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A control system and method of controlling a conveyor-type dishwasher is disclosed, with the dishwasher including a plurality of sequentially arranged work stations, each of the stations performing an operation on ware located therein such as washing, rinsing, drying and the like. A conveyor carries

A control system and method of controlling a conveyor-type dishwasher is disclosed, with the dishwasher including a plurality of sequentially arranged work stations, each of the stations performing an operation on ware located therein such as washing, rinsing, drying and the like. A conveyor carries the ware into the dishwasher, past each of the stations, and out of the dishwasher. A sensor mounted at a reference point adjacent the conveyor near the entrance for ware to the dishwasher senses the presence of ware items on the conveyor as the items are carried past the reference point. Positional advance of the conveyor is monitored to define a current conveyor position and track movement of the items through the dishwasher. Controls responsive to the sensor start operations within each of the stations in response to movement of the conveyor sufficient to carry items from the reference point to the station, and stop operations in response to movement of the conveyor sufficient to carry the items from the station.

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1. A control system for conveyor-type dishwasher having a plurality of sequentially arranged work stations, each of said stations having means for performing an operation on ware items located therein such as washing, rinsing, drying and the like, and a conveyor for carrying the ware items into said

1. A control system for conveyor-type dishwasher having a plurality of sequentially arranged work stations, each of said stations having means for performing an operation on ware items located therein such as washing, rinsing, drying and the like, and a conveyor for carrying the ware items into said dishwasher, past each of said stations, and out of said dishwasher, whereby each of the ware items has defined therefor a leading edge and a trailing edge, said control system comprising: sensor means mounted at a reference point adjacent said conveyor near the entrance for ware to said dishwasher for sensing the presence of ware items on said conveyor as the items are carried thereby past said reference point; means for monitoring positional advance of said conveyor for defining a current conveyor position and tracking movement of said items through said dishwasher; control means responsive to said sensor means and said monitoring means for starting said operation performing means within each of said stations in response to movement of said conveyor sufficient to carry said items from said reference point to said station, and for stopping said operation performing means in response to movement of said conveyor sufficient to carry said items from said station; said monitoring means including means for defining a series of zones of equal size arranged sequentially along said conveyor in the direction of travel of the ware for movement with said conveyor, and means for providing a count having an initial count value and increasing said value incrementally for movement of each zone past said reference point to produce a changing current count value; the distance along said conveyor from said reference point to the entrance to one of said stations being defined as a first integer number of said zones, and the distance along said conveyor from said reference point to the exit of said one station being defined as a second integer number of said zones; said sensor means senses the presence of a leading edge and a trailing edge of a ware item as said ware item is moved past said reference point; said control means is operative to, upon sensing the presence of said leading edge, add said first number to the current value of said count to produce a first start value, and to store and first start value; said control means is operative to, upon sensing the presence of said trailing edge, add said second number to the current value of said count to produce a first stop value, and to store said first stop value; and said control means is further operative to, upon the current value of said count becoming equal to said first start value, commence operation within said one station, and upon the current value of said count becoming equal to said first stop value, halt operation within said one station. 2. The control system as defined in claim 1, wherein, upon production by said control means of said first start value and said first stop value, and in the event an additional stop value has been previously stored whose value is greater than or equal to said first start value but less than said first stop value, said control means is operative to eliminate said additional stop value. 3. The control system as defined in claim 1 wherein, upon the current value of said count becoming equal to said first stop value, and in the event an additional start value has been stored whose value is greater than said first start value but less than or equal to said stop value, said control means is operative to continue rather than halt operation within said one station. 4. A control system for a conveyor-type dishwasher having a plurality of sequentially arranged work stations, each of said stations having means for performing an operation on ware items located therein such as washing, rinsing, drying and the like, a conveyor for carrying the ware items into said dishwasher, past each of said stations, and out of said dishwasher whereby each of the ware items has defined therefor a leading edge and a trailing edge, and a reference point defined adjacent said conveyor near the entrance for ware to said dishwasher, said control system comprising: means for defining a series of zones of equal size arranged sequentially along said conveyor in the direction of travel of the ware for movement with said conveyor; means for providing a count value having an initial count value and for increasing said value incrementally upon movement of each of said zones past said reference point to produce a changing count value; the distance along said conveyor from said reference point to the entrance to one of said stations being defined as a first integer number of said zones, and the distance along said conveyor from said reference point to the exit of said one station being defined as a second integer number of said zones; sensor means for sensing the presence of a leading edge and a trailing edge of a ware item as said ware item is moved past said reference point; and control means responsive to said sensor means and said count means for, upon sensing the presence of said leading edge, adding said first number to the current value of said count to produce a first start value and storing said first start value upon sensing the presence of said trailing edge, adding said second number to the current value of said count to produce a first stop value and storing said first stop value, and in the event an additonal stop value has been previously stored whose value is greater than or equal to said first start value but less than said first stop value, eliminating said additional stop value; said control means further being constructed to control the operation performing means at said one station such that upon the current value of said count becoming equal to said start value, operation within said one station is commenced, and upon the current value of said count becoming equal to said first first stop value, operation within said one station is halted. 5. The control system as defined in claim 4, wherein said control means is further constructed such that said first start value is stored unless an additional start value has been previously stored and said first start value is greater than said additional start value and less than said additional stop value, whereupon said first start value is eliminated. 6. The control system as defined in claim 4, wherein said zone defining means includes a plurality of markers mounted in an equally-spaced series for movement along a movement path during movement of said conveyor, and detector means mounted adjacent said movement path for detecting the passage of each of said markers and generating a signal pulse in response thereto, each of said zones being defined as the portion of said conveyor moving past said reference point between two successive ones of said signal pulses. 7. The control system as defined in claim 6, wherein said count means includes said markers and said detector means, said count value being increased incrementally upon generation of each of said signal pulses. 8. The control system as defined in claim 7, wherein said dishwasher further includes a motor and drive means connecting said motor with said conveyor for driving said conveyor, and wherein said zone defining means further includes a member driven by said drive means, said markers being mounted on said member. 9. The control system as defined in claim 8, wherein each of said markers includes a magnet and said detector means includes a Hall effect switch. 10. The control system as defined in claim 8, wherein said sensor means includes source means mounted adjacent said conveyor substantially at said reference point for generating a beam of elecromagnetic radiation and directing said beam across said conveyor, and receiving means mounted across said conveyor from said source means for continuously receiving said beam except when a ware item moved past said reference point by said conveyor interrupts said beam, thereby indicating the presence of said item. 11. The control system as defined in claim 10, wherein said beam is directed across said conveyor at other than a right angle to the conveyor path. 12. The control system as defined in claim 4, wherein said sensor means is operative to define a positive status in which ware is present at said reference point and a negative status in which no ware is present, and wherein said control means is responsive to said sensor means by determining a current status of said sensor means at uniform timed intervals of predetermined duration, said duration being selected such that a plurality of said intervals will occur as each of said zones is moved past said reference point. 13. The control system as defined in claim 4, further comprising switch means connected with said control means, said control means being responsive to said switch means such that upon actuating of said switch means, said control means ignores said first start value and said first stop value and causes said operation performing means within said one station to operate whenever said conveyor is in operation. 14. A method of controlling a conveyor-type dishwasher having a plurality of sequentially arranged work stations for performing operations on ware items located therein comprising washing, rinsing, drying operations and a conveyor for carrying the ware items into said dishwasher, past each of said stations, and out of said dishwasher, whereby each of the ware items has defined thereon a leading edge and a trailing edge, the method comprising the steps of: defining a reference point along said conveyor near the entrance for ware to said dishwasher; defining a series of zones of equal size arranged sequentially along said conveyor in the direction of travel of the ware for movement with said conveyor; providing a count having an initial value and increasing said value incrementally for movement of each zone from said reference point to produce a changing current value; determining, as a first number of said zones, the distance from said reference point to the entrance to one of said stations, and as a second number of said zones, the distance from said reference point to the exit from said one station; sensing to detect the presence of a leading edge and a trailing edge of a ware item ware items as said ware item is moved past said reference point; upon detecting the presence of said ledging edge, adding said first number to the current value of said count to produce a start value, and storing said start value, upon detecting the presence of said trailing edge, adding said second number to the current value of said count to produce a first stop value and storing said first stop value and, in the event an additional stop value has been previously stored whose value is greater than or equal to said start value but less than said first stop value, eliminating said additional stop value; upon the current value of said count becoming equal to said first start value, commencing operation within said one station; and upon the current value of said count becoming equal to said stop value, halting operation within said one station.