Note: Descriptions are shown in the official language in which they were submitted.
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POWER SEQUENCING METHOD
FOR
ELECTROMECHANICAL DISPENSING DEVICES
BACKGROUND OF THE INVENTION
This invention relates generally to material delivery systems
and more particularly to the control of power to the delivery
system metering devices.
In markets requiring the usage of chemicals, often hazardous
substances, the Environmental Protection Agency and other regulato-
ry bodies are imposing stricter regulations on the transportation,
handling, dispersion, disposal, and reporting of actual usage of
chemicals. These regulations, along with public health concerns,
has generated a need for products that address these issues dealing
with proper chemical handling.
To reduce the quantity of chemicals handled, the concentration
of the chemical, as applied, has been increasing. This has raised
the cost of chemicals per unit weight and has also required more
accurate dispensing systems. For example, typical existing systems
for agricultural pesticide dispensing use a mechanical chain driven
dispenser. Normal wear and tear on these mechanical dispensers can
alter the rate of pesticide applied by as much as 15%. For one
typical chemical, Force, a pyrethroid type insecticide by ICI, an
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over-application rate of 15% can increase the cost of the insecti-
cide by $750 over 500 acres.
Since many of the current pesticide systems are mechanical
systems, any record keeping and reporting must be kept manually.
The foregoing illustrates limitations known to exist in
present material delivery systems. Thus, it is apparent that it
would be advantageous to provide an alternative directed to
J overcoming one or more of the limitations set forth above.
Accordingly, a suitable alternative is provided including features
more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
In one aspect of the present invention, this is accomplished
by providing a method for actuating a plurality of electromechani-
cal dispensing devices comprising: determining a rate of actuation
of the dispensing devices; determining the number of dispensing
devices; dividing the plurality of dispensing devices into a
plurality of groups; determining a sequence time delay by dividing
the rate of actuation by the number of dispensing device groups:
actuating the first of the plurality of dispensing device groups:
waiting a time interval equal to the sequence time delay: actuating
an additional dispensing device group; and repeating the waiting
step and the actuating an additional dispensing device step until
all dispensing device groups have been actuated.
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According to a further broad aspect of the present
invention there is provided a method for sequencing the
application of electrical power to a plurality of
electromechanical dispensing devices. The method comprises
s determining the number of dispensing devices and then
determining a rate of application of electrical power to the
electromechanical dispensing devices. An operating time for
applying electrical power to the electromechanical
dispensing devices is also determined. The electro-
io mechanical dispensing devices are then divided into a
plurality of groups. A sequence time delay is then
determined for actuating the electromechanical dispensing
device groups by dividing the rate of application of
electrical power by the number of electromechanical
15 dispensing device groups. Command data is generated in
response to the rate of application of electrical power and
operating time. The command data is sent to a first set of
sub-controllers. The method also comprises waiting a time
interval equal to the sequence time delay for actuating the
2o electromechanical dispensing device groups. The command
data is then sent to an additional set of sub-controllers,
there being a sub-controller associated with each electro-
mechanical dispensing device and a set of sub-controllers
associated with each electromechanical dispensing device
2s group. The waiting step and the sending the command data to
an additional set of sub-controllers step is then repeated
until all sets of sub-controllers have received command
data. Each sub-controller applies electrical power to an
associated electromechanical dispensing device in response
3o to receipt of the command data.
According to a still further broad aspect of the
present invention the method for sequencing the application
of electrical power to a plurality of electromechanical
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dispensing devices comprises determining the number of
electromechanical dispensing devices; determining a rate of
application of electrical power to the electromechanical
dispensing devices; determining an operating time for
s applying electrical power to the dispensing devices;
dividing the plurality of electromechanical dispensing
devices into a plurality of groups; determining a sequence
time delay for actuating the electromechanical dispensing
device groups by dividing the rate of application of
~o electrical power by the number of electromechanical
dispensing device groups; generating command data in
response to the rate of application of electrical power and
operating time; sending the command data to a first set of
sub-controllers; modifying the command data to delay the
~s implementation of the command data by an interval equal to
the sequence time delay; sending the modified command data
to an additional set of sub-controllers, there being a sub-
controller associated with each electromechanical dispensing
device and a set of sub-controllers associated with each
zo group of electromechanical dispensing devices; repeating the
step of modifying and the step of sending the modified
command data to an additional set of sub-controllers until
all sub-controllers have received command data; simul-
taneously sending a start command to each sub-controller,
2s each sub-controller applying electrical power to an
associated electromechanical dispensing device in response
to receipt of the start command data, each additional set of
sub-controllers delaying the application of electrical power
to the associated electromechanical dispensing device by the
so sequence time delay included in the modified command data.
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Docket No. 2040-ID-IP
The foregoing and other aspects will become apparent from the
following detailed description of the invention when considered in
conjunction with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is a simplified diagram showing a material dispensing
system incorporating the present invention;
FIG. 2 is a side view of one embodiment of an electromechani-
cal dispensing device for use with the material dispensing system
shown in FIG. 1; and
FIG. 3 is a schematic diagram of the distributed controller
system for the material dispensing system shown in FIG. 1.
DETAILED DESCRIPTION
FIG. 1 shows a simplified diagram of a planter 20 incorporat-
ing a distributed control material dispensing system. The material
dispensing system of the present invention may be used with other
types of agricultural implements, but is primarily used with seed
planting equipment. Although the FIGURES show a single row of
planting equipment, typical planters include multiple rows, up to
24.
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Docket No . 2 04 0-ID-IP
The distributed control system consists of a main microcon-
trolley 10 which communicates to a plurality of sub-controllers 60.
The sub-controllers 60 implement commands received from the main
control unit 10 by applying electric power to a metering device 72.
The pesticide container 40 contains a memory device 85 for
retaining information pertaining to the material in the container
40 and to the metering device 72. This information is used by the
main control unit 10 and the sub-controllers 60 to properly
dispense the pesticide.
The material dispensing system shown in the FIGURES is a
distributed control system that employs a master microcontroller
computer 10 located in the operator's cab. Typically, the material
dispensing system is used in conjunction with a seed planter 20
which is attached to and pulled by a farmer's tractor (not shown).
Each row of the seed planter 20 includes a seed hopper and seed
planting mechanism 30 and a pesticide container and associated
dispensing mechanism 40. Pesticides include, but are not limited
to, insecticides, herbicides, fungicides, fertilizers and other
agricultural chemicals. This master or main controller 10
distributes command and control information via a high speed serial
communications link 50 to a plurality of individual meter systems
70. A typical agricultural planter may have up to 24 rows of seed
hopper and seed planting mechanisms 30 and pesticide containers 40.
Each row corresponds to one row in the field being planted. Each
individual meter system 70 is controlled by its own slave or row
controller 60. The meter system 70 consists of an electronic
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memory circuit 80 and a metering or dispensing device 72. The
meter system 70 is permanently attached to the pesticide container
40. Preferably, the meter system 70 is attached using a known
tamper evident securing system. The row controller 60 includes a
material flow sensor 62 which is integral with the row controller
60. The material flow sensor 62 detects the presence or absence of
flow from the pesticide container 40.
The distributed control material dispensing includes a main
~ microcontroller unit 10 with a display 12 and keypad 14 for
operator interface. A radar 16 is connected to the main control
unit 10 to provide ground speed. Ground speed is used to modify
the material dispensing rate to account for the planter's speed.
The main control unit 10 is connected to a junction box 55 by a
high speed serial communications link 50. The main controller 10
is in constant communication through the serial communications link
50 to the row control units 60 located on the planter 20.
The row control units 60 allow a method of multiplexing
signals going to the main controller 10. A main benefit is that
the main controller 10 can control a 24 row planter with only nine
wires going to a junction box 55. One pair of wires is used for
serial communications, three pairs of wires are provided for power
to the row control units 60 and to the metering devices 72. One
wire is provided for the lift switch 2l. Three pairs of wires are
used for power to more evenly distribute the current requirements.
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211 ~ 2 9 ~ Docket No. 2040-ID-IP
The main controller 10 also contains a non-volatile memory
unit, typically known as "flash" memory. Information pertaining
to the usage and application of pesticides is stored in this non-
volatile memory unit. This information is used to prepare printed
reports which meet EPA reporting requirements. Currently, farmers
prepare these written reports manually.
The junction box 55 is connected by additional portions of the
serial communications link 50 to a plurality of slave or sub-
controller units 60. Each slave unit 60 is associated with one row
of the planter 20, and is therefore referred to as a row control
unit 60. The preferred junction box 55 can connect up to eight row
control units 60 to the main control unit 10. If the planter 20
has more than eight rows, additional junction boxes 55 are
connected in series to the first junction box 55. A lift switch 21
is connected to the first junction box 55. This switch indicates
when the planter 20 is not in an operating position. Other
interfaces to the main control unit 10 may be provided such as
serial or parallel links for transmitting information to other
computer systems or printers.
The row control unit 60 has memory devices and logic devices
within to modify and implement the commands from the main control-
ler 10. The row control unit 60 reads information from a container
memory circuit 80 attached to the pesticide container 40 and
manipulates the commands from the main controller 10 to properly
operate the metering device 72. For example, if the concentration
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of pesticide on row 1 is different than the concentration of
pesticide on row 8, the row control unit 60 can modify the commands
of the main controller 10 to properly dispense pesticides from all
rows. The row control unit 60 also reads metering device 72
calibration data from the container memory circuit 80 and modifies
the main controller 10 commands to account for differences in
performance of different metering devices.
The row control unit 60 allows the possibility to completely
change the programmed functions of the main controller l0. As an
example, if a pre-programmed row control unit 60 is placed on a
liquid herbicide sprayer, the main controller 10 would be able to
read the dispenser type information and operate as a liquid sprayer
controller.
The preferred embodiment shown in the FIGURES uses one row
control unit 60 to control one metering device and memory unit 70.
A row control unit 60 can control more than one device, for
example, two metering device and memory units 70 or one metering
device and memory unit 70 and one seed hopper and seed planting
mechanism 30.
Each pesticide container 40 includes a metering or dispensing
device 72 which allows controlled application rates under different
conditions. The metering device 72 described herein is an
electromechanical solenoid driven device for dry granular material.
Other type of dispensers may be used for other materials, such as
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liquids. One type of metering device for dry granular material is
described in U.S. Patent No. 5,156,372, Metering Device for
Granular Material.
A side view of the metering device and memory unit 70 is shown
in FIG. 2. A base plate 71 is fastened to the bottom of the
pesticide container 40. An electromechanical metering device 72 is
attached to the base plate 71. The preferred metering device 72
uses an electric solenoid 74. The solenoid 74 is attached to one
end of a pivot bar 75 which pivots on pivot support 77. The other
end of the pivot bar 75 is biased into contact with material
dispensing aperture 76 by a spring 78. The solenoid 74 is
energized by the row control unit 60 to pivot the pivot bar 75 away
from the material dispensing aperture 76, thereby allowing
pesticide to flow by gravity out of the pesticide container 40.
The solenoid 74 must be sealed from the pesticide. Pesticide
entering the solenoid 74 can cause its premature failure. The
solenoid end of the pivot bar 75, the spring 78 and the connection
of the pivot bar 75 to the solenoid 74 are sealed by a cover (not
shown) to prevent entry of pesticide into the solenoid 74. The
preferred method for pivoting the pivot bar 75 and sealing the
solenoid cover is to include a round flexible washer (not shown) in
the pivot support 77. This flexible washer, sometimes referred to
a living hinge, has a small hole in the center, smaller than the
diameter of the pivot bar 75. The pivot bar 75 is inserted through
the small hole in the flexible washer. The flexible washer allows
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the pivot bar 75 to pivot and seals the solenoid cover from the
pesticide.
An electronic memory circuit 80 is connected to the solenoid
74. A multi-conductor cable 82 and connector 83 are used to
connect the electronic memory circuit 80 to the row control unit
60. In one embodiment of the present invention, the row control
unit 60 directly applies electrical power to the solenoid 74
through power wires 81. In addition to connecting the row control
~ unit 60 solenoid power to the solenoid 74, the electronic memory
circuit 80 also includes a non-volatile memory device 85. The
memory device 85 preferably is an E PROM, a non-volatile memory
device that is electrically erasable programmable memory, also
referred to as EEPROM or E2PROM.
The combination of the electronic memory 85 and the pesticide
container 40 with attached metering device 72 creates a material
container capable of electronically remembering and storing data
important to the container, the material dispensing system, and the
pesticide. Among the data which could be stored are: a serial
number unique to that container, pesticide lot number, type of
pesticide, metering calibration, date of filling, quantity of
material in the container, quantity of material dispensed including
specific rates of application, fields treated. This stored data
can be recalled and updated as needed. The stored data can also be
used by a metering controller or pumping system by accessing
specific calibration numbers unique to the container and make
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needed adjustments, by sounding alarms when reaching certain volume
of pesticide in a container, or keeping track of usage of the
container to allow scheduling of maintenance.
An alternate embodiment of the electronic memory circuit 80
includes a means for blocking the application of electrical power
to the solenoid 74, to assure that the solenoid 74 is only
energized by the material dispensing system. The electronic memory
circuit 80 can include an additional logic device which will only
J apply power to the solenoid 74 when a permissive control signal or
command data is received from the row control unit 60.
In operation, the main control unit 10 receives a desired
dispensing rate from the operator via the display 12 and keypad 14.
The main control unit 10 monitors the planter's 20 ground speed by
the radar unit 16. Using the desired dispensing rate, the ground
speed and basic dispensing characteristics for the metering device
72, command data for the row control units 60 are prepared. The
preferred dispensing control for a solenoid type metering device 72
is to use a fixed rate for actuating the metering device 72, 0.5
seconds, and vary the on time (or duty cycle) of the metering
device, 10% to 50%. The row control unit 60 modifies the duty
cycle specified by the main control unit 10 to account the actual
metering device 72 calibration data which was retrieved from the
memory device 85. The row control unit 60 continues to operate the
metering device 72 at the rate and duty cycle specified by the main
control unit 10 until new commands are received from the main
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Docket No. 2040-ID-IP
211225
control unit 10. The main control unit 10 also calculates the
quantity of material remaining in the pesticide container 40.
The row control unit 60 has a flow sensor 62 as part of its
electronic circuits. The flow sensor 62 senses the flow of
material from the pesticide container 40. The main control unit 10
can monitor the flow sensors 62 and generate visual and audible
alarms as required. The flow sensor 62 consists of an infra-red
light source positioned across from an infra-red light detector.
These two components are mounted on a printed circuit board which
is part of the row control unit 60. A hole is made in the board
between the light source and the light sensor. The dispensed
pesticide is guided through this hole by a light transparent tube.
The logic circuit associated with the flow sensor 62 monitors for
the presence of flow by intermittent interruptions of the light
reaching the light sensor. Since the pesticide is dispensed as
granular particles, proper flow will cause intermittent interrup-
tions of the light. A non-interrupted light will signal no
material flowing from the pesticide container 40. A completely
interrupted light will indicate a blockage of the tubing after the
flow sensor 62.
To operate the material dispensing system, it is necessary for
the main control unit 10 to uniquely identify the row control unit
60, metering device and memory unit 70 pairs. Each metering device
and memory unit 70 includes a unique electronic serial number in
the memory device 85. Each row control unit 60 also has a unique
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electronic serial number. When the material dispensing system is
initialized, the main control unit 10 must poll or query all the
metering device and memory units 70 and row control units 60 to
determine by serial number which units 70, 60 are attached to the
planter 20. This is sufficient identification for the system to
function. In the preferred embodiment, the operator should be able
to refer to a row and its associated seed and material dispensing
equipment as row x, rather than by the serial number of the
metering device and memory unit 70 or by the serial number of the
0 row control unit 60. To associate a particular metering device and
memory unit 70 and row control unit 60 to a particular row, a row
configuration method is provided.
The main control unit 10 is initialized in a configuration
mode with no row control units 60 connected. The row control units
60 are then connected to the main control unit 10 via the
junction boxes) 55 one at a time in the order in which the
operator would like them to represent. The first row control unit
60 connected would represent row one. This allows an operator who
prefers to work from left to right to have the left most row row 1
and an operator who prefers to work from right to left to have the
right most row row 1.
With a many as 24 rows on a planter 20, it is necessary to
control or limit the current drawn by the metering solenoids 74.
If all 24 solenoids were operated simultaneously, the current
demands could exceed the capacity of the operator's tractor.
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The rate at which the metering device 72 is operated is
typically 0.5 seconds. The metering device 72 is actually
activated at a 10% to 50% duty cycle (10% to 50% of the rate). The
solenoid is turned on at 0.5 second intervals for 0.05 to 0.25
seconds. The preferred method of varying the dispensing rate is to
keep the rate fixed and vary the duty cycle. Minimum current
demand can be achieved by sequencing the activation of each
metering device 72. The optimum sequence time is defined as:
Rate/Number of Rows. For a 4 row system operating at a rate of 0.5
seconds, the sequence time is 0.125 seconds (0.5 seconds/4). This
means that the metering devices 72 are started at 0.125 second
intervals. A variation of this sequencing is to divide the
metering devices 72 into groups, and stagger the starting times of
each group.
The system operates in the following manner: Material
dispensing begins with the main control unit 10 sending each row
control unit 60 a "start" command at the appropriate time (the
sequence time). The row control unit 60 does not actually receive
and use the sequence time value. Because of variations in the
operation of the multiple row control units 60, the row control
units 60 will drift away from the ideal sequencing. It is
necessary to periodically issue a "re-sync" at approximately one
minute intervals and basically restart each metering device 72
which re-synchronizes each row control unit 60 back to the main
control unit's 10 time base.
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211 ~ 2 9 ~ Docket No. 2040-ID-IP
An alternate power sequencing method requires the main control
unit 10 to send a sequence time or delay time to each row control
unit 60. The main control unit 10 then sends a start command to
all row control units 60 simultaneously. Each row control unit 60
then activates the associated metering device 72 after the time
delay previously specified.
The material dispensing system features and capabilities include:
Controls application rate of material under varying
operating conditions. The application rate can be set by
the operator from an operator's console or can be
automatically read from the material container meter
unit. The later technique offers an advantage in that it
does not allow the operator to enter an incorrect
application rate.
The system will not allow material application if the
material identification number for all rows do not match.
This prevents inadvertent application of two different
pesticides.
Provides actual ground speed information if a ground
speed sensor is attached. Typical ground speed sensor
include wheel rpm and radar. In lieu of a ground speed
sensor, a fixed planting speed may be entered and used to
distribute the granular pesticide material.
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The system monitors material flow and alerts the operator
to no flow, empty container, or blocked flow conditions.
The system monitors and tracks container material level
for each row.
The system provides control information and data to a
non-volatile memory for future downloading.
The system monitors the planter to allow pesticide to be
applied only when the planter is in the planting posi-
tion.
A typical usage for this system is:
1) For a new pesticide container, the metering device and memory
unit 70 is attached to the pesticide container 40 by either
the container manufacturer or at the container filling site.
2) A computer is connected to the metering device and memory unit
70 at the time of filling. The following information is
electronically stored in memory device 85:
Date
EPA chemical ID numbers
Container serial number
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Suggested doses, such as ounces per acre for root worm,
or ounces per acre for ants, etc. These rates are
specified by EPA.
Meter calibration information, depending on type of
metering device
Tare weight of the container
Weight of the full container
3) The container is sealed and prepared for shipping.
4) The end user, the farmer, buys the chemical container from a
distributor. The distributor connects the metering device and
memory unit 70 to a computer and stores the buyer's EPA
registration number, distributor's ID number and date in the
metering device and memory unit 70.
5) The end user takes the pesticide container 40 and attaches to
dispensing implement, such as planter, sprayer, nurse tank,
etc. The Main controller 10 compares the user's EPA registration
number with the EPA registration stored in metering device and
memory unit 70. If the registration numbers do not match, the
material dispensing system will not function. The main
controller 10 receives the information from the metering device
and memory unit 70 pertaining to proper application rates and
prompts the user to pick the desired rate. The row control
unit 60 reads the metering device calibration information from
the metering device and memory unit 70. This information is
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used in combination with commands from the main controller 10
to properly control the operation of the metering device 72.
The main controller 10 prompts the user to enter estimated
amount of acreage to be covered. The amount of pesticide
remaining in the containers 40 is checked and an alarm is
generated if the amount in the containers is not enough to
cover the estimated acreage. The user enters a field ID
number and any other required information such as number of
rows, width between rows, etc. The user then applies the pesticides
to the field. The main controller 10 monitors the ground
speed and changes the amount being dispensed to keep a
constant rate per acre. When the user finishes a field,
additional fields may be treated. Field data, including field
ID number, crop treated and quantity applied is recorded in
the main controller's 10 non-volatile memory. This informa-
tion may also be recorded in the metering device and memory
unit 70 for later use by the distributor or pesticide suppli-
er.
6) The empty or partially used pesticide container 40 is returned
to the distributor. Either the recorded usage information or
the current weight of the container can be used to determine
a credit for any unused pesticide.
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