CA1167145A - Sprayer flowmeter - Google Patents
Sprayer flowmeterInfo
- Publication number
- CA1167145A CA1167145A CA000363076A CA363076A CA1167145A CA 1167145 A CA1167145 A CA 1167145A CA 000363076 A CA000363076 A CA 000363076A CA 363076 A CA363076 A CA 363076A CA 1167145 A CA1167145 A CA 1167145A
- Authority
- CA
- Canada
- Prior art keywords
- signal
- speed
- spray
- pulses
- signals
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01M—CATCHING, TRAPPING OR SCARING OF ANIMALS; APPARATUS FOR THE DESTRUCTION OF NOXIOUS ANIMALS OR NOXIOUS PLANTS
- A01M7/00—Special adaptations or arrangements of liquid-spraying apparatus for purposes covered by this subclass
- A01M7/0089—Regulating or controlling systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F9/00—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine
- G01F9/001—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine with electric, electro-mechanic or electronic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F9/00—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine
- G01F9/02—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine wherein the other variable is the speed of a vehicle
- G01F9/023—Measuring volume flow relative to another variable, e.g. of liquid fuel for an engine wherein the other variable is the speed of a vehicle with electric, electro-mechanic or electronic means
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Insects & Arthropods (AREA)
- Pest Control & Pesticides (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Special Spraying Apparatus (AREA)
- Measuring Volume Flow (AREA)
Abstract
SPRAYER FLOWMETER ABSTRACT OF THE DISCLOSURE A sprayer monitor for indicating to a field sprayer operator various parameters such as the rate of application of fluid, the volume applied, the true ground speed, the area covered, etc. The monitor provides improved accuracy since the apparatus has the facility of being calibrated under actual field conditions, rather than using assumed input parameters. Speed and fluid flow pulse signals related to assumed vehicle speed and fluid flow rate are applied to a control circuit which has constants stored during calibration. With an additional stored constant related to the spray width, the control circuit determines the aforenoted parameters as a function of the calibration constants and applies signals to a display.
Description
t~ r~j ~)1 1 02 Tnis lnv~n~i~n rela~e~ to agricuLtural e~ulpm~nt, an~
~3 parti~ularly to a Inonitor ~or a ~ s~rayer, ~UC~I as a ~n~mical 04 spra~er.
05 The spray application of chemicals such a~ ~r-t~ rs, 06 pesticides, etc., to the field requires careful con-trol, in order 07 to optimize the rate of applicàtion. This is desirable bo-th to 08 minimize cost and to apply the reco~lmended concentration.
09 The sprayer operator normally calculates the rate oE
application of the chemical to be sprayed by establishing a flow 11 rate from his mobile storage tank to the spray nozzles, measuring 12 the width of the spray, and establishing a certain rate of speed 13 of the spray vehicle. The field area covered within a given time 14 period allows him to calculate the volume of fluid per unit area which ha~ been applied (e.g. gallons per acre).
16 While the application rate, with a given vehicle speed, 17 can be calculated before spraying, should the flow rate change 18 during spraying due to a build up of residue in the fluid pipes, 19 should a change in vehicle speed be desired, etc., it would be a difficult and tedious task to maintain a continuous calculation 21 effort in the field, which would be re~uired to ensure that the 22 required application rate is maintained. Consequently apparatus 23 has been made available to the sprayer operator which performs 24 the calculation automatically and provides an indication of certain parameters to him, such as the area covered, the number 26 of gallons per acre applied, etc. In such prior art apparatus 27 flow of the spray fluid is measured as well as the vehicle speed, 28 and knowing the spray width which is utilized, charts or other 29 indicators provide an output indication.
In one such prior art device, in order to measure 31 vehicle speed an electromagnetic detector is used to detect 32 a metallic discontinuity or a magnet applied to a vehicle wheel.
33 The rotation rate of the wheel is converted by the apparatus into 34 vehicle speed. Calibration for the wheel circumference is done by thumb~wheel switch. A water flowmeter provides an electrical 36 signal which is alleged to be proportional to the amount of fluid 37 flowing to the spray heads. This apparatus calculates applied 38 gallons per acre.
39 In another such device, a photosensor is used to ~, ' 02 sense markings on the vehicle wheel, to determine i-ts ro-tation 03 rate and thus the speed of the vehicle. Alternatively, an 04 outboard wheel which Eo:Llows the vehicle is used to determine the 05 ground speed. This apparatus also :includes means to synchronize 06 the spray bar pressure with ground .speed via a servo control 07 valve.
08 The sprayer monitors utilizing the above-noted vehicle 09 speed sensors all have a deficiency in common, that is, that the rate of application data given to the farmer is determined by a 11 parameter which is not an accurate representation of the 12 parameter purported to be represented. E'or example ground speed 13 is determined by -the rotation rate oE a wheel or the rotation 14 rate of a shaft. Where the ground is soEt or the tire inflation pressure of the tractor or vehicle wheel is low, the vehicle 16 wheel will rotate a greater number of times for a given linear ~7 distance than if the inflation pressure were higher or the ground 18 firmer. The chemical flow rate per unit time might then be 19 increased, resulting in wasteage of spray fluid.
Where an outboard wheel is used, mud and debris can 21 impede its smooth operation, and it can be subject to bounce, 22 thus reducing its accuracy.
23 The present invention, on the other hand, allows the 24 sprayer operator to calibrate his vehicle and spray apparatus directly, the calibration constants being stored by the 26 apparatus, thus giving him a substantially improved accuracy of 27 spray application.
28 The present invention provides the sprayer operator 29 with an accurate measurement of the rate of fluid application, the total volume applied, the true ground speed, the area 31 covered, the spray rate, and the distance travelled. Calibration 32 is controlled at the vehicle driver's seat.
33 In the present invention the ground speed sensor is a 34 metal detector which detects metal targets or discontinuities on a wheel or on any rotating part which has its speed related to 36 ground speed. A circuit determines the distance travelled as 37 each target passes and the ground speed is computed. Means is 38 further provided to calibrate the ground speed, with tire size, 39 tire pressure and soil compaction effects automatically accounted , 7~.a,~
0]. 3 02 and compensated for, resulting in a more accura-te representation 03 of the ground speed than in the prior art.
04 The fluid flow rate is determined by a flowmeter in the 05 Eluid flow line leading to -the spray bar carrying the spray 06 heads. A pulsing signal sent from the flowmeter is proportional 07 to the volume pumped per unit time. The width of the spray line 08 is entered into the apparatus by pu!~hbutton. A digital display 09 provides the output to the operator.
Clearly the application rate is de-termined by how fast 11 an area is covered and by the quant:ity of chemical sprayed. The 12 present invention multiplies signal represen-ting the speed and 13 width, and the result is divided into the flow rate to obtain the 14 rate of application of the fluid. All other outputs provided to the operator are obtained from the three measurements noted 16 above, of speed, flow rate and width. Since the width can be 17 determined by actual measurement, and is normally relatively 18 stable, and both flow rate and speed are calibrated by actual 19 tests or by manually input-ting constants relating to particular fields, for example, the present apparatus has been found to have 21 considerably improved accuracy over prior art apparatus.
22 The invention, in general, is a sprayer monitor for 23 spray vehicles comprising a sensor for sensing the speed of 24 the sprayer and for providing a first signal representative of the speed, a sensor for sensing the rate of flow of a ~luid to be 26 sprayed and for providing a second signal representative of the 27 rate of flow, a memory for storing a third signal representative 28 of the width of the sprayer, a display, and a control circuit for 29 receiving the signals and for generating a display operating signal and applying it to the display, which corresponds to the 31 value of the second signal divided by the product of the first 32 and third signals, representing the volume of fluid sprayed per 33 unit area.
34 More particularly, the invention is a sprayer monitor for a spray vehicle comprising: a circuit for receiving a speed 36 indication signal comprising a plurality of pulses, the frequency 37 of the pulses being related by a predetermined speed factor 38 signal to the actual speed of the vehicle, a circuit for 39 receiving a fluid flow indication signal comprising a plurality ~ `
7 ~1 ~A r j 02 o pulses, the frequency oE the pulses being related by a 03 predetermined flow factor signal to the actual spray fluid flow 04 rate, a memory for storing signals represen-tative of the spray 05 width of the sprayer, and said speed and flow factor signals, a 06 display, and a control circuit connected to the display, the 07 receiving circuit and the memory Eor generating a signal 08 representing a number of speed indication pulses received in a 09 predetermined time and a further signal representing a number of fluid flow indication pulses received in a predetermined time, 11 and for applying the speed factor signal to the signal 12 representing the number of speed indication pulses received in a 13 predetermined time to obtain an actual speed signal, and for 14 applying the flow factor signal to the signal representing the number of fluid flow indication pulses received in a 16 predetermined time to obtain an actual fluid flow rate signal, 17 for multiplying the speed signal and the width signal and for 18 dividing the result into the fluid flow rate signal to obtain a 19 signal representative of -the volume of fluid applied per unit area, and for applying the latter signal to the display.
21 A better understanding of the invention will be 22 obtained by reference to the description of the preferred 23 embodiment of the invention described in detail below and to the 24 following drawings, in which:
Figure 1 is a general view of a tractor with a spray 26 bar attachment with which the present invention is used, 27 Figure 2 is a general pictorial view of the invention, 28 Figure 3 is a general block diagram of the invention, 29 Figure 4 is a logic schematic of the invention, and Figures 5A, 5B, 6A, 6B, 7A, 7B, 8A~ 8B~ 9A, 9Bo lOA, 31 lOB and 11 are flow charts depicting how the various signals are 32 handled by the control circuit microprocessor.
33 Turning now to Figures 1, 2 and 3, a tractor ~ for 34 carrying the apparatus is shown in a field 2, and has a spray bar 3 attached and extending outwardly on both sides thereof. Spray 36 heads or nozzles 4 are located at regular intervals along the 37 spray bar, for spraying the field with a fluid carried by the 38 tractor in a tank (not shown). The spray regions 5 extending 39 from the spray heads or nozzles define a broad line ~rom one end L~k 5 02 oE the bar at one side of the tractor to -the other end. As the 03 -tractor progresses down the field, an area is sprayed defined by 04 the sum of the spray regions (total width) multiplied by the 05 dis-tance travelled by the tractor.
06 A control 6 is located within the cab of the tractor 07 1. The control 6 includes an alphanumeric display 7, a selector 08 switch 8 and a "set" pushbutton 9.
09 Inputs to -the control unit 6 are carried via cab].es extending outside the cab of -the tractor, and are comprised of a 11 speed sensor 10 and a fluid flow sensor 11.
12 The speed sensor 10 is comprised of a metal detector 13 12, for detecting a one or more metal discontinuities 13 on the 14 wheel 14 of the tractor. A discontinuity which is sensed can be, alternatively, on any rotating or reciprocating member of the 16 tractor which has its rate of rotation or reciprocation a 17 function of the speed of the tractor. The function is determined 18 by field calibration of the present invention as will be 19 described later. Metal detector 12 outputs a pulse each time the aforenoted discontinuity passes across it. In case more than one 21 discontinuity is to be detected, the output pulse rate will be 22 higher, but field calibration will take care the pulse rate 23 interpretations. The speed sensor can also be a photoelectric or 24 other type of sensor.
The flow sensor 11 is also of the type which provides a 26 series of output pulses, the number of pulses in a given time 27 being determined by the rate of fluid flow. Preferably the form 28 of flow sensor which is used is of the type described in Canadian 29 Patent Application Serial No. 344,891 filed February 1, 1980 entitled FLOW RATE SENSOR, invented by Simon OKKERSE and 31 Hugh C. WOOD. In this form of flow sensor, a non-magnetic 32 turbine is inserted into the fluid flow line 15, t~e flow line 33 carrying the fluid to be sprayed between a tank 6 and the spray 34 heads 4 via a pump 17. The turbine rotates with flo~ of the fluid to be sprayed, and metallic elements in each paddle of the 36 turbine are dete~ted as they pass by a metal detector. The metal 37 detector is comprised of a coil of wire carrying a.c. current;
38 the presence of metal in each paddle modulates the current which 3 ~ 7~ X
02 is then detected, converted to a pulse waveform, and is carried 03 to -the control unit 6.
04 Accordingly pulses are applied to the control unit via 05 two separate conductive lines, one carrying pulses at a rate 06 which is a function of speed of the tractor, and the other 07 carrying pulses at a rate which is a Eunction of the ~low rate of 08 the fluid in the fluid flow line (which is the volume oE fluid 09 per unit time which is sprayed).
The "set" button 9 is used to input data signals to the 11 control unit 6 for calibration purposes. Its operation will be 12 described below.
13 The selector switch 8 has a number of positions as 14 follows: Width, Cal, Pumped, Spray Rate, Speed, Area, Area/Hour, and Distance.
16 In order to calibrate the speed sensor, the ollowiny 17 functions are performed. It should be noted that -this 18 calibration determines the Eunctional relationship of the pulse 19 rate to the actual vehicle speed, and compensates Eor wheel size, tire pressure, softness of the field and other characteristics of 21 the pulse repetition.
22 Two stakes are driven into the ~ield which is to be 23 worked, e.g.e~actly 150 feet apart (in the preferred 24 embodiment). The selector switch 8 is placed in the "cal"
position. The tractor is driven past the first stake to the 26 second, at a constant speed, such as 3-5 miles per hour. As the 27 tractor is driven up to the first stake, the "set" button is 28 pressed. As soon as the ~irst stake is passed, the "set" button 29 is released. The control unit 6 applies counting signals to the display 7, which begins displayiny sequentially increasing digits 31 as the wheel tar~ets (metal discontinuities) 13 pass the metal 32 detector 12. As the second stake is passed, the set button 33 should be pressed and released quickly. This is detected by 3~ control unit 6, which stops the counting on the display.
The control unit 6 stores the signal on the display, 36 which is determined at e~actly 150 feet. This calibration number 37 is automatically entered into the memory of the control unit, and 38 is used for distance and speed determination.
39 Accordingly, the calibration constant stored is the ~,3,,3, t~ r 02 number of pulses obtained from the metal detector 12 within a 03 prede-termined distance (150 fee-t in -this embodiment) bu-t can be 04 automatically determined to a different base line distance (e.g.
05 l00 feet) by dividing the signals down. In the event that tire 06 pressure was low, there will be a greater number o~ pulses 07 between the stakes than if the tire pressure was higher. This 08 clearly distinguishes between the above-described prior art 09 devices which merely count the number of pulses of a rotating member, and assume that the number of pulses corresponds to a 11 given distance. Clearly a more accurate distance determ:ination 12 is facilitated using the present inven-tion.
13 The calibration constant, which appears on the display, 14 can be written down for future input when using the same lS equipment in the same field, assuming that the tire pressure is 16 the same. This can be applied by selecting the "Cal" inpu-t Y
17 position, and pressing the set button until the same number is 18 obtained as in the field calibration.
19 Typically, if the loaded tire radius is 11-1/4 inches, and four targets or discontinuities are on the wheel for 21 detection by metal detector 12, the calibration constant on the 22 display will be about 815. It has been found that different 23 calibration values will be obtained from soft and hard ground, 24 from field conditions to road conditions, and with different tire pressures. That these calibrations are considerably different 26 illustrates the improvement in accuracy obtained with the present 27 invention from prior art structures.
28 The spray width should be set into the control unit 6.
29 The selector 8 is turned to the "Width" position, and the set button 9 is depressed and held. The display 7 begins increasing 31 from zero toward the required width. At the required width, the 32 set button is released. In case the correct width value has been 33 overshot, the set button is depressed again, and the count begins 34 decreasing. As soon as the correct width is located, the set button is released. Depression of the set button again increases 36 the count. In this manner the procedure can be repeated until 37 the proper value is obtained. This value is stored in tha 3B control unit memory.
39 The number on the display can of course be in decimal 1 ~l ti 7 ~
02 feet, or, if the apparatus is calibrated or swltchable to a 03 metric scale, the width would be in decimal meters.
04 The flow sensor 11 can now be calibrated. The selector 05 switch should be switched to the Area/Hour position, and the set 06 button depressed for about one second. The set button should 07 then be released and pressed again, and held until -the value 10.0 08 is displayed. The value can of course can be increased or 09 decreased as described above with respect to calibra-tion of the spray width.
11 The selector switch is then placed in the Pumped 12 posi-tion, and the set button is pressed -to enter zeros.
13 The tank is then filled and pumped out at the flow rate 14 intended to be used in the actual spraying, the selector switch being moved to Spray Rate. When the tank is empty, the selector 16 switch 8 should be placed in the Pumped position, and the 17 displayed value should be compared with the measured quantity of 18 liquid actually pumped.
19 The new calibration constant is 10.0 x value displayed on the monitor divided by the actual volume pumped.
21 The new calibration constant should then be entered 22 into the control unit in the Area/Hour position, replacing the 23 value 10.0 with the new calibration constant.
~3 parti~ularly to a Inonitor ~or a ~ s~rayer, ~UC~I as a ~n~mical 04 spra~er.
05 The spray application of chemicals such a~ ~r-t~ rs, 06 pesticides, etc., to the field requires careful con-trol, in order 07 to optimize the rate of applicàtion. This is desirable bo-th to 08 minimize cost and to apply the reco~lmended concentration.
09 The sprayer operator normally calculates the rate oE
application of the chemical to be sprayed by establishing a flow 11 rate from his mobile storage tank to the spray nozzles, measuring 12 the width of the spray, and establishing a certain rate of speed 13 of the spray vehicle. The field area covered within a given time 14 period allows him to calculate the volume of fluid per unit area which ha~ been applied (e.g. gallons per acre).
16 While the application rate, with a given vehicle speed, 17 can be calculated before spraying, should the flow rate change 18 during spraying due to a build up of residue in the fluid pipes, 19 should a change in vehicle speed be desired, etc., it would be a difficult and tedious task to maintain a continuous calculation 21 effort in the field, which would be re~uired to ensure that the 22 required application rate is maintained. Consequently apparatus 23 has been made available to the sprayer operator which performs 24 the calculation automatically and provides an indication of certain parameters to him, such as the area covered, the number 26 of gallons per acre applied, etc. In such prior art apparatus 27 flow of the spray fluid is measured as well as the vehicle speed, 28 and knowing the spray width which is utilized, charts or other 29 indicators provide an output indication.
In one such prior art device, in order to measure 31 vehicle speed an electromagnetic detector is used to detect 32 a metallic discontinuity or a magnet applied to a vehicle wheel.
33 The rotation rate of the wheel is converted by the apparatus into 34 vehicle speed. Calibration for the wheel circumference is done by thumb~wheel switch. A water flowmeter provides an electrical 36 signal which is alleged to be proportional to the amount of fluid 37 flowing to the spray heads. This apparatus calculates applied 38 gallons per acre.
39 In another such device, a photosensor is used to ~, ' 02 sense markings on the vehicle wheel, to determine i-ts ro-tation 03 rate and thus the speed of the vehicle. Alternatively, an 04 outboard wheel which Eo:Llows the vehicle is used to determine the 05 ground speed. This apparatus also :includes means to synchronize 06 the spray bar pressure with ground .speed via a servo control 07 valve.
08 The sprayer monitors utilizing the above-noted vehicle 09 speed sensors all have a deficiency in common, that is, that the rate of application data given to the farmer is determined by a 11 parameter which is not an accurate representation of the 12 parameter purported to be represented. E'or example ground speed 13 is determined by -the rotation rate oE a wheel or the rotation 14 rate of a shaft. Where the ground is soEt or the tire inflation pressure of the tractor or vehicle wheel is low, the vehicle 16 wheel will rotate a greater number of times for a given linear ~7 distance than if the inflation pressure were higher or the ground 18 firmer. The chemical flow rate per unit time might then be 19 increased, resulting in wasteage of spray fluid.
Where an outboard wheel is used, mud and debris can 21 impede its smooth operation, and it can be subject to bounce, 22 thus reducing its accuracy.
23 The present invention, on the other hand, allows the 24 sprayer operator to calibrate his vehicle and spray apparatus directly, the calibration constants being stored by the 26 apparatus, thus giving him a substantially improved accuracy of 27 spray application.
28 The present invention provides the sprayer operator 29 with an accurate measurement of the rate of fluid application, the total volume applied, the true ground speed, the area 31 covered, the spray rate, and the distance travelled. Calibration 32 is controlled at the vehicle driver's seat.
33 In the present invention the ground speed sensor is a 34 metal detector which detects metal targets or discontinuities on a wheel or on any rotating part which has its speed related to 36 ground speed. A circuit determines the distance travelled as 37 each target passes and the ground speed is computed. Means is 38 further provided to calibrate the ground speed, with tire size, 39 tire pressure and soil compaction effects automatically accounted , 7~.a,~
0]. 3 02 and compensated for, resulting in a more accura-te representation 03 of the ground speed than in the prior art.
04 The fluid flow rate is determined by a flowmeter in the 05 Eluid flow line leading to -the spray bar carrying the spray 06 heads. A pulsing signal sent from the flowmeter is proportional 07 to the volume pumped per unit time. The width of the spray line 08 is entered into the apparatus by pu!~hbutton. A digital display 09 provides the output to the operator.
Clearly the application rate is de-termined by how fast 11 an area is covered and by the quant:ity of chemical sprayed. The 12 present invention multiplies signal represen-ting the speed and 13 width, and the result is divided into the flow rate to obtain the 14 rate of application of the fluid. All other outputs provided to the operator are obtained from the three measurements noted 16 above, of speed, flow rate and width. Since the width can be 17 determined by actual measurement, and is normally relatively 18 stable, and both flow rate and speed are calibrated by actual 19 tests or by manually input-ting constants relating to particular fields, for example, the present apparatus has been found to have 21 considerably improved accuracy over prior art apparatus.
22 The invention, in general, is a sprayer monitor for 23 spray vehicles comprising a sensor for sensing the speed of 24 the sprayer and for providing a first signal representative of the speed, a sensor for sensing the rate of flow of a ~luid to be 26 sprayed and for providing a second signal representative of the 27 rate of flow, a memory for storing a third signal representative 28 of the width of the sprayer, a display, and a control circuit for 29 receiving the signals and for generating a display operating signal and applying it to the display, which corresponds to the 31 value of the second signal divided by the product of the first 32 and third signals, representing the volume of fluid sprayed per 33 unit area.
34 More particularly, the invention is a sprayer monitor for a spray vehicle comprising: a circuit for receiving a speed 36 indication signal comprising a plurality of pulses, the frequency 37 of the pulses being related by a predetermined speed factor 38 signal to the actual speed of the vehicle, a circuit for 39 receiving a fluid flow indication signal comprising a plurality ~ `
7 ~1 ~A r j 02 o pulses, the frequency oE the pulses being related by a 03 predetermined flow factor signal to the actual spray fluid flow 04 rate, a memory for storing signals represen-tative of the spray 05 width of the sprayer, and said speed and flow factor signals, a 06 display, and a control circuit connected to the display, the 07 receiving circuit and the memory Eor generating a signal 08 representing a number of speed indication pulses received in a 09 predetermined time and a further signal representing a number of fluid flow indication pulses received in a predetermined time, 11 and for applying the speed factor signal to the signal 12 representing the number of speed indication pulses received in a 13 predetermined time to obtain an actual speed signal, and for 14 applying the flow factor signal to the signal representing the number of fluid flow indication pulses received in a 16 predetermined time to obtain an actual fluid flow rate signal, 17 for multiplying the speed signal and the width signal and for 18 dividing the result into the fluid flow rate signal to obtain a 19 signal representative of -the volume of fluid applied per unit area, and for applying the latter signal to the display.
21 A better understanding of the invention will be 22 obtained by reference to the description of the preferred 23 embodiment of the invention described in detail below and to the 24 following drawings, in which:
Figure 1 is a general view of a tractor with a spray 26 bar attachment with which the present invention is used, 27 Figure 2 is a general pictorial view of the invention, 28 Figure 3 is a general block diagram of the invention, 29 Figure 4 is a logic schematic of the invention, and Figures 5A, 5B, 6A, 6B, 7A, 7B, 8A~ 8B~ 9A, 9Bo lOA, 31 lOB and 11 are flow charts depicting how the various signals are 32 handled by the control circuit microprocessor.
33 Turning now to Figures 1, 2 and 3, a tractor ~ for 34 carrying the apparatus is shown in a field 2, and has a spray bar 3 attached and extending outwardly on both sides thereof. Spray 36 heads or nozzles 4 are located at regular intervals along the 37 spray bar, for spraying the field with a fluid carried by the 38 tractor in a tank (not shown). The spray regions 5 extending 39 from the spray heads or nozzles define a broad line ~rom one end L~k 5 02 oE the bar at one side of the tractor to -the other end. As the 03 -tractor progresses down the field, an area is sprayed defined by 04 the sum of the spray regions (total width) multiplied by the 05 dis-tance travelled by the tractor.
06 A control 6 is located within the cab of the tractor 07 1. The control 6 includes an alphanumeric display 7, a selector 08 switch 8 and a "set" pushbutton 9.
09 Inputs to -the control unit 6 are carried via cab].es extending outside the cab of -the tractor, and are comprised of a 11 speed sensor 10 and a fluid flow sensor 11.
12 The speed sensor 10 is comprised of a metal detector 13 12, for detecting a one or more metal discontinuities 13 on the 14 wheel 14 of the tractor. A discontinuity which is sensed can be, alternatively, on any rotating or reciprocating member of the 16 tractor which has its rate of rotation or reciprocation a 17 function of the speed of the tractor. The function is determined 18 by field calibration of the present invention as will be 19 described later. Metal detector 12 outputs a pulse each time the aforenoted discontinuity passes across it. In case more than one 21 discontinuity is to be detected, the output pulse rate will be 22 higher, but field calibration will take care the pulse rate 23 interpretations. The speed sensor can also be a photoelectric or 24 other type of sensor.
The flow sensor 11 is also of the type which provides a 26 series of output pulses, the number of pulses in a given time 27 being determined by the rate of fluid flow. Preferably the form 28 of flow sensor which is used is of the type described in Canadian 29 Patent Application Serial No. 344,891 filed February 1, 1980 entitled FLOW RATE SENSOR, invented by Simon OKKERSE and 31 Hugh C. WOOD. In this form of flow sensor, a non-magnetic 32 turbine is inserted into the fluid flow line 15, t~e flow line 33 carrying the fluid to be sprayed between a tank 6 and the spray 34 heads 4 via a pump 17. The turbine rotates with flo~ of the fluid to be sprayed, and metallic elements in each paddle of the 36 turbine are dete~ted as they pass by a metal detector. The metal 37 detector is comprised of a coil of wire carrying a.c. current;
38 the presence of metal in each paddle modulates the current which 3 ~ 7~ X
02 is then detected, converted to a pulse waveform, and is carried 03 to -the control unit 6.
04 Accordingly pulses are applied to the control unit via 05 two separate conductive lines, one carrying pulses at a rate 06 which is a function of speed of the tractor, and the other 07 carrying pulses at a rate which is a Eunction of the ~low rate of 08 the fluid in the fluid flow line (which is the volume oE fluid 09 per unit time which is sprayed).
The "set" button 9 is used to input data signals to the 11 control unit 6 for calibration purposes. Its operation will be 12 described below.
13 The selector switch 8 has a number of positions as 14 follows: Width, Cal, Pumped, Spray Rate, Speed, Area, Area/Hour, and Distance.
16 In order to calibrate the speed sensor, the ollowiny 17 functions are performed. It should be noted that -this 18 calibration determines the Eunctional relationship of the pulse 19 rate to the actual vehicle speed, and compensates Eor wheel size, tire pressure, softness of the field and other characteristics of 21 the pulse repetition.
22 Two stakes are driven into the ~ield which is to be 23 worked, e.g.e~actly 150 feet apart (in the preferred 24 embodiment). The selector switch 8 is placed in the "cal"
position. The tractor is driven past the first stake to the 26 second, at a constant speed, such as 3-5 miles per hour. As the 27 tractor is driven up to the first stake, the "set" button is 28 pressed. As soon as the ~irst stake is passed, the "set" button 29 is released. The control unit 6 applies counting signals to the display 7, which begins displayiny sequentially increasing digits 31 as the wheel tar~ets (metal discontinuities) 13 pass the metal 32 detector 12. As the second stake is passed, the set button 33 should be pressed and released quickly. This is detected by 3~ control unit 6, which stops the counting on the display.
The control unit 6 stores the signal on the display, 36 which is determined at e~actly 150 feet. This calibration number 37 is automatically entered into the memory of the control unit, and 38 is used for distance and speed determination.
39 Accordingly, the calibration constant stored is the ~,3,,3, t~ r 02 number of pulses obtained from the metal detector 12 within a 03 prede-termined distance (150 fee-t in -this embodiment) bu-t can be 04 automatically determined to a different base line distance (e.g.
05 l00 feet) by dividing the signals down. In the event that tire 06 pressure was low, there will be a greater number o~ pulses 07 between the stakes than if the tire pressure was higher. This 08 clearly distinguishes between the above-described prior art 09 devices which merely count the number of pulses of a rotating member, and assume that the number of pulses corresponds to a 11 given distance. Clearly a more accurate distance determ:ination 12 is facilitated using the present inven-tion.
13 The calibration constant, which appears on the display, 14 can be written down for future input when using the same lS equipment in the same field, assuming that the tire pressure is 16 the same. This can be applied by selecting the "Cal" inpu-t Y
17 position, and pressing the set button until the same number is 18 obtained as in the field calibration.
19 Typically, if the loaded tire radius is 11-1/4 inches, and four targets or discontinuities are on the wheel for 21 detection by metal detector 12, the calibration constant on the 22 display will be about 815. It has been found that different 23 calibration values will be obtained from soft and hard ground, 24 from field conditions to road conditions, and with different tire pressures. That these calibrations are considerably different 26 illustrates the improvement in accuracy obtained with the present 27 invention from prior art structures.
28 The spray width should be set into the control unit 6.
29 The selector 8 is turned to the "Width" position, and the set button 9 is depressed and held. The display 7 begins increasing 31 from zero toward the required width. At the required width, the 32 set button is released. In case the correct width value has been 33 overshot, the set button is depressed again, and the count begins 34 decreasing. As soon as the correct width is located, the set button is released. Depression of the set button again increases 36 the count. In this manner the procedure can be repeated until 37 the proper value is obtained. This value is stored in tha 3B control unit memory.
39 The number on the display can of course be in decimal 1 ~l ti 7 ~
02 feet, or, if the apparatus is calibrated or swltchable to a 03 metric scale, the width would be in decimal meters.
04 The flow sensor 11 can now be calibrated. The selector 05 switch should be switched to the Area/Hour position, and the set 06 button depressed for about one second. The set button should 07 then be released and pressed again, and held until -the value 10.0 08 is displayed. The value can of course can be increased or 09 decreased as described above with respect to calibra-tion of the spray width.
11 The selector switch is then placed in the Pumped 12 posi-tion, and the set button is pressed -to enter zeros.
13 The tank is then filled and pumped out at the flow rate 14 intended to be used in the actual spraying, the selector switch being moved to Spray Rate. When the tank is empty, the selector 16 switch 8 should be placed in the Pumped position, and the 17 displayed value should be compared with the measured quantity of 18 liquid actually pumped.
19 The new calibration constant is 10.0 x value displayed on the monitor divided by the actual volume pumped.
21 The new calibration constant should then be entered 22 into the control unit in the Area/Hour position, replacing the 23 value 10.0 with the new calibration constant.
2~ The amount of ~luid which is actually pumped and the actual ground speed can thus be accurately calibrated in the 26 present invention, and affords substantial advantages over prior 27 art devices, particularly when the fluid has unusual viscosity 28 (e.g. liquid mixed with seed), is applied with changing pump 29 rates, must be used with changing field conditions, tire pressures, etc. Where the apparatus has been calibrated for 31 different portions of a field which exhibits widely varying ~but 32 predetermined) field conditions, the apparatus can be quickly 33 manually recalibrated, and provide an accurate representation of 34 the parameters.
With the selector switched into the Pumped position, 36 the total volume of liquid which has passed through the ~low 37 meter is displayed. Each time a unit (i.e.gallon or liter) of 38 the chemical passes through the flow meter, the display increases 39 by one and a decimal similar unit. With the selector switch in , 02 the Spray Rate position, the application rate for the chemical in 03 e.g. gallons per acre is displayed. With the selector swi-tch set 04 to Speed, the true ground speed in e.g. tenths of miles per hour 05 is displayed.
06 When the sprayer is operated, the total area worked is 07 continuously added up. When the selector s~itch is set to Area, 08 the total area worked, e.g. in acres is displayed. When the 09 chemical fluid stops flowing, and the flow meter stops sending pulses, and the in the control unit accumulation of the sum of 11 the acres sprayed, is automatically shut off.
12 With the selector switch set to Area/Hour, the true 13 current ra-te of working the field is displayed, e.g. in acres per 14 hour. ~ith the selector switch is set to Distance, the display shows the distance in feet that the implement has moved.
16 Of course the control unit 6 can be calibrated in 17 either imperial or metric units; conversion constants to km/hour 18 for speed, litres per hectare for spray rate, hectares for area, 19 etc., can be stored in the apparatus. Indeed, an external switch for switching between the imperial and metric forms of 21 measurement can be utilized (not shown).
22 Turning now to Figure 4, a schematic of the invention 23 is shown.
24 The speed pickup described earlier, comprised of a metal detector, includes a coil 20 mounted adjacent a metal 26 extension or discontinuity on a wheel or rotating member of the 27 tractor, the rotation rate (or reciprocation rate) of which is 28 related to its assumed speed. The coil 20 is connected via a 29 shielded cable 21 to the control unit.
In the control unit, an oscillator 22 applies a signal~
31 such as at a 20 kilohertz frequency, to coil 20. The coil 20 32 carries the signal, and when a metal discontinuity passes in the 33 field, modulates the signal. The resulting modulated signal is 34 A.C. coupled via capacitor 23 to detector diodes 24. Noise spikes or the like are bypassed to ground via capacitor 25.
36 Following detection in diodes 24, the detected 37 modulation signal is A.C. coupled via capacitor 26 (after being 38 lowpass filtered by capacitor 27 in parallel with resistor 28 39 bypassing the signal-carrying circuit to ground), is applied via ~ .~ t; ,r~
02 resistor 29 to one input of comparator 30. The other input of 03 comparator 30 is connected to the tap of a resistive voltage 04 divider comprising resistors 31 and 32 connected between a source 05 of potential +V and ground. Pulse signals detected ~rom -the 06 modulated oscillator signal, which modulation was cau~ed by 07 discontinuities detected in coil 20, have their amplitudes 08 cornpared with a threshold voltage in order to avoid operation of 09 the following circuitry by noise pulses. The resulting output signal from comparator 30 is applied to the clock input of f:lip 11 flop 33. The gain of comparator 3C) is controlled by resistor 34, 12 which is connected from the Eirst-noted input of comparator 30 to 13 the junction between the two resistors 35 and 36 which are 14 connected in series between the output of comparator 30 and ground.
16 The output signal at output Q of flip flop 33 is a 17 square wave, with the number of pulses per minute being a 18 function of the vehicle speed.
19 The flow of fluid to be sprayed is detected in flow sensor 37, which produces output pulses at a rate which is a 21 function of the rate of fluid flow to the vehicle spray nozzles.
22 The flow sensor can be the type described earlier, i.e. the type 23 described in the aforenoted copending patent application, or 24 some other flow sensor which provides a pulse signal which has a rate which is a function of the flow rate of the fluid which is 26 measured . Its output signal is applied to inverting buffer 38 27 (its input also being connected to ground via a line-impedance 28 determining resistor 39~, and its output is connected to the 29 clock C input of flip flop 40. The output signal at the Q output of flip flop 40 thus is a series of pulses having a rate which is 31 a function of the flow rate of the fluid passing to the vehicle 32 spray nozzles.
33 It should be noted that the pulses applied to flip 34 flops 33 and 40 are inverted. Thus at the rising trailing edge of each of the pulses, the flip flops are clocked, and the Q
36 output goes hi~h.
37 The output signal of flop flop 33 is applied to one 38 input of NOR gate 41, and also to -the input of a tristate buffer 39 42. The output of tristate buffer 42 is connected to one lead of ,~, 02 data bus 43.
03 The output signal of flip flop 40 is connected -to the 04 second input of ~OR gate 41, and a]so to the input of tristate 05 gate 44, the output of which is connected to a another lead of 06 data bus 43.
07 With pulses being received from the vehicle speed 08 sensor or flowsensor 37, output pul3es are applied to NOR yate 09 41, which generates an output pulse signal which is applied to the interrupt input INT of a microprocessor 45. The data bu~ 43 11 is of course connected to microprocessor 45, as is an address bus 12 46, a control bu~, etc., in a manner well known to those skilled 13 in the art. Memory 47 is also connected to microprocessor 45 via 14 the bus system.
Microprocessor 45 is also connected to a plurality of 16 decoder/drivers 48a, 48b and 48c, the outputs of which are 17 connected to corresponding alphanumeric display elements 49a, 49b 18 and 49c. The connections are shown as buses, but of course the 19 outputs of the decoder/drivers are connected to the display element terminals via resistors, a representative resistor 50 21 being shown.
22 Microprocessor 45 has a plurality of outputs P20-P23 23 which are connected to inputs of a a decoder 51. An output ~6 of 24 decoder 51 is connected to the base of NPN transistor 52, the collector of which is connected to the decimal point input 53 of 26 display element 49b.
27 The timing reset input To of microprocessor 45 is 28 connected to ground via SET pushbut-ton 54 (which corresponds to 29 switch 9, Figs. 2 and 3), and also to a source of potential ~V
via resistor 55.
31 It is preferred (but not mandatory) that the 32 microprocessor and ancillary memories, etc., should be the 8000 33 family type available from Intel Corporation, such as 8035L, 34 8039/8048, 8049. A full description of the structure, operation and manner of programming this microprocessor is available in 36 many microcomputer manuals, such as MICROCOMPUTER PRIMER, by M.
37 Waite and M. Pardee, published by Howard W. Sams and Company, 38 Inc., 1976, and from Intel Corporation. A detailed description 39 thereof is therefore believed to be within the skill of a person s 02 skilled in the art, and since a detailed description thereof 03 would be redundant and unnecessary, it will not be repeated here.
04 Returning now to decoder 51, a further output Ql is 05 connected via resistor 56 to -the base of NPN transistor 57. The 06 collector of transistor 57 is connected to an alarm terminal, its 07 emitter being connected to ground. The alarm can be used to 08 alert the operator if the spray rate is being measured by no 09 pulses are being received Erom the flow sensor, for example.
An output Q3 of decoder 51 is connected via an 11 inverting buffer 58 to a controlled output -terminal, which has a 12 return lead to ground. This terminal can be used for switching 13 on -the spray pump, for example.
14 Another output Q4 of decoder 51 is connected to the reset inputs R of flip flops 33 and 40.
16 A clock source, preferably comprising a 3.579 megahertz 17 crystal oscillator (not shown) is connected in a conventional 18 manner to microprocessor 45. An internal clock divider in the 19 microprocessor applies a signal at 1/15th this rate to its ALE
output, which signal is applied to the clock input C of decoder 21 51, and also to the memory address decoders (not shown). The ALE
22 output is also connected to the clock input of a 1/4 divider 59, 23 the output of which is connected to a Tl counter input of 24 microprocessor 45.
The selector switch 8 is connected between a source of 26 potential ~V to one out of 8 inputs D0-D7 o~ a priority encoder 27 60. Each of the inputs D0-D7 is connected via a resistor 61a, 28 61b,... 61h to ground. Thus ground potential is applied via one 29 of resistors 61a-61b to each of the inputs D0-D7 unless switch 8 is switched to one of the inputs. Potential +V is appliea to the 31 encoder input to which switch 8 is connected.
32 The switch positions are preferably allocated and 33 labelled as shown: WIDTH, CAL, PUMPED, SPRAY RATE~ SPEED, AREA, 34 AREA/HOUR, and DISTANCE.
The outputs Q0-Q2 of encoder 60 are connected via 36 tristate gates 61, 62 and 63 to various leads of data bus 43.
37 A further tristate gate 64 has its input connected to 38 manual switch 66, which is connected from source of potential ~V
39 via resistor 65 to ground. The output oE tristate gate 64 is ' 1 s 02 connected to one of the leads oE data bus 43. The input of 03 gate 64 is at high potential unless switch 66 is closed, which 04 forces the input of gate 64 to low potential. Switch 66 is used 05 as an enabling input for metric or imperial conversion in 06 microprocessor 45.
07 All of the enable inputs of tristate gates 42, 44, 09 and 61-64 are connected together, and to the read RD output of microprocessor 45. The signals applied to the gates are thus 12 read when the RD output goes high.
13 The microprocessor multiplies signals representing the 14 speed of the vehicle and the spray width, and divides khe result into a signal representing the fluid flow rate to obtain the rate 16 of application to the fluid. Assuming that a signal representing 17 the spray width has been stored in the microprocessor memory 18 using the set switch 54, signals representing the speed and flow 19 rate must be received.
As noted earlier, pulses at a rate representative of 21 the vehicle speed are output from flip flop 33 and are applied to 22 one input of NOR ga-te 41 and to tristate gate 42 and pulses at a 23 rate representative of the flow of ~luid are output from flip 24 flop 40 to the second input of NOR gate 41, and to the input of tristate gate 44. With the input of a pulse from either of flip 26 flops 33 or 40, an interrupt signal is generated to 27 microprocessor 45.
28 Microprocessor 45 in response generates a read signal on the RD output, enabling all of tristate gates 42, 44, and 31 61-64.
32 Assuming that the spray rate is to be displayed, switch 33 8 had been positioned so that input D4 of encoder 60 is connected 34 to potential source ~V. The resulting encoded output signal of encoder 60 is thus applied to data bus 43 ~ia tristate gates 61, 37 62 and 63, when the read enable signal on the RD lead is 38 received. The microprocessor is thus informed that the program 39 for displaying the spray rate should be accessed.
At the same time, the pulse applied to one of the two 41 inputs of tristate gates 42 and 44 is applied to data bus 43. It 03 should be noted that a signal on the microprocessor RD output 04 will not occur if pulses are present at the output of flip flops 05 33 and 40 simultaneously, since NOR gate 41 will be inhibited;
06 the microprocessor would be confused as to which source count to 07 increment.
08 In the case of a single input pulse to NOR gate 41, an 09 output signal from only one of tristate gates 42 and 44 will be present, and is input via data bus ~L3 to microprocessor 45.
11 Having determined which lead of data bus 43 carries the input 12 pulse signal, the microprocessor est:ablishes whether the pulse is 13 a speed pulse or a flow rate pulse.
14 It was noted earlier that a signal appears on the ~LE
lead of microprocessor 45 which is 1/15th the rate oE -the cr~stal 16 oscillator, i.e. 1/15th of 3.579 megahertz. This reduced clock 17 rate is further reduced in a 1/4 divider 59, the output of which 18 is applied to input Tl of microprocessor 45, i.e., at 59,650 19 pulses per second. This further reduced rate is counted with internal counters in microprocessor 45.
21 When an interrupt arrives from the output o~ NOR gate 22 41, the internal clock count of the count from input Tl is 23 recorded. The successive clock pulse counts are also 24 subtracted, to obtain rate variations.
Assuming that in lS0 feet there are 185 speed 26 interruptions, i.e. 5.4 interruptions per second, the internal 27 clock counts about 11,000 pulses on the Tl input between speed 28 pulses. This value is internally converted to a speed rate, the 29 signals being decoded in decoder drivers 48a, 48b and 48c and are applied to display segments 49a, 4gb and 49c when the selector 31 switch 8 is switched to the D3 input of decoder 60.
32 Pulses from the flow sensor 37 occur at a much faster 33 rate, typically between 10 pulses per second and 5,000 pulses per 34 second. Microprocessor 45 recognizes the source of pulses as described above, using the count reached of the pulses on lead Tl 36 to establish the spped and flow rate value signals used in the 37 aforenoted calculation.
38 When the microprocessor determines which source, either 39 the speed or flow sensor from which the input pulses are being received, it outputs a signal to decoder 51, which applies a 02 signal to output Q4, which resets both Elip flops 33 and 40. The 03 next pu]se which is received by those flip flops thus outputs on 04 their Q outputs.
05 The microprocessor is caused to accept and store the 06 spray width calibration when switch 8 is connected to input D7 of 07 encoder 60. An encoded output signal from tristate gates 61-63 08 is applied to data bus 43, which causes the microprocessor to 09 accept count input signals on lead Tl, when pushbutton 54 is closed, applying an enable signal to input T0. The count signal 11 is displayed on display elements 49a, 49b and 49c. Successive 12 closures o~ switch 54 cause -the count swn in microprocessor 45 13 successively to increase or decrease, the result being 14 automatically stored in a memory location allocated to the width parameter.
16 When the switch 8 is set to input D6 of encocler 60, the 17 microprocessor is caused to receive input pulses from the speed 18 coil 20 via flip flop 33 and store the resulting count, as long 19 as the set pushbutton 54 is open. There~ore when calibrating the apparatus, the set pushbutton 54 is closed as the vehicle is 21 driven past a first calibration post, and immediately released.
22 As soon as the set pushbutton is open, pulses from flip flop 33 23 are applied via data bus 43 to the microprocessor, and are 24 counted, and a count displayed on display 53~ As soon as the second calibration post is reached, the set 54 pushbutton is 26 momentarily depressed, and the sum of the counts is retained in 27 memory as the speed calibration factor.
28 When switch 8 is switched to contact the D5 input of 29 encoder 60, the circuit operates similarly, except that pulses from the flow sensor 37 and flip flop 40 are accepted.
31 Switch 8 being closed to inputs D4, D3, D2, Dl or D0 of 32 encoder 60, enables the microprocessor 45 to display the spray 33 rate, speed, area, area per hour, and distance respectively on 34 display elements 49a, 49b and 49c.
A preferred algorithm for the firmware used to operate 36 the microprocessor is described below, with reference to Figures 37 5A-ll. Of course other algorithms may be designed. The 38 parameters referred to are of course names of corresponding 39 signals. Figures 5A and 5B are a flow chart of the signal logic ~ j 02 in the microprocessor for computing and displaying and 03 calibra-ting the flow rate (area per hour), and is described 04 below. This is a subroutine of a master flow chart, and is 05 described first for the purpose of better illustrating the 06 invention. These figures are intended to form an appendix to the 07 specification, rather than ~orming illustrating figures of the 08 structure of the invention.
09 It was noted earlier that -the bit rate input to input Tl of microprocessor 45 is 59,659 PPS. A signal representing 11 this number, representing the period between successive timer 12 pulses, is multiplied in a first step by the count oE the flow 13 rate pulses between interrupts.
14 Thus the accumulated flow time between the last (R3) and present (R4) interrupts is accumulated as the value 16 FLACHI,LO, which is stored in memory locations TEMP2 and Rl.
17 In the next step, the accumulated flow pulse count is 18 divided by the accumulated actual time since the last calculation 19 (counting pulses). This gives the number of pulses per second.
In order to determine the number of gallons per minute, 21 the flow rate A offset at which the flow meter star-ts to ro-tate 22 (a constant) is added to the slope of the linear characteristic 23 curve of the flow rate sensor (Bx). Bx is determined 24 experimentally, and for the flow rate sensor described in the aforenoted patent application, is the frequency x 256.
26 Accordingly in this calculation the number of pulses per second 27 is converted into a flow rate in gallons per minute, the 28 correlation having been determined experimentally. This value is 29 stored in memory locations R6 and R5.
This flow rate is multiplied by a number, the number 31 900 being used as a first approximation, and divided by a flow 32 calibration value FLOCAL, which is entered by the operator. The 33 result is stored as a flow rate value EXFLOW.
34 The flow rate EXFLOW is multiplied by FLACHI or FLACHO, and divided by a constant (546) to convert the values to gallons 36 (or a different constant to convert the value to litres).
37 This results in the value DPUMPED, a charge in the 38 amount pumpad, being stored at R6 and R5.
39 DPUMPED is then added to GALLLO, or GALLHI (gallons low 02 or gallons high), the carry bit being then propagated through the 03 value PUMPED, the amount of spray which has been pumped. Pumped 04 is then updated by the change in the amound pumped DPUMPED.
05 If the speed of the vehicle is 0, the time flow rate 06 per unit time is displayed alternatively with a code indicating 07 that it is a timed flow rate rather than an area flow rate, e.g., 08 an audible alarm is activated as dec;cribed earlier.
09 If the speed of the vehic]e is not 0, the alarm bit is deactivated, FLOW RA'rE is reloaded, multiplied by 600 ~converting 11 it into 10ths of a gallon per acre), the resulting vaLue is 12 divided by acres per hour, resulting in a spray rate value, 13 stored at R6 and R5.
14 The signal is then applied through a low pass filter to remove ripple, i.e., a time average is implemented over two to 16 three seconds, rather than to 100 milliseconds. The area sprayed 17 per hour is then displayed.
1~ Turning to Figure 5B, the spray rate calibration 19 subroutine SP~CAL is described below.
If the set button is pushed, the display is 21 incremented. However if it is not, after a delay for the input 22 flip flop count retrieval, the selec-tion switch code is accessed, 23 and a determination is made as to whether the switch is switched 24 to Area/Hour. If it is not, the microprocessor is returned to the main program (to be described later~.
2~ If the selection switch is on Area/Hour, a 27 determination is made as to whether the set button is pushed 28 (closed). If the pushbutton has been released, the routine again 29 returns to determine the selected switch code, and the sub-routine is returned to the main program as described above.
31 However if the set button is pushed, the area per hour 32 value is established by counting subroutine RAMP, by which the 33 display is incremented under control of the set button, and the 34 value stored for the Area/Hour i5 that shown in the display.
Turning to Figures 6A and 6B, a flow chart for the main 36 program is shown.
37 The microprocessor first determines whe-ther the set 38 button has been closed. If it is closed, then a RAMP subroutine 39 causes the display to increment progressively until the set 02 button is open.
03 If the set button is not closed, a determination i.s 04 made whether the select switch is to the width position. If it 05 is, the RWIDTH sub-routine i9 entered, by which the value on the 06 display, established by the RAMP program, is entered into a 07 predetermined memory location.
0~ If the set button is not closed, the determination i8 09 made whether the CAL position has b~en selected. If so, the sub-routine RCAL is entered, under control oE which the distance 11 calibration is made, as described earlier.
12 If the set button is not closed, a determination is 13 made as to whether the Area/Hour position has been selected. If 14 so, the sprayer calibration SPRCAL sub-routine is en-tered, which has been described earlier with respect to Figure 5b. If not, a 16 display is made as to wha-t is stored in other selected dedicated 17 memory registers as follows.
18 A determination is made as to whether the accumulated 19 flow time is greater than 100 milliseconds. If so, then the sub-routine COMFRP is entered, the one described with refe.rence 21 to Figure 5a. If the accumulated flow time is 100 milliseconds 22 or less, a determination is made as to whether bit 6 of the time 23 counter TIMCNT i5 set. If so, two seconds has passed with no 24 interrupt, and there is a forced answer with a zero result. The subroutine COMFRK, which forces a calculation of the flow, is 26 entered.
27 If the answer is no, a determination is made as to 28 whether the accumulated speed time without an interrupt is 29 greater than 100 milliseconds. If yes, the speed related parameters are calculated by a calling up of sub-routine COMSRP.
31 If not, a determination is made as to whether bit 2 of the time 32 counter TIMCNT is set, and a forced calculation is made if there 33 is no interrupt for two seconds. The subroutine COMSRP noted 34 above is therefore entered. If the answer is no, the main program is reentered as noted above.
36 The flow related parameters subroutine COMFRP flow 37 chart is shown in Figure 6b. A determination is made as to 38 whether bit 6 of the station transfer memory STM byte is set 39 (i.e., has there ever been a flow interrupt). If it is true, 7~
02 then the speed is calculated and displayed. If it i8 false, then 03 bit 7 of the station transfer memory byte is set. (i.e., is the 04 flow meter operating?). If not, the accumulation of acres (area~
05 is stopped, and the speed is displayed.
0~ The sub-routine COMFRK is looped continuously until an 07 interrup-t is received. Then the clock is read to see whe-ther the 08 interrupt is a speed or 10w interrupt. The flip flops are reset 09 and another interrupt is awaited. After 100 milliseconds the count is established. Once the time per given number of 11 accumulated interrupts is established, after 100 milliseconds, 12 the calculation routine is then entered whereupon the average 13 speed is calculated, the 10w rate, area, distance, volume, etc., 14 i.e. each time 100 milliseconds is interrupted.
The flow chart of subroutine COMFRP is shown in Figures 16 7a and 7b, the flow chart of subroutine COMSRP is shown in 17 Figures 8a and 8b, the flow chart of subroutine RCAL is shown in 18 Figures 9a and 9b, and numerous other sub-routines called up such 19 as EINTSR and TIMISR are shown in Figures lOa, lOb and lla respectively. Having described the programs COMFRP, MAIN, and 21 COMFRK in detail, it is believed that the flow charts of the 22 remaining subroutines are inherently clear, and need only be 23 followed by a person skilled in the art of microprocessors 24 understanding this invention.
The sprayer monitor described herein provides Eor 26 farmers and sprayer operators a considerably improved facility to 27 apply spray chemicalq to fields and roads with improved accuracy 28 of application, and improved economy of application, since the 2g precision of application is not left to uncalibrated assumed parameters, as in the prior art. The present apparatus provides 31 means for calibration to actual field conditions.
32 Persons skilled in the art understanding this invention 33 may now conceive of other embodiments or variations thereof. All 34 are considered within the sphere and scope of the inven-tion as defined in the claims appended hereto.
With the selector switched into the Pumped position, 36 the total volume of liquid which has passed through the ~low 37 meter is displayed. Each time a unit (i.e.gallon or liter) of 38 the chemical passes through the flow meter, the display increases 39 by one and a decimal similar unit. With the selector switch in , 02 the Spray Rate position, the application rate for the chemical in 03 e.g. gallons per acre is displayed. With the selector swi-tch set 04 to Speed, the true ground speed in e.g. tenths of miles per hour 05 is displayed.
06 When the sprayer is operated, the total area worked is 07 continuously added up. When the selector s~itch is set to Area, 08 the total area worked, e.g. in acres is displayed. When the 09 chemical fluid stops flowing, and the flow meter stops sending pulses, and the in the control unit accumulation of the sum of 11 the acres sprayed, is automatically shut off.
12 With the selector switch set to Area/Hour, the true 13 current ra-te of working the field is displayed, e.g. in acres per 14 hour. ~ith the selector switch is set to Distance, the display shows the distance in feet that the implement has moved.
16 Of course the control unit 6 can be calibrated in 17 either imperial or metric units; conversion constants to km/hour 18 for speed, litres per hectare for spray rate, hectares for area, 19 etc., can be stored in the apparatus. Indeed, an external switch for switching between the imperial and metric forms of 21 measurement can be utilized (not shown).
22 Turning now to Figure 4, a schematic of the invention 23 is shown.
24 The speed pickup described earlier, comprised of a metal detector, includes a coil 20 mounted adjacent a metal 26 extension or discontinuity on a wheel or rotating member of the 27 tractor, the rotation rate (or reciprocation rate) of which is 28 related to its assumed speed. The coil 20 is connected via a 29 shielded cable 21 to the control unit.
In the control unit, an oscillator 22 applies a signal~
31 such as at a 20 kilohertz frequency, to coil 20. The coil 20 32 carries the signal, and when a metal discontinuity passes in the 33 field, modulates the signal. The resulting modulated signal is 34 A.C. coupled via capacitor 23 to detector diodes 24. Noise spikes or the like are bypassed to ground via capacitor 25.
36 Following detection in diodes 24, the detected 37 modulation signal is A.C. coupled via capacitor 26 (after being 38 lowpass filtered by capacitor 27 in parallel with resistor 28 39 bypassing the signal-carrying circuit to ground), is applied via ~ .~ t; ,r~
02 resistor 29 to one input of comparator 30. The other input of 03 comparator 30 is connected to the tap of a resistive voltage 04 divider comprising resistors 31 and 32 connected between a source 05 of potential +V and ground. Pulse signals detected ~rom -the 06 modulated oscillator signal, which modulation was cau~ed by 07 discontinuities detected in coil 20, have their amplitudes 08 cornpared with a threshold voltage in order to avoid operation of 09 the following circuitry by noise pulses. The resulting output signal from comparator 30 is applied to the clock input of f:lip 11 flop 33. The gain of comparator 3C) is controlled by resistor 34, 12 which is connected from the Eirst-noted input of comparator 30 to 13 the junction between the two resistors 35 and 36 which are 14 connected in series between the output of comparator 30 and ground.
16 The output signal at output Q of flip flop 33 is a 17 square wave, with the number of pulses per minute being a 18 function of the vehicle speed.
19 The flow of fluid to be sprayed is detected in flow sensor 37, which produces output pulses at a rate which is a 21 function of the rate of fluid flow to the vehicle spray nozzles.
22 The flow sensor can be the type described earlier, i.e. the type 23 described in the aforenoted copending patent application, or 24 some other flow sensor which provides a pulse signal which has a rate which is a function of the flow rate of the fluid which is 26 measured . Its output signal is applied to inverting buffer 38 27 (its input also being connected to ground via a line-impedance 28 determining resistor 39~, and its output is connected to the 29 clock C input of flip flop 40. The output signal at the Q output of flip flop 40 thus is a series of pulses having a rate which is 31 a function of the flow rate of the fluid passing to the vehicle 32 spray nozzles.
33 It should be noted that the pulses applied to flip 34 flops 33 and 40 are inverted. Thus at the rising trailing edge of each of the pulses, the flip flops are clocked, and the Q
36 output goes hi~h.
37 The output signal of flop flop 33 is applied to one 38 input of NOR gate 41, and also to -the input of a tristate buffer 39 42. The output of tristate buffer 42 is connected to one lead of ,~, 02 data bus 43.
03 The output signal of flip flop 40 is connected -to the 04 second input of ~OR gate 41, and a]so to the input of tristate 05 gate 44, the output of which is connected to a another lead of 06 data bus 43.
07 With pulses being received from the vehicle speed 08 sensor or flowsensor 37, output pul3es are applied to NOR yate 09 41, which generates an output pulse signal which is applied to the interrupt input INT of a microprocessor 45. The data bu~ 43 11 is of course connected to microprocessor 45, as is an address bus 12 46, a control bu~, etc., in a manner well known to those skilled 13 in the art. Memory 47 is also connected to microprocessor 45 via 14 the bus system.
Microprocessor 45 is also connected to a plurality of 16 decoder/drivers 48a, 48b and 48c, the outputs of which are 17 connected to corresponding alphanumeric display elements 49a, 49b 18 and 49c. The connections are shown as buses, but of course the 19 outputs of the decoder/drivers are connected to the display element terminals via resistors, a representative resistor 50 21 being shown.
22 Microprocessor 45 has a plurality of outputs P20-P23 23 which are connected to inputs of a a decoder 51. An output ~6 of 24 decoder 51 is connected to the base of NPN transistor 52, the collector of which is connected to the decimal point input 53 of 26 display element 49b.
27 The timing reset input To of microprocessor 45 is 28 connected to ground via SET pushbut-ton 54 (which corresponds to 29 switch 9, Figs. 2 and 3), and also to a source of potential ~V
via resistor 55.
31 It is preferred (but not mandatory) that the 32 microprocessor and ancillary memories, etc., should be the 8000 33 family type available from Intel Corporation, such as 8035L, 34 8039/8048, 8049. A full description of the structure, operation and manner of programming this microprocessor is available in 36 many microcomputer manuals, such as MICROCOMPUTER PRIMER, by M.
37 Waite and M. Pardee, published by Howard W. Sams and Company, 38 Inc., 1976, and from Intel Corporation. A detailed description 39 thereof is therefore believed to be within the skill of a person s 02 skilled in the art, and since a detailed description thereof 03 would be redundant and unnecessary, it will not be repeated here.
04 Returning now to decoder 51, a further output Ql is 05 connected via resistor 56 to -the base of NPN transistor 57. The 06 collector of transistor 57 is connected to an alarm terminal, its 07 emitter being connected to ground. The alarm can be used to 08 alert the operator if the spray rate is being measured by no 09 pulses are being received Erom the flow sensor, for example.
An output Q3 of decoder 51 is connected via an 11 inverting buffer 58 to a controlled output -terminal, which has a 12 return lead to ground. This terminal can be used for switching 13 on -the spray pump, for example.
14 Another output Q4 of decoder 51 is connected to the reset inputs R of flip flops 33 and 40.
16 A clock source, preferably comprising a 3.579 megahertz 17 crystal oscillator (not shown) is connected in a conventional 18 manner to microprocessor 45. An internal clock divider in the 19 microprocessor applies a signal at 1/15th this rate to its ALE
output, which signal is applied to the clock input C of decoder 21 51, and also to the memory address decoders (not shown). The ALE
22 output is also connected to the clock input of a 1/4 divider 59, 23 the output of which is connected to a Tl counter input of 24 microprocessor 45.
The selector switch 8 is connected between a source of 26 potential ~V to one out of 8 inputs D0-D7 o~ a priority encoder 27 60. Each of the inputs D0-D7 is connected via a resistor 61a, 28 61b,... 61h to ground. Thus ground potential is applied via one 29 of resistors 61a-61b to each of the inputs D0-D7 unless switch 8 is switched to one of the inputs. Potential +V is appliea to the 31 encoder input to which switch 8 is connected.
32 The switch positions are preferably allocated and 33 labelled as shown: WIDTH, CAL, PUMPED, SPRAY RATE~ SPEED, AREA, 34 AREA/HOUR, and DISTANCE.
The outputs Q0-Q2 of encoder 60 are connected via 36 tristate gates 61, 62 and 63 to various leads of data bus 43.
37 A further tristate gate 64 has its input connected to 38 manual switch 66, which is connected from source of potential ~V
39 via resistor 65 to ground. The output oE tristate gate 64 is ' 1 s 02 connected to one of the leads oE data bus 43. The input of 03 gate 64 is at high potential unless switch 66 is closed, which 04 forces the input of gate 64 to low potential. Switch 66 is used 05 as an enabling input for metric or imperial conversion in 06 microprocessor 45.
07 All of the enable inputs of tristate gates 42, 44, 09 and 61-64 are connected together, and to the read RD output of microprocessor 45. The signals applied to the gates are thus 12 read when the RD output goes high.
13 The microprocessor multiplies signals representing the 14 speed of the vehicle and the spray width, and divides khe result into a signal representing the fluid flow rate to obtain the rate 16 of application to the fluid. Assuming that a signal representing 17 the spray width has been stored in the microprocessor memory 18 using the set switch 54, signals representing the speed and flow 19 rate must be received.
As noted earlier, pulses at a rate representative of 21 the vehicle speed are output from flip flop 33 and are applied to 22 one input of NOR ga-te 41 and to tristate gate 42 and pulses at a 23 rate representative of the flow of ~luid are output from flip 24 flop 40 to the second input of NOR gate 41, and to the input of tristate gate 44. With the input of a pulse from either of flip 26 flops 33 or 40, an interrupt signal is generated to 27 microprocessor 45.
28 Microprocessor 45 in response generates a read signal on the RD output, enabling all of tristate gates 42, 44, and 31 61-64.
32 Assuming that the spray rate is to be displayed, switch 33 8 had been positioned so that input D4 of encoder 60 is connected 34 to potential source ~V. The resulting encoded output signal of encoder 60 is thus applied to data bus 43 ~ia tristate gates 61, 37 62 and 63, when the read enable signal on the RD lead is 38 received. The microprocessor is thus informed that the program 39 for displaying the spray rate should be accessed.
At the same time, the pulse applied to one of the two 41 inputs of tristate gates 42 and 44 is applied to data bus 43. It 03 should be noted that a signal on the microprocessor RD output 04 will not occur if pulses are present at the output of flip flops 05 33 and 40 simultaneously, since NOR gate 41 will be inhibited;
06 the microprocessor would be confused as to which source count to 07 increment.
08 In the case of a single input pulse to NOR gate 41, an 09 output signal from only one of tristate gates 42 and 44 will be present, and is input via data bus ~L3 to microprocessor 45.
11 Having determined which lead of data bus 43 carries the input 12 pulse signal, the microprocessor est:ablishes whether the pulse is 13 a speed pulse or a flow rate pulse.
14 It was noted earlier that a signal appears on the ~LE
lead of microprocessor 45 which is 1/15th the rate oE -the cr~stal 16 oscillator, i.e. 1/15th of 3.579 megahertz. This reduced clock 17 rate is further reduced in a 1/4 divider 59, the output of which 18 is applied to input Tl of microprocessor 45, i.e., at 59,650 19 pulses per second. This further reduced rate is counted with internal counters in microprocessor 45.
21 When an interrupt arrives from the output o~ NOR gate 22 41, the internal clock count of the count from input Tl is 23 recorded. The successive clock pulse counts are also 24 subtracted, to obtain rate variations.
Assuming that in lS0 feet there are 185 speed 26 interruptions, i.e. 5.4 interruptions per second, the internal 27 clock counts about 11,000 pulses on the Tl input between speed 28 pulses. This value is internally converted to a speed rate, the 29 signals being decoded in decoder drivers 48a, 48b and 48c and are applied to display segments 49a, 4gb and 49c when the selector 31 switch 8 is switched to the D3 input of decoder 60.
32 Pulses from the flow sensor 37 occur at a much faster 33 rate, typically between 10 pulses per second and 5,000 pulses per 34 second. Microprocessor 45 recognizes the source of pulses as described above, using the count reached of the pulses on lead Tl 36 to establish the spped and flow rate value signals used in the 37 aforenoted calculation.
38 When the microprocessor determines which source, either 39 the speed or flow sensor from which the input pulses are being received, it outputs a signal to decoder 51, which applies a 02 signal to output Q4, which resets both Elip flops 33 and 40. The 03 next pu]se which is received by those flip flops thus outputs on 04 their Q outputs.
05 The microprocessor is caused to accept and store the 06 spray width calibration when switch 8 is connected to input D7 of 07 encoder 60. An encoded output signal from tristate gates 61-63 08 is applied to data bus 43, which causes the microprocessor to 09 accept count input signals on lead Tl, when pushbutton 54 is closed, applying an enable signal to input T0. The count signal 11 is displayed on display elements 49a, 49b and 49c. Successive 12 closures o~ switch 54 cause -the count swn in microprocessor 45 13 successively to increase or decrease, the result being 14 automatically stored in a memory location allocated to the width parameter.
16 When the switch 8 is set to input D6 of encocler 60, the 17 microprocessor is caused to receive input pulses from the speed 18 coil 20 via flip flop 33 and store the resulting count, as long 19 as the set pushbutton 54 is open. There~ore when calibrating the apparatus, the set pushbutton 54 is closed as the vehicle is 21 driven past a first calibration post, and immediately released.
22 As soon as the set pushbutton is open, pulses from flip flop 33 23 are applied via data bus 43 to the microprocessor, and are 24 counted, and a count displayed on display 53~ As soon as the second calibration post is reached, the set 54 pushbutton is 26 momentarily depressed, and the sum of the counts is retained in 27 memory as the speed calibration factor.
28 When switch 8 is switched to contact the D5 input of 29 encoder 60, the circuit operates similarly, except that pulses from the flow sensor 37 and flip flop 40 are accepted.
31 Switch 8 being closed to inputs D4, D3, D2, Dl or D0 of 32 encoder 60, enables the microprocessor 45 to display the spray 33 rate, speed, area, area per hour, and distance respectively on 34 display elements 49a, 49b and 49c.
A preferred algorithm for the firmware used to operate 36 the microprocessor is described below, with reference to Figures 37 5A-ll. Of course other algorithms may be designed. The 38 parameters referred to are of course names of corresponding 39 signals. Figures 5A and 5B are a flow chart of the signal logic ~ j 02 in the microprocessor for computing and displaying and 03 calibra-ting the flow rate (area per hour), and is described 04 below. This is a subroutine of a master flow chart, and is 05 described first for the purpose of better illustrating the 06 invention. These figures are intended to form an appendix to the 07 specification, rather than ~orming illustrating figures of the 08 structure of the invention.
09 It was noted earlier that -the bit rate input to input Tl of microprocessor 45 is 59,659 PPS. A signal representing 11 this number, representing the period between successive timer 12 pulses, is multiplied in a first step by the count oE the flow 13 rate pulses between interrupts.
14 Thus the accumulated flow time between the last (R3) and present (R4) interrupts is accumulated as the value 16 FLACHI,LO, which is stored in memory locations TEMP2 and Rl.
17 In the next step, the accumulated flow pulse count is 18 divided by the accumulated actual time since the last calculation 19 (counting pulses). This gives the number of pulses per second.
In order to determine the number of gallons per minute, 21 the flow rate A offset at which the flow meter star-ts to ro-tate 22 (a constant) is added to the slope of the linear characteristic 23 curve of the flow rate sensor (Bx). Bx is determined 24 experimentally, and for the flow rate sensor described in the aforenoted patent application, is the frequency x 256.
26 Accordingly in this calculation the number of pulses per second 27 is converted into a flow rate in gallons per minute, the 28 correlation having been determined experimentally. This value is 29 stored in memory locations R6 and R5.
This flow rate is multiplied by a number, the number 31 900 being used as a first approximation, and divided by a flow 32 calibration value FLOCAL, which is entered by the operator. The 33 result is stored as a flow rate value EXFLOW.
34 The flow rate EXFLOW is multiplied by FLACHI or FLACHO, and divided by a constant (546) to convert the values to gallons 36 (or a different constant to convert the value to litres).
37 This results in the value DPUMPED, a charge in the 38 amount pumpad, being stored at R6 and R5.
39 DPUMPED is then added to GALLLO, or GALLHI (gallons low 02 or gallons high), the carry bit being then propagated through the 03 value PUMPED, the amount of spray which has been pumped. Pumped 04 is then updated by the change in the amound pumped DPUMPED.
05 If the speed of the vehicle is 0, the time flow rate 06 per unit time is displayed alternatively with a code indicating 07 that it is a timed flow rate rather than an area flow rate, e.g., 08 an audible alarm is activated as dec;cribed earlier.
09 If the speed of the vehic]e is not 0, the alarm bit is deactivated, FLOW RA'rE is reloaded, multiplied by 600 ~converting 11 it into 10ths of a gallon per acre), the resulting vaLue is 12 divided by acres per hour, resulting in a spray rate value, 13 stored at R6 and R5.
14 The signal is then applied through a low pass filter to remove ripple, i.e., a time average is implemented over two to 16 three seconds, rather than to 100 milliseconds. The area sprayed 17 per hour is then displayed.
1~ Turning to Figure 5B, the spray rate calibration 19 subroutine SP~CAL is described below.
If the set button is pushed, the display is 21 incremented. However if it is not, after a delay for the input 22 flip flop count retrieval, the selec-tion switch code is accessed, 23 and a determination is made as to whether the switch is switched 24 to Area/Hour. If it is not, the microprocessor is returned to the main program (to be described later~.
2~ If the selection switch is on Area/Hour, a 27 determination is made as to whether the set button is pushed 28 (closed). If the pushbutton has been released, the routine again 29 returns to determine the selected switch code, and the sub-routine is returned to the main program as described above.
31 However if the set button is pushed, the area per hour 32 value is established by counting subroutine RAMP, by which the 33 display is incremented under control of the set button, and the 34 value stored for the Area/Hour i5 that shown in the display.
Turning to Figures 6A and 6B, a flow chart for the main 36 program is shown.
37 The microprocessor first determines whe-ther the set 38 button has been closed. If it is closed, then a RAMP subroutine 39 causes the display to increment progressively until the set 02 button is open.
03 If the set button is not closed, a determination i.s 04 made whether the select switch is to the width position. If it 05 is, the RWIDTH sub-routine i9 entered, by which the value on the 06 display, established by the RAMP program, is entered into a 07 predetermined memory location.
0~ If the set button is not closed, the determination i8 09 made whether the CAL position has b~en selected. If so, the sub-routine RCAL is entered, under control oE which the distance 11 calibration is made, as described earlier.
12 If the set button is not closed, a determination is 13 made as to whether the Area/Hour position has been selected. If 14 so, the sprayer calibration SPRCAL sub-routine is en-tered, which has been described earlier with respect to Figure 5b. If not, a 16 display is made as to wha-t is stored in other selected dedicated 17 memory registers as follows.
18 A determination is made as to whether the accumulated 19 flow time is greater than 100 milliseconds. If so, then the sub-routine COMFRP is entered, the one described with refe.rence 21 to Figure 5a. If the accumulated flow time is 100 milliseconds 22 or less, a determination is made as to whether bit 6 of the time 23 counter TIMCNT i5 set. If so, two seconds has passed with no 24 interrupt, and there is a forced answer with a zero result. The subroutine COMFRK, which forces a calculation of the flow, is 26 entered.
27 If the answer is no, a determination is made as to 28 whether the accumulated speed time without an interrupt is 29 greater than 100 milliseconds. If yes, the speed related parameters are calculated by a calling up of sub-routine COMSRP.
31 If not, a determination is made as to whether bit 2 of the time 32 counter TIMCNT is set, and a forced calculation is made if there 33 is no interrupt for two seconds. The subroutine COMSRP noted 34 above is therefore entered. If the answer is no, the main program is reentered as noted above.
36 The flow related parameters subroutine COMFRP flow 37 chart is shown in Figure 6b. A determination is made as to 38 whether bit 6 of the station transfer memory STM byte is set 39 (i.e., has there ever been a flow interrupt). If it is true, 7~
02 then the speed is calculated and displayed. If it i8 false, then 03 bit 7 of the station transfer memory byte is set. (i.e., is the 04 flow meter operating?). If not, the accumulation of acres (area~
05 is stopped, and the speed is displayed.
0~ The sub-routine COMFRK is looped continuously until an 07 interrup-t is received. Then the clock is read to see whe-ther the 08 interrupt is a speed or 10w interrupt. The flip flops are reset 09 and another interrupt is awaited. After 100 milliseconds the count is established. Once the time per given number of 11 accumulated interrupts is established, after 100 milliseconds, 12 the calculation routine is then entered whereupon the average 13 speed is calculated, the 10w rate, area, distance, volume, etc., 14 i.e. each time 100 milliseconds is interrupted.
The flow chart of subroutine COMFRP is shown in Figures 16 7a and 7b, the flow chart of subroutine COMSRP is shown in 17 Figures 8a and 8b, the flow chart of subroutine RCAL is shown in 18 Figures 9a and 9b, and numerous other sub-routines called up such 19 as EINTSR and TIMISR are shown in Figures lOa, lOb and lla respectively. Having described the programs COMFRP, MAIN, and 21 COMFRK in detail, it is believed that the flow charts of the 22 remaining subroutines are inherently clear, and need only be 23 followed by a person skilled in the art of microprocessors 24 understanding this invention.
The sprayer monitor described herein provides Eor 26 farmers and sprayer operators a considerably improved facility to 27 apply spray chemicalq to fields and roads with improved accuracy 28 of application, and improved economy of application, since the 2g precision of application is not left to uncalibrated assumed parameters, as in the prior art. The present apparatus provides 31 means for calibration to actual field conditions.
32 Persons skilled in the art understanding this invention 33 may now conceive of other embodiments or variations thereof. All 34 are considered within the sphere and scope of the inven-tion as defined in the claims appended hereto.
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A sprayer monitor for a spray vehicle comprising:
(a) means for receiving a speed indication signal comprising a plurality of pulses, the frequency of the pulses being related by a predetermined speed factor signal to the actual speed of the vehicle, (b) means for receiving a fluid flow indication signal comprising a plurality of pulses, the frequency of the pulses being related by a predetermined flow factor signal to the actual spray fluid flow rate, (c) means for storing signals representative of the spray width of the sprayer, and said speed and flow factor signals, (d) a display, and (e) control means connected to the display, the receiving means and the storing means for generating a signal representing a number of speed indication pulses received in a predetermined time and a further signal representing a number of fluid flow indication pulses received in a predetermined time, and for applying the speed factor signal to the signal representing the number of speed indication pulses received in a predetermined time to obtain an actual speed signal, and for applying the flow factor signal to the signal representing the number of fluid flow indication pulses received in a predetermined time to obtain an actual fluid flow rate signal, for multiplying the speed signal and the width signal and for dividing the result into the fluid flow rate signal to obtain a signal representative of the volume of fluid applied per unit area, and for applying the latter signal to the display.
(a) means for receiving a speed indication signal comprising a plurality of pulses, the frequency of the pulses being related by a predetermined speed factor signal to the actual speed of the vehicle, (b) means for receiving a fluid flow indication signal comprising a plurality of pulses, the frequency of the pulses being related by a predetermined flow factor signal to the actual spray fluid flow rate, (c) means for storing signals representative of the spray width of the sprayer, and said speed and flow factor signals, (d) a display, and (e) control means connected to the display, the receiving means and the storing means for generating a signal representing a number of speed indication pulses received in a predetermined time and a further signal representing a number of fluid flow indication pulses received in a predetermined time, and for applying the speed factor signal to the signal representing the number of speed indication pulses received in a predetermined time to obtain an actual speed signal, and for applying the flow factor signal to the signal representing the number of fluid flow indication pulses received in a predetermined time to obtain an actual fluid flow rate signal, for multiplying the speed signal and the width signal and for dividing the result into the fluid flow rate signal to obtain a signal representative of the volume of fluid applied per unit area, and for applying the latter signal to the display.
2. A spray monitor as defined in claim 1, further comprising a counter controlled by the control means, manual means for causing the control means to display an incrementing count from the counter on the display, and manually controlled selector means for causing the control means to store the displayed count as the speed factor signal or the flow factor signal.
3. A spray monitor as defined in claim 2, in which the selector means is comprised of a switch in a circuit adapted to generate code signals, means for applying the code signals to the control means for causing the control means to store the displayed count as one of the speed factor signal, the flow factor signal or the spray width signal.
4. A spray monitor as defined in claim 3, in which the switch and associated circuit is adapted to generate code signals for causing the control means to display one of said signal representative of a volume of fluid producing said fluid flow indication signals, a volume of fluid per unit time, said signal representative of the actual speed of the vehicle, a signal representative of a distance as determined by a total count of the speed indication pulses modified be the speed factor signal, an area signal representative of the distance signal multiplied by the spray width signal, or a signal representative of the area signal divided by the elapsed time in predetermined units.
5. A spray monitor as defined in claim 4 in which the circuit associated with the switch is an encoder having a plurality of data input terminals and a plurality of encoded data output terminals, each of said input terminals being connected to a switch terminal, means in the switch for connecting a selectable one of the input terminals to a potential source of predetermined polarity, and for applying the potential source of opposite polarity to the other input terminals, said output terminals being connected to the control means.
6. A spray monitor as defined in claim 1, 2 or 4 in which the control means is comprised of a microprocessor having an interrupt input, a NOR gate having its output connected to the interrupt input, means for applying the speed indication pulse signals and the fluid flow indication pulse signals to respective inputs of the NOR gate, and to inputs of respective individual transmission gates, the outputs of the transmission gates being connected to data bus inputs of the microprocessor, means for enabling the transmission gates by the microprocessor upon reception of a signal at said interrupt input, whereby one of the speed indication or fluid flow indication pulse signals is passed through an associated transmission gate to the microprocessor for counting and determination of its source.
7. A spray monitor as defined in claim 5, in which the control means is comprised of a microprocessor having an interrupt input, a NOR gate having its output connected to the interrupt input, means for applying the speed indication pulse signals and the fluid flow indication pulse signals to respective inputs of the NOR gate, and to inputs of respective individual transmission gates, the outputs of the transmission gates being connected to data bus inputs of the microprocessor, means for enabling the transmission gates by the microprocessor upon reception of a signal at said interrupt input, whereby one of the speed indication or fluid flow indication pulse signals is passed through an associated transmission gate to the microprocessor for counting and determination of its source.
8. A spray monitor as defined in claim 7, further including a speed indication signal generator comprising a carrier signal oscillator, a flow rate indicator for generating modulating signals connected to the output of the oscillator, a detector for the modulation signals imposed on the carrier signal connected to the output of the oscillator, a low pass filter connected to the output of the detector, a comparator connected to the output of the filter for passing signals applied thereto in excess of a predetermined threshold, and a flip flop having its clock input connected to the output of the comparator, one output of the flip flop being connected to one input of the NOR
gate.
gate.
9. A spray monitor as defined in claim 8, the indicator including means for applying pulse signals from a metal detector, the metal detector being located adjacent a turbine having metal elements in a plurality of turbine paddles which is adapted to be disposed in a fluid line, to the clock input of a second flip flop, one output of the second flip flop being connected to a second input of the NOR gate.
10. A spray monitor as defined in claim 9, further including circuit means connecting the microprocessor and the flip flops for resetting both flip flops upon detection of an interrupt signal from the output of the NOR gate.
11. A sprayer monitor for a spray vehicle comprising:
(a) means for sensing the speed of movement of the sprayer and for providing a first signal representative of said speed, (b) means for sensing the rate of flow of a fluid to be sprayed and for providing a second signal representative of said rate of flow, (c) means for storing a signal representative of the spray width of the sprayer, (d) a display, and (e) control means for receiving said signals and for generating a display operating signal and applying it to the display, which corresponds to the value of the second signal divided by the product of the first and third signals, representing the values of fluid sprayed per unit acre.
(a) means for sensing the speed of movement of the sprayer and for providing a first signal representative of said speed, (b) means for sensing the rate of flow of a fluid to be sprayed and for providing a second signal representative of said rate of flow, (c) means for storing a signal representative of the spray width of the sprayer, (d) a display, and (e) control means for receiving said signals and for generating a display operating signal and applying it to the display, which corresponds to the value of the second signal divided by the product of the first and third signals, representing the values of fluid sprayed per unit acre.
12. A sprayer monitor as defined in claim 11, in which each said means for sensing is comprised of means for generating pulses at rates representative of said speed and said fluid flow rate respectively, and in which the control means includes means for receiving said pulses, a clock, means for counting clock pulses, and means for registering the clock count reached each time one of said pulses is received, and for storing said successive clock counts as signals representative of said speed and flow rate.
13. A sprayer monitor as defined in claim 12, further including means for applying a sequentially changing number signal to said display, means for stopping the sequential change of said number, and means for entering a signal corresponding to the displayed number into the storage means as said third signal.
14. A sprayer monitor as defined in claim 11, 12 or 13 in which the means for sensing said speed is comprised of a metal detector for detecting a target mounted on a portion of said vehicle adapted to cycle with movement of the vehicle.
15. A sprayer monitor as defined in claim 11, 12 or 13 in which the means for sensing the rate of flow of said vehicle is comprised of a turbine adapted to rotate under the influence of flow of said fluid and a circuit adapted to generate pulses upon detection of the rotation of said turbine.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000363076A CA1167145A (en) | 1980-10-23 | 1980-10-23 | Sprayer flowmeter |
| GB8132061A GB2087566A (en) | 1980-10-23 | 1981-10-23 | Field sprayer monitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000363076A CA1167145A (en) | 1980-10-23 | 1980-10-23 | Sprayer flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1167145A true CA1167145A (en) | 1984-05-08 |
Family
ID=4118228
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363076A Expired CA1167145A (en) | 1980-10-23 | 1980-10-23 | Sprayer flowmeter |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1167145A (en) |
| GB (1) | GB2087566A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2145830A (en) * | 1983-09-01 | 1985-04-03 | William Moore Fennell | Monitoring performance of a mobile agricultural machine |
| GB8330758D0 (en) * | 1983-11-18 | 1983-12-29 | Montandon B | Distributing device |
| US4803626A (en) * | 1987-09-15 | 1989-02-07 | Dickey-John Corporation | Universal controller for material distribution device |
| IE904565A1 (en) * | 1990-12-18 | 1992-07-01 | Comet Technology Ltd | A Monitoring Apparatus |
| US6195604B1 (en) | 1996-09-09 | 2001-02-27 | Agco Limited | Tractor with monitoring system |
| US6823249B2 (en) | 1999-03-19 | 2004-11-23 | Agco Limited | Tractor with monitoring system |
| US10654062B2 (en) | 2015-07-22 | 2020-05-19 | Irrigreen, Inc. | Irrigation system |
| CN108739730B (en) * | 2018-05-02 | 2021-02-12 | 江苏大学 | Active prediction and adjustment system and method for spray rod balance |
| CN109566580A (en) * | 2018-11-27 | 2019-04-05 | 广州极飞科技有限公司 | Plant protection equipment, intelligent container, plant protection device systems and sprinkling control method |
-
1980
- 1980-10-23 CA CA000363076A patent/CA1167145A/en not_active Expired
-
1981
- 1981-10-23 GB GB8132061A patent/GB2087566A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB2087566A (en) | 1982-05-26 |
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| MKEX | Expiry | ||
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