. A SENSITIVITY switch  17  is a time delay, one to four seconds, each second being divided into tenths of a second, between an out of depth measurement before a hydraulic correction is initiated. The combination of the WINDOW and SENSITIVITY switch settings permit a user to control the amount of hydraulic correction to be used upon conditions in the field. A DIMMER switch  18  sets the light intensity of lights on the Console. Sensor Lights  19  [A], [B], [C], and [D] indicate the four sensor lights. On-off switches  20  designated as 1 LEFT [a/i), 2 LEFT [b/ii], 3 RIGHT [c/iii] and 4 RIGHT [d/iv] activate or deactivate sensors. An Up/Rephase Switch  21  establishes the time-out for full raise (transport) time for the implement and subsequent rephasing of implement cylinders. Each mark, 1 through 15, on the Rephase Switch establishes a channel for console programming. In one embodiment, sensor lights  19 A-D will blink to indicate the corresponding depth sensor indicates that a portion of the tool is not level. 
     Each of the above switches are shown in the embodiment shown as rotatable switches which permit a variable setting to be selected by user based upon the switches position of rotation. These switches may comprise other switch devices such as a slidable switch or a multi-position switch to achieve the same result without deviating from the scope and spirit of the present invention. 
     FIG. 2 shows the Controller  22  which is connected to the Console by an umbilical cord  23 . A joystick  24  is a five position, mechanical detente switch with SHALLOW [A], SCRATCH [B], SELECT [C], MAX DEPTH [D], and RAISE [E] depth positions. A Rocker Switch  25 , with depth setting positions of RAISE [A] and LOWER [B] sets temporary depth or depth adjustment settings in either a stationary mode or on-the-go. A Set switch  26  which sets a target depth, if pressed within two seconds, as established by the Rocker Switch into permanent memory. A Controller switch  27  which sets RUN [B] or HOLD [A]. 
     FIG. 3A shows three hydraulic integrated manifolds,  50 ,  51  and  52  with all solenoids valves de-energized. A power source  53 , a four way, three position valve  54  with spool positions [A],[B] and [C], connected to a break-a-way  55 . Connecting break-a-way  56  connects to port P 2   57  and line  58  of manifold  50 , which is an optional valve for by-pass oil flow in that it is only used for tractors having a constant flow pump; this manifold can be omitted or its cartridge ports filled with plugs. Line  58  interconnects to line  59  which connects to valve  60  (also referred to as #3), a one way, normally closed solenoid valve, with spool positions [A] and [B], which prevents flow from line  59  to line  61 . Check Valve  62  prevents back pressure in line  63  from flowing into line  61 . 
     Line  58  flows to P 2  Port of the CFP Valve  50  which connects to the corresponding P 2  port of the Automatic Depth Control Valve  51  (ADC Valve). The CFP Valve  50  manifold is only used if the power source, e.g., tractor, has a constant flow pump, which requires a bypass function, as opposed to pressure compensated or load sensing pumps. The CFP Valve  50  and the ADC Valve  51  may either be a single integrated manifold or two separate and independent manifolds connected and secured to each other by O-rings, and bolts running through the CFP valve body and turning into the ADC Valve body. 
     FIG. 3A further shows that line  58  interconnects to line  64  which on one side connects to an Accumulator  65  if shock load reduction is necessary, and on the other side to either a restrictor  66  or instead optionally via inlet line  64  and outlet line  64   a,  a solenoid proportional valve  67  with spool positions [A], [B] and [C]. Optional valve  67  regulates pressure and therefore flow, for restriction, at port [B] relative to the solenoid current. If the optional valve  67  were to be used, then flow through restrictor  66  would be terminated. Line  58  also connects with valve  68 , a two position, normally open solenoid valve with spool positions [A] and [B]. Valve  68  flows to valve  70 , a two position, four way solenoid valve with spool positions [A] and [B] via line  69  which interconnects with line  64 . Valve  70  connects with valve  72 , a normally open solenoid valve with spool positions [A] and [B]. Valve  72  via line  73  interconnects to line  74  which connects to check valve  75 , which connects to line  76  which interconnects to line  77  which connects to load sensing port  78 , and by a third line  79  back to the tractor load sensing port  80 . Line  76  also connects to check valve  81 . 
     Line  73  flows to V 2  port of the ADC Valve  51  which connects to the corresponding V 2  port of the Rebound Valve  52  (RB). The ADC Valve  51  and the RB Valve  52  may either be a single integrated manifold or two separate and independent manifolds connected and secured to each other by O-rings, and bolts running through the RB Valve body and turning into the ADC Valve body. 
     FIG. 3A further shows line  73  interconnects to pilot line  82  of Counter-balance valve  87  and connects with check valve  83  which connects via line  84  to Pressure Reducing and Relieving Valve  85  (PR&amp;R). PR&amp;R Valve  85  connects to drain/pilot line  86  and to reduced pressure line  88  to series cylinder  89  via line  90  to series cylinder  91  via line  92  to series cylinder  93  a typical series cylinder set, via line  94  to C 1  port of RB Valve  52 . 
     FIG. 3A also shows a parallel series cylinder set as optional to a straight series cylinder set. In this option, line  88  connects to line  95  which connects to the piston side of cylinder  96 . Line  97  connects cylinder  96  to the piston side of cylinder  98 . Line  99  connects the rod side of cylinder  98  to the rod side of cylinder  96 . Line  100  connects cylinder  96  to line  94  typically using a torque tube to synchronize the parallel cylinders. Also shown is an option single point hydraulic stroke control valve  101  which controls the retraction of a set of series cylinders or parallel series cylinders. A single point hydraulic stroke control valve can also be replaced by collars attached to the rod of a cylinder in order to control the retraction of the cylinder(s). 
     FIG. 3A further shows line  94  connecting to Counter-Balance Valve  87 . Line  102  interconnects to drain/pilot line  86  of PR&amp;R Valve  85  and pilot line  103  of Check Valve  83 . Line  102  flows to V 1  port of the RB Valve  52  which connects to the corresponding V 1  port of the ADC Valve  51 . Line  102  further continues to intersect line  103  which connects to check valve  81  and connects via line  76  and  77  to Load Sense port  78  which connects to the tractor load sensing port  80  via line  79 . Line  102  continues from the intersection of line  103  to the [A] spool position of valve  70 . From valve  70 , line  104  connects to the P 1  port of the ADC Valve  51  which connects to the corresponding P 1  port of the CFP Valve  50 . Line  104  continues and intersect with line  63  of the CFP Valve. From the intersection with line  63 , line  104  connects with P 1  port (Raise) which connects to break-a-ways  56  and  55 , valving  54  and power supply  53 . 
     FIG. 3B illustrates an alternate embodiment of the hydraulic system according to the present invention in which the pressure reducing valve  85  and has been removed. In all other respects, this less preferred embodiment operates in the manner described above. However, FIG. 3B, this alternate embodiment, has an inherent weakness in that it does not address the problems of compression and de-compression, and draft relief; nor provides a relief for extensive pressure build-up when used in conjunction with mechanical devices limiting stroke of a hydraulic cylinder. 
     FIG. 3C illustrates the operation of the hydraulic system according to a preferred embodiment of the present invention discussed above. During operation, when no hydraulic corrections are underway, the series cylinders can retract  301  from draft forces. The cylinders ingest oil from the tractor oil reservoir via line  313  and  310 , freely flowing through the check valve  83  and PR and RV  85 . Upon relief of the draft forces, the series cylinders re-extend  302 , exhausting oil at a controlled rate of 15 to 20 cubic inches per minute which dampens the effects of draft relief through the PR and RV  85  via line  312  and  313 , returning to the oil reservoir. Oil line  313  is always open to the ingest and exhaust of oil when the hydraulic circuit is in automatic mode. 
     FIG. 3D illustrates the operation of the hydraulic system according to another embodiment of the present invention. According to this embodiment, valve  85  has been replaced with check valve  851 . The operation of the system is again controlled by ingest  321  and exhaust  322 . However, FIG. 3D, this alternate embodiment, has an inherent weakness in that it does not enable the release of detente in the tractor valve during mechanical operation, it back pressures the counter balance valve and single point hydraulic stroke control and results in the hydraulic circuitry not having positive flow channels. The relief valve does not control discharge gpm via line  332  and therefore does not efficiently control the effects of draft relief. 
     FIG. 4 shows a depth gauge wheel assembly  120  having an inverted pyramid arrangement, as an integral depth sensing part of the invention, having a bracket plate  121  coupled to a horizontal support member  402 , the bracket plate having variable hole spacing by which the assembly  120  is fastened to an implement, typically using U-bolts or a bolt plate. A potentiometer assembly  122 , shown in more detail in FIG. 5, senses the angle  401  between the implement frame and the wheel leg extension  123  in order to determine the height of the frame above the ground. A two piece bracket/bolt assembly  124  adjusts and secures the assembly which includes wheel  125  so that the assembly is under tension when the implement tools are just touching the ground surface. A shock absorber  126  assembly provides tension to the assembly and dampens shock loads from uneven ground, clumps of dirt and mulch. The assembly  120  can be mounted either above or below the frame. 
     FIG. 5 shows the potentiometer assembly  122  which incorporates the axle and bearing assembly of depth gauge wheel assembly  120 . A protective housing covers the potentiometer assembly  124  which includes a potentiometer  125 , a potentiometer set arm  126  and a bolt assembly  127  to secure arm  126 . Once assembly  120  is under correct positioning, then assembly  128  is secured by bolt  129  and bolt  130  is aligned opposite bolt  131 . Bolts  132  secure the non-moving bracket assembly  121  to the axle bearing assembly  120 . The electrical grip cord  133  carries the potentiometer  125  voltage signal, that angle between implement frame and wheel assembly  120 , to the Console. The depth of the tool can thus be determined from the measured angle of the sensor. Alternatively, the controller can adjust the operation of the hydraulic system using a measured angle in place of a depth measurement. Because of the geometry of the assembly shown in FIG. 4, the angle measured corresponds directly to the depth of the tool. 
     FIG. 6 shows a bracket assembly  135 , in another integral sensing part of the invention applicable to grain drills, mounted to the frame  136  of a typical grain drill, with bearing and axle assembly  120  and potentiometer assembly  124 . Instead of a wheel leg extension  123  and shock absorber  126  assembly, an arm  137  is welded to axle  120 . Arm  137  incorporates a hinged arm  138  attached to cross arm  139  of grain drill seed arm assembly  140 . Assembly  140  typically includes a double disk opener  141  and a depth gauge wheel or packer wheel  142 , which would locate behind the disk opener  141 . 
     FIG. 7 shows the ultrasonic transducer  170  which is attached to the frame  171  of the implement. The ultrasonic transducer may be used in addition to, or in place of, the potentiometer sensor for obtaining depth measurements of the tool. The transducer generates a signal which is transmitted to the controller that is proportional to the distance between the transducer mounted on the frame and the ground. In one particular embodiment, this tranducer element comprises a tranducer manufactured by Senix Corp., of Bristol, Vt., Model No. UA-TR-ENU. By measuring this signal, the controller may obtain a measure of the depth of a tool in the soil. A swivel housing  172  mounts on the implement frame. A swivel bracket  173  extends outward onto which is attached rubber mounts  174  for the transducer assembly  175 . Rubber mounts  174  provide give for sensor clearance on an implement plugged by mulch. The farmer backs up the implement to discharge the plug and then drives back over the plug to spread it. Transducer housing guard  176  protects against mulch entering the housing. The hinge bracket or swivel  173 , which permits the transducer housing to always point toward the ground such as when an implement wing is raised, is attached to bracket  176  and the housing cap  177  of transducer housing  175 . Cap  177  permits the removal of transducer insert  182 . The transducer insert  182  holds the transducer  183 , an optional protective covering  184 , such as Union Ocean Guard material, for the transducer face, and a venting port  185  and an optional protective grill  186  of approximately ¼×¼ grid. 
     FIG. 8 illustrates a wiring diagram for gauge wheels potentiometer based sensors ( 841 - 843 ). This wiring harness consists of three segments. The first segment  802  runs between the Console unit and connector  801  and an intermediate quick disconnect  810 . The second segment  812  runs from a quick disconnect  811 , which mates with quick disconnect  810 , and disconnect  820 . A third segment comprises three separate links  822 ,  823 , and  824  which run between quick disconnect  821  and three separate connectors  830 ,  831 , and  832 . Disconnect  821  mates with disconnect  820  to complete the length from Console unit to each of the potentiometers. 
     FIG. 9 illustrates a wiring diagram for the ultrasonic sensor system according to one embodiment of the present invention. The first of several wiring harnesses  902  runs between a quick disconnect  901  and a quick disconnect  910 . The quick disconnect  901  interfaces with the Console unit of the controller. 
     The second segment of this wiring harness  912  runs between quick disconnect  911  and control box  920 . Quick disconnect  911  connects with quick disconnect  910  on the first segment  902  to connect the Console with the ultrasonic control box  920 . 
     A series of connections run from the control box  920  to each of the ultrasonic transducers ( 952 - 955 ). The first of these connections  921  run between the control box  920  and a temperature sensor  931 . A plurality of additional connections  922 - 925  run between the control box  920  and a series of mating connectors  932 - 935 . These run control signals out from a control box towards the transducers. The transducers are attached to disconnects  942 - 945  providing a direct connection from these transducers all the way into the control box. 
     FIG. 10 illustrates a wiring diagram for the hydraulic valving according to one embodiment of the present invention. The wiring harness consists of a first segment  1002  which runs between quick disconnect  1001  and intermediate connect  1003 . The  1001  connector connects to the Console unit to connect the controller to the hydraulic wiring harness. A second wiring segment comprising a plurality of connections  1011 - 1014  runs between quick disconnect  1010  and each of the valves themselves. Disconnect  1010  connects to disconnect  1003  for connecting the wiring harness from the Console to the valves themselves. The controller within the Console effectuates operation of the individual valves by sending control signals down this harness to each of the valves individually. 
     FIG. 11 illustrates a block diagram of the complete depth control system according to one embodiment in the present invention. The system consists of the Console controller  1101  and its corresponding user operated joystick  1102 . The Console and its controller are connected to ultrasonic sensor system  1103  and a hydraulic subsystem  1104 . The ultrasonic subsystem  1103  comprises three wiring segments  1110 ,  1111 , and  1113 , the ultrasonic drive control unit  1112 , and a plurality of ultrasonic sensors  1114 - 1117 . The wiring connection for this subsystem corresponds to the wiring shown in FIG. 9 discussed above. 
     The hydraulic subsystem comprises a plurality of wiring harnesses  1120 - 1124 , a CFP adapter  1125 , a hydraulic server  1126 , and rebound valve  1127 . The wiring connections for the hydraulic subsystem  1104  correspond to the wiring shown previously in FIG.  10 . 
     The controller contained with Console  1101  comprises electronics support or microprocessor based subsystem running software which obtains depth measurements from the ultrasonic sensors  1114 - 1117  on a periodic basis and adjusts the depth of the implement using the hydraulic subsystem  1104 . The ultrasonic subsystem  1103  could, in fact, be replaced by the potentiometer base system using the gauge wheels as shown in FIGS. 4 and 8 respectively. 
     SET-UP OPERATION 
     The Set-Up operation of system FIG.  1  and FIG. 2 is explained as follows: 
     a. With the implement connected to the tractor, tractor with the engine running, use the tractor hydraulics  53 - 54  to place the implement in the raised or transport position, and then return the tractor hydraulic lever  54  in the neutral position. 
     b. Turn Console  10  to the switch  11  “ON” position and move the Console Toggle  13  to the MANUAL [A] position which de-energizes valves  60 ,  68 ,  70  and  72 . The LED  15  shows “H.H” if the Controller  22  toggle switch  27  is not on HOLD [A]; the LED  15  shows a negative number, e.g. “−9” showing height above the surface if the Controller  22  toggle switch  27  is on HOLD [A]. This is a safety step and the ADS will not set up functions unless switch  27  is on HOLD [A]. 
     c. Press applicable DEPTH SENSOR switches  20 , [a], [b], [c] and [d], to activate sensors. Applicable LEDs  19 , [A], [B], [C] and [D] will light to show sensors are activated. 
     d. Lower tillage tool just onto the ground surface and establish surface as a permanent memory reference (actual ground zero for tool replacement) by pressing the SET button for ten (10) seconds (ten is programmable). LED will flash 0.0 twice as permanent set point signal. All depth settings SHALLOW, SCRATCH, and SELECT are relative to reference “SURFACE.” 
     e. Move the Controller  22  joystick  24  to the SCRATCH (B) depth position. Use the Rocker Switch  25  to choose a working SCRATCH (B) depth; e.g., a depth of 0.5 inches to till, for example, wet ground only 0.5 inches deep so it starts to dry but does not chunk. Press and hold the SET  26  button within two seconds. The LED will read “0.5” and the SCRATCH setting is now in permanent memory. 
     f. Move the Controller  22  joystick  24  to the Shallow [A] depth position. Use the Rocker Switch  25  to choose a working SHALLOW [A] depth; e.g., a depth of 1.5 inches to erase the tractor tire lug marks on a 180 degree turn at the end of a field. Press and hold the Set  26  button within two seconds. The LED  15  will read “1.5” and the SHALLOW setting is now in permanent memory. 
     g. Move the Controller  22  joystick  24  to the SELECT [C] depth position. Use the Rocker Switch  25  to choose a working SELECT [C] depth; e.g., a depth of 3.5 inches which is the depth at which the field may be tilled. Press and hold the Set  26  button within two seconds. The LED  15  will read “3.5” and the SELECT setting is now in permanent memory. 
     h. RAISE [E] is an automatic position and will place the implement in the raise or transport position. It is also a position for rephasing of cylinders, a cylinder rod position which removes air from the hydraulic circuitry. 
     i. MAX [D] is an automatic position and will place the implement in the deepest tillage possible, either onto depth stops or to full cylinder rod retraction. There is a timed sequence for dynamic hydraulics. 
     j. Use the WINDOW  14  rotary switch to select an underground spread in which no hydraulic corrections will be made; e.g., ½ inch would provide a depth window, plus or minus ¼ inch, before a hydraulic correct would take place. Each light from center is always ½ of the previous variation. 
     k. Use the SENSITIVITY  17  rotary switch to set the time delay for hydraulic correction; e.g., if a variation of depth outside the Window restriction of ½ inch does not remain outside ½ inch for an example period of time of (1) second, approx. 10 feet at 7 mph, no hydraulic correction would take place. Also, if the sensors showed a depth variation outside the WINDOW for less than one second (example), but a return inside the Window within the second, then no hydraulic correction would take place. 
     l. Use the rotary dial Up- Rephase  22  to select the time required to fully raise the carrier cylinders, either series or parallel series; plus rephase series cylinders to exhaust any air trapped in the system. This is a time sequence for dynamic hydraulics. 
     FIELD OPERATION 
     Surface, Scratch Shallow and Select depth values are in permanent memory from the set-up operation. 
     a. Turn the Console  10  to the switch  11  “On” position. SURFACE, SCRATCH SHALLOW and SELECT; e.g., “0.0”, “0.5”, “1.5” and “3.5” will be displayed in sequence, each two times, then depressed within two seconds within the sequence. 
     b. Place the Console Toggle switch  13  on LOCK [B] (the Controller toggle  27  must be on HOLD [A] or the LED  15  will read “H.H” and functions cannot start—a safety feature). 
     c. Press each applicable DEPTH SENSORS  19  switch [a], [b], [c], and [d] to activate applicable sensors. LED  15  will display averaged depth, or display “—.—” for a position above ground, or “9.9” for a position 9.9 inches deep or deeper. 
     d. With Console toggle  13  on LOCK [B] and Controller toggle  27  on HOLD [A], secure tractor hydraulic valve  54  in spool position [A] to provide dynamic pressure to P 2 . Move Console toggle switch  13  from LOCK [B] to AUTO [C]. The Controller  22  now controls the automatic operation. 
     e. Controller  22 —Set joystick  24  to either RAISE, SHALLOW or SELECT. The tractor is in gear and moving. Move Controller toggle  27  from HOLD [A] to RUN [B] and the implement will go to the depth indicated by joystick  24  detent setting. Moving the joystick  24 , on-the-go, to any one of the detent positions and hydraulics will actuate the cylinders to reach this depth or raise position. 
     f. The MAX [D] is a special, maximum depth setting and must be deeper than Select [C] depth. It moves cylinders in a retract mode to the deepest tillage setting of the implement, either onto a single point hydraulic depth control stop, mechanical depth stops or to fill retraction of the cylinders 
     g. The Rocker Switch  25  is a special depth setting function in that it overrides all depth settings except HOLD  27 [A]. Rocker switch  25  depth changes go into temporary memory. To place the new depth setting into permanent memory press and hold the Controller  22  Set Button  26  within two seconds. If Set Button  26  is not actuated than any temporary memory of the Rocker Switch  25  will cancel upon the joystick  24  being moved to another position. 
     
       
         
           
               
            
               
                   
               
               
                 POWER BEYOND VALVE SEQUENCE 
               
            
           
           
               
               
               
               
            
               
                   
                   
                   
                 Patent 
               
               
                   
                   
                 Valve(s) 
                 Valve 
               
               
                 Function 
                 Mode 
                 Energized 
                 Number 
               
               
                   
               
               
                 MANUAL 
                 No. 1 
                 None 
                 None 
               
               
                 LOCK &amp; HOLD 
                 No. 2 
                 #2 &amp; #3 
                 60 &amp; 72 
               
               
                 RAISE 
                 No. 3 
                 #4 
                 70 
               
               
                 RAISE to tillage 
                 No. 4 
                 None 
                 None 
               
               
                 Raise - incremental 
                 No. 5 
                 #4 &amp; #5 (#9) 
                 70 &amp; 68 (67) 
               
               
                 Lower - incremental 
                 No. 6 
                 #5 (#9) 
                 68 (67) 
               
               
                 Raise by Rocker Switch 
                 No. 5 
                 #4 &amp; #5 (#9) 
                 70 &amp; 68 (67) 
               
               
                 Lower by Rocker Switch 
                 No. 6 
                 #5 (#9) 
                 68 (67) 
               
               
                 MECHANICAL 
                 No. 7 
                 None 
                 None 
               
               
                   
               
            
           
         
       
     
     Between all modes, there is restricted flow, microprocessor adjusted, by {fraction (1/10)} of a second periods to prevent overshooting and/or undershooting of the WINDOW. When tool penetration enters the Window spread, Mode #2 secures the depth. Mechanical depth is always full flow hydraulics with dynamic pressure holding for typically 6 sec from SURFACE, 4 sec from SHALLOW, and 3 sec from SELECT. After this time elapse, Mode #2 secures the depth. 
     Here is given a typical field tillage operation addressing variable soil conditions. With a power source such as a tractor, pulling a trailing implement such as a cultivator, the following sequences of automatic depth control would take place through interaction of the Console, Controller, Power Beyond Valving, Gauge Wheels or Ultrasonics. A person versed in hydraulics can readily follow the hydraulic circuitry. The Console  10  is on and set and the Controller  23  has control of the automatic mode. 
     1. The joystick  24  is moved from RAISE [E] to SELECT [C], a depth of 3.5″. Mode No. 4 lowers, Mode No. 6 slows, and Mode No. 2 secures 3.5″ 
     2. The joystick  24  is moved from SELECT [C] to SHALLOW [A], a depth of 1.5″. Mode No. 3 raises, Mode No. 5 slows, and Mode No. 2 secures 1.5″. 
     3. The joystick  24  is moved from SHALLOW [A] to SELECT [C], a depth of 3.5″. Mode No. 4 lowers, Mode No. 6 slows, and Mode No. 2 secures 3.5″. 
     4. The joystick  24  is moved from SELECT [C] to SCRATCH [B], a depth of 0.5″. Mode No. 3 raises, Mode No. 5 slows, and Mode No. 2 secures 0.5″. 
     5. The joystick  24  is moved from SCRATCH [B] to SELECT [C], a depth of 3.5″. Mode No. 4 lowers, Mode No. 6 slows, and Mode No. 2 secures 3.5″. 
     6. The Rocker Switch  25  changes SELECT [C] depth to 3″. Mode No. 5 changes depth to 3″ at one click for each {fraction (1/10)}″. 
     7. The joystick  24  is moved from SELECT [C] to MAX DEPTH [D]. Mode No. 7 lowers implement onto mechanical stop devices. Hydraulic pressure remains dynamic in lowering mode for timed seconds. 
     8. The joystick  24  is moved from MAX DEPTH [D] to RAISE [E]. Mode No. 3 raises implement to fill raise—transport position. Hydraulic pressure remains dynamic for time set on UP/REPHASE  21 . 
     FIELD SHUT DOWN 
     1. Move joystick  24  to RAISE [E]—this places implement in the transport mode 
     2. Move Controller toggle  27  switch to HOLD [A] 
     3. Move Console Toggle  13  to LOCK [B] 
     4. Center hydraulic valve  54  to spool position [B] 
     5. Switch Console  10  switch  11  to Off 
     All values set in permanent memory remain in permanent memory; therefore, it is mandatory that SURFACE always be an accurate value. Every time an operator enters a field, he should feel obligated to verify the SURFACE setting. 
     MANUAL OPERATION 
     There may be times or circumstances when it is desirable to run in a manual operation. The automatic depth control system will give depth reading, if Console  10  switch  11  is “On” and appropriate DEPTH SENSORS  19 , [a], [b], [c] and [d] are on, but all hydraulic functions will be made by the operator. 
     1. Move Controller toggle  27  to HOLD [A] 
     2. Center hydraulic valve  54 , spool [B] position 
     3. Move Console toggle  13  to MANUAL [A] 
     4. Use hydraulic valve  54  for manual adjustments of tool penetration. 
     CONSOLE CONTROLLER 
     During operation, the operation of the depth control system is under the operational control of a programmable processing system within the console unit. FIG.  12 . illustrates an example embodiment of a processor system. The console controller  1200  comprises a processor  1201  which interfaces with a number of components to control the depth control system. The controller  1200  receives is electrical power from a connection  1204  to a battery which passes through a fuse  1206  and on/off switch  1203 . The power source is regulated  1205  to provide the required voltage levels for all of the electronics. 
     The processor  1201  receives various inputs signals from the window potentiometer  1231  and the sensitivity potentiometer  1232 . These signals perform the parameter input functions discussed above to control the operation of the depth control system. The processor  1201  also receives input signals from the gauge wheel sensors  1210 - 1211  to sense the current height of the device. The processor  1201  receives input signals from the four console keyboard switches  1202  to receive user input settings as described above. 
     The processor  1201  interfaces with the joystick  1221  through a joystick interface  1220 . The joystick  1221  is used to remotely control the operation of the depth control system by providing a convenient user interface to the system. The processor  1201  possesses an RS-232 serial interface  1250  to an ultrasonic position measurement unit  1252 . Finally, the processor also receives input signals from the up/rephase 16 position switch  1230 . 
     Turning the Rephase Knob will select different set-up/test modes. Positions 0-3 are READ only, and positions 4-15 can be changed by using the rocker switch. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Po- 
                   
                   
               
               
                 sition 
                 Function 
                 Comments 
               
               
                   
               
             
            
               
                 0 - 
                 reads the voltage provided 
                 This number should be 
               
               
                   
                 to the system. 
                 multiplied by 10. 
               
               
                   
                   
                 i.e. 1.2 = 12 volts. 
               
               
                 1 - 
                 reads the input pot #1, 
                 0 to FF, no scaling, 
               
               
                   
                   
                 to test if pot is functioning. 
               
               
                 2 - 
                 reads the input pot #2, 
                 0 to FF, no scaling, 
               
               
                   
                   
                 to test if pot is functioning. 
               
               
                 3 - 
                 reads the input pot #3, 
                 0 to FF, no scaling, 
               
               
                   
                   
                 to test if pot is functioning. 
               
               
                 4 - 
                 (R: 0.0-9.9) 
                 The time in which 
               
               
                   
                   
                 RUN/HOLD/RUN needs 
               
               
                   
                   
                 to be switched in 
               
               
                   
                   
                 to show settings. 
               
               
                 5 - 
                 (R: 0.0-1.1) 1.1 = 3 
                 Gage wheels (1L, 2LC, 3RC), 
               
               
                   
                   
                 0.0 = 4 Gage wheels (+4R). 
               
               
                 6 - 
                 (R: 0.0-9.9) 
                 Time in sec before setting 
               
               
                   
                   
                 ground (0.0) calibration. 
               
               
                 7 - 
                 (R: 0.0-1.1) sets the 
                 0.0 = off, 1.1 = on. 
               
               
                   
                 buzzer on or off, 
                   
               
               
                 8 - 
                 (R: 0.0-9.9) sets the 
                 The range is 0.0 to 9.9 inches. 
               
               
                   
                 Signal Average Drop off. 
                   
               
               
                 9 - 
                 (R: 0.0-9.9) 
                 From 0 to 99%. So a 9.0 is 90%. 
               
               
                   
                 Threshold value for noting 
                   
               
               
                   
                 if a pot has fallen off. 
                   
               
               
                 10 -  
                 (R: 0.0-9.9) Sets the 
                 From 0.0 to 9.9 seconds 
               
               
                   
                 LED update time. 
                 (Bar graph time = 
               
               
                   
                   
                 ½ LED time). 
               
               
                 11 -  
                 OPEN 
                 FUTURE USE. 
               
               
                 12 -  
                 (R: 0.0-9.9) Sets 
                 The range is 0.0 to 9.9 seconds. 
               
               
                   
                 mechanical depth time out. 
                   
               
               
                 13 -  
                 (R: 0.0-9.9) Fast 
                 The range is {fraction (1/10)} of a second. 
               
               
                   
                 Correction Threshold. 
                   
               
               
                 14 -  
                 (R: 0.0-9.9) Post Scaling 
                 The range is from 0.0 to 9.9. 
               
               
                   
                 in mv/(.1 inch). 
                 This number should be multiplied by 
               
               
                   
                   
                 ten to convert to mv/(.1 inch). 
               
               
                   
                   
                 i.e. 2.0 = 20 mv/(.1 inch). 
               
               
                 15 -  
                 (R: 0.0-9.9) Sample time, 
                 This number should be 
               
               
                   
                 of 32 data. 
                 multiplied by 3.2. 
               
               
                   
               
            
           
         
       
     
     The Ultrasonic Measurement Module (UMM) serial input possesses four external analog inputs. The four external analog inputs shall measure voltage amplitudes from zero Vdc to +5.00 Vdc using an 8-bit A/D converter located in the processor. The total resolution shall be plus or minus 1 Least-Significant-Bit (LSB) of the A/D converter which is plus or minus 20 millivolts. Transzorb diodes will protect these inputs from over voltages exceeding +30 Vdc. A Sensor Reference (+5.00 Vdc) shall be provided for potentiometers. 
     This input shall be a RS-232 compatible input to the processor at 9600 baud. Standard RS-232 interfaces will be used to allow the Input to physically connect an Ultrasonic Measurement Module Input to the processor  1201 . 
     The UMM also possess three “on-off” coil driver outputs and an output. A total of three “on-off” low side coil driver outputs shall be provided to drive three valve coils, Coils  2 / 3 ,  4  and  5 , at 12 Vdc and/or 24 Vdc. No PWM or dither shall be provided for these outputs. Coil currents of up to 1.8 Amperes shall be handled by these drivers on Coil  4 . Coil  2 / 3  and Coil  5  driver shall drive up to 3.6 Amperes. Each driver shall withstand a short circuit without damage and restore its operation when the short is removed. Short circuits shall be detected and reported to the processor which will turn off the coil. 
     The Ultrasonic Serial Output is a RS-232 compatible output from the processor  1201  at 9600 baud. Standard RS-232 interfaces will be used to allow the output to physically connect an Ultrasonic Measurement Module to the processor. 
     The processor  1201  generates output signals which are transmitted to a display  1240  to provide information to a user. In one embodiment, the display comprises a plurality of seven-segment display elements to permit the display of various numerals and characters. This display unit may consist of any display device for providing information to a user without deviating from the spirit and scope of the present invention. In one embodiment, the display possesses a dimmer  1241  and a 7 led bar graph  1242 . 
     The processor  1201  also generates output signals to control the various hydraulic valves ( 1268 - 1270 ). These signals are transmitted to various valve drivers  1265 - 1267  to provide the proper electrical signals from the digital processor to these valves through driver interface circuits  1260 - 1261 . The processor uses these circuits to control the operation of the valves to adjust the height of the depth control system. 
     FIG. 13 illustrates a circuit diagram for the joystick unit. This unit corresponds to the joystick unit shown in FIG.  2 . When the joystick is moved to each of the four positions, SCRATCH, SHALLOW, RAISE, and MAX-DEPTH, the corresponding switches  1301 - 1304  are closed by the joystick unit. The closure of each of these switches generates a signal to the joystick interface  1220  for communication to the processor  1201 . The unit also possess a SET  1326 , UP/DOWN  1325  and RUN-HOLD  1327  switch which correspond to these same switches illustrated on FIG.  2 . 
     Structured software design practices shall be employed in the present invention. Top-down design of all major modules may accomplished by writing a Software Definition Document which describes all major modules in detail. The modules may be coded in C which will then compile to assembly-level coding for the processor  1201 . 
     The Basic Input-Output System (BIOS) consists of the following blocks: 1) Reset module, 2) Analog to Digital Converter input module, 3) RS232 input module, 4) Valve driver  2 / 3  output module, 5) Valve drivers  4  and  5  output module, 6) Audible alarm output module, 7) Keypad input module, 8) UP/Rephase switch module, 9) Two-digit display output module, 10) Keyboard and Valve activity indicators output module, 11) Valve enable control module, 12) Seven LED Bar Graph output module and 13) Output register module. 
     Reset Module 
     The following devices are reset to an off state: Valve driver  2 / 3  output module, Valve drivers  4  and  5  output module, Audible alarm output module, Keyboard indicators and Valve activity indicators, Seven LED bar graph output module, Output register control module and Valve enable control module. The Up/rephase switch is configured as an input function. The RS232 Input/Output module is initialized for full duplex, 9600 baud operation. The Keyboard input module is configured to receive and decode key depressions from the Joystick and the Front pane. The Mode Switch is decoded as being in the LOCKED position. The Analog to Digital Converter module is turned off. 
     Analog to Digital Converter Module 
     The Analog to Digital Converter when enabled, converts eight channels of analog information, using a mux address to enable an input Channel (AN 0  to AN 7 ) and then converts an analog voltage to a digital number 0 to 255 as in section 2.1 (Eight bit resolution). Channel AN 7  receives the valve of the Left Sensor # 1  (0 to +4.99 Vdc typical). Channel AN 6  receives the valve of the Left Sensor # 2 . Channel AN 5  receives the value of the Right Sensor # 3 . Channel AN 4  receives the value of the Right Sensor # 4 . Channel AN 3  receives the value of a TOTAL SPAN potentiometer. Channel AN 2  receives the value of a DAMPEN potentiometer. For both potentiometers, 0 Vdc equals ccw position and +5 Vdc equals fill clockwise position. Thus, the 295 degrees of potentiometer rotation is divided into 256 steps. Channel AN 1  receives a divided by 10 value of the vehicle power voltage. Values of 0 Vdc to +51.1 Vdc can be read, thus each bit represents 0.2 Vdc or 200 millivolts DC. Channel AN 0  reads the Reference Voltage output as seen by the Input Channel potentiometers. Its normal range is +4.75 to +5.25 Vdc and is also Vref voltage for the A/D converter system. 
     RS232 Input/Output Module 
     The RS232 Input/Output module uses the SCI module of the ADC processor to implement a full-duplex RS232 9600 baud communications interface. The default mode on reset shall enable UMM operation. 
     Valve Driver  2 / 3  Output Module 
     The Valve driver  2 / 3  output module is a standard HCT “on-off” non-current feedback module. A latch controls whether valves  2 / 3 ,  4  and  5  are enabled. Prior to Valve operation, a short circuit detector comparitor must be “reset”. Signal SHORT 23 H, is reset as an output, by being pulsed LOW (logic 0=0 Vdc) for 50 milliseconds, then be converted to an input to detect a short circuit condition for Valves  2  or  3 . The maximum current prior to current shut-down is 8.33 Amperes. The valve draws 40 Watts or 3.9 Amperes. 
     Valve Drivers  4  and  5  Output Module 
     The Valve drivers  4  and  5  output module is a standard HCT dual “on-off” non-current feedback module. A latch controls whether valves  2 / 3 ,  4  and  5  are enabled. Signal SHORT 45 H, is reset as an output by being pulsed LOW (logic 0=0 Vdc) for 50 milliseconds, and converted to a input to detect a short circuit condition for Valves  4  or  5 . Either Vale  4  or Valve  5  may be on or both may be on. The maximum current prior to current shut-down is 8.3 Amperes. These valves do not draw the same current. Valve  4  will draw 1.9 Amperes while Valve  5  will draw 3.6 Amperes, when on. Worst case current draw is 5.4 Amperes. 
     Audible Alarm Output Module 
     The Audible alarm output module is used when 1) the LOCK positions is engaged either by the processor  1201  or the Joystick Controller, 2) when there is a key pressed or when 3) special functions are engaged. The LOCK alarm indication is a steady tone until the controller is out of the LOCK position The key press alarm position is a 100 millisecond beep tone. 
     Keyboard Input Module 
     This module decodes the Mode Switch, the 4 Membrane panel keys and the Joystick Controller. The default position of the Mode Switch is the LOCK position. Upon reset, the processor  1201  will be in the LOCK mode for safety reasons. The other modes of the Mode Switch are AUTO and MANUAL. 7 of the 11 switches are the Open or closed type, while the 4 DEPTH SENSOR switches are of the “Toggle” type. These switches are turned off upon ADC reset. When the sensors are set up (i.e. turned ON), depressing the switch will “toggle” the sensor on and turn “ON” the GREEN indicator LED above the switch. Depressing the switch a second time will turn the sensor “OFF” and the LED “OFF.” Key repeats are allowed for only the “toggle” functions. 
     Up/Rephase Switch Input Module 
     This module inputs UP/REPHASE switch position. 
     Two-Digit Display Output Module 
     The two digit display module is two seven segment displays which show inches, 0 to 9, and tenths of inches, 0.1 to 0.9, respectively. Thus, depths of 0.0 to 9.9 inches will be shown on the display. Numbers of 0 through 9 and several special characters must be outputted to latches. Numbers 0 through −9 inches (integer values) may also be shown. 
     Keyboard and Valve Activity Indicators Output Module 
     Seven LEDS are controlled by this module. A buffered bit BPC 0  signal controls a RIGHT SENSOR # 4  indicator, D 104 . A logic “1” on this bit turns on the indicator and a logic “0” turns off the indicator. Similarly, a BPC 1  signal controls a LEFT SENSOR # 2  indicator. A BPC 2  signal controls a LEFT SENSOR # 1  indicator. A BPC 3  signal controls a RIGHT SENSOR # 4  indicator. LEDS are located on the Membrane switch panel. A BCP 4  signal controls the Valve  2 / 3  Activity indicator, which is located on the processor circuit card assembly. A steady RED indication shows that the Valve  2 / 3  is on, while a flashing RED indication (one per second) shows that Valve  2 / 3  is shorted. The logic levels are the same for the Valve indicators as they are for the membrane panel indicators. A BPC 6  signal controls the Valve  4  Activity indicator and a BPC 7  signal controls the Valve  5  Activity indicator. These indicators all operate identically to the Valve  2 / 3  activity indicator. These indicators are all latched on or off into a register. 
     Valve Enable Control Module 
     Three bits control the operation of Valves  2 / 3 ,  4  and  5 . Three bits of the buffered data bus are used to latch on or off the respective valve(s). These bits are latched into register U 20  under Output Register control. 
     Seven LED Bar Graph Output Module 
     The seven LED bar graph, in the normal operating mode, lights one of the seven LEDs to indicate span and deviation. 
     Output Register Control Module 
     The data for the Two-digit seven segment display, the Seven LED bar graph, the Keyboard and Valve Activity Indicators and the Valve Enable control are all latched into external registers using a one of four decoder and a Timer on the processor to generate a strobe pulse. Signals PA 0  and PA 1  are used to generate an address to decode a strobe pulse for latching the respective data on the buffered data bus to the proper device. The Timer output pulse should be at least 1 microsecond long when latching is desired. Strobe output G 0 H latches the Units (Inches) into a register to display the depth in inches. Strobe output G 2 H signal latches the Keyboard and Valve Activity indicators into a register. Strobe output G 2 H signal also enables Valves  2 , 3 ,  4  and  5  in a Register. Strobe output G 3 H signal latches the date for the Seven LED bar graph. 
     FIG. 14 illustrates a complete system diagram for the controller system comprising a joystick unit  1401 , a console unit  1402 , and a power switch  1410 . The console  1402  interfaces with the ultrasonic transceivers through a serial connection  1420 . The console  1402  receives the analog input signals from the gauge wheels through interface  1440  and generates and receives signals to the hydraulic system through connection  1430 . 
     The foregoing description of the exemplary embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not with this detailed description, but rather by the claims appended hereto.