Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to irrigation control
systems and, more particularly, to digitally programmable
control systems.
When using irrigation systems to artificially grow
plants, the most desirable growth is achieved when sufficient,
but not excessive, amounts of water are delivered to the
plants for precise periods at precise intervals. A large
number of irrigation control systems currently being used
are mechanically controlled by timing motors having adjust-
able pins which actuate con-tacts providing control signals
for irrigation water valves and the like. Modern growing
techniques practiced by greenhouse operators now demand much
more precise control. For example, commercial flower
growers irrigate their plants for only two or three seconds
at a time, but at intervals which may exceed one hundred
fifty times a day. Cucumber growers irrigate their plants
for 2 l/2 minute periods but at intervals of up to thirty
times a day, with half-hour periods between intervals.
Sometimes it is impossible for a grower to estimate in
advance the irrigation program for his plants so that, if
the plants are not properly monitored, they may be improperly
watered or, under certain conditions, drv. Control of prior
irrigation systems required monitoring and manual operation
by the growers.
The present invention offers a solution to the
above mentioned and other irrigation problems by providing
programmablQ digital system for the automatic control of a
plurality of irrigation valve stations. In the system, the
timing se~uence and amounts of water to be provided to
various areas are accurately preprogrammed in advance. An
automatic startup of the programmed digital irrigation
system is responsive to strategically located sensors which
indicate a lack of moisture. The system may be activated
automatically evexy twenty-four hours to follow a given
sequence in which the number of watering cycles, the dura-
tion of a cycle for each individual station, and the inter
val between watering cycles are programmed in advance.
In accordance with these and other objects of the
invention, a programmed digital system for automatic control
of a plurality of irrigation valve stations is provided
which basically makes it possible for a grower to accurately
preprorgram the irrigation schedule for his plants. Certain
of the valve stations are selected for operation, and these
valve stations are activated in sequential order for prede-
termined time periods. The valve stations are activated,for example, by a plurality of programmed station counters,
each of which has a respective output terminals for con-
trolling a respective valve station. Associated with each ;~
station counter is a switch which, in a first position,
connects a signal to enable the counter and provide anoutput from each counter. The switch, in a second position,
bypasses its counter. The preselected sequence is cyclically
repeated for a selected number of additional preselected
sequences, and preselected intervals are provided between
each of the additional sequences. This is accomplished
using, for example, a programmed cycle counter and a programmed
interval counter, with the outputs thereof gated together to
initiate operation of a valve activation sequence. The
entire sequence is activated at a preselected time of day;
and means for displaying the preselected time of day, as
well as the time of day, are also provided. The sequence is
also initiated by the sensing of an operating condition by a
demand sensor device. When the various valve stations are
activated a pump for delivering ~ater under pressure to the
irrigation valve stations is also activated. I'he system is
economically constructed using conventional logic components
or subsystems.
More specifically, a device according to the
present invention may be defined as a programmable digital
irrigation control which comprises first means for acti
vating selected ones of the valve stations in a preselected
sequence for predetermined time periods, and second means
for repeatedly cycling the first valve station activating
means through a selected number of preselected sequences
with preselected intervals being provided between the
sequences.
In the drawings which illustrate a preferred
embodiment of the invention.
Figure 1 is a block diagram of a programmed
digital system for automatic control of a plurality of
irrigation valve stations;
Figure 2 is a schematic diagram of a clock circuit
and a soil condition circuit for operating the irrigation
control system on demand,
Figure 3 is a schematic diagram of an irrigation-
sequence cycle counter and an interval counter according tothe invention,
Figure 4 is a schematic diagram of counter circuits
providing clock pulses to operate various counters,
Figure 5 is a schematic diagram of a typical valve
station counter,
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Figures 6~ and 6B respectively are schematic
diagrams showing a power supply circuit and irri~ation valve
as well as pump control relays, and
Figure 7 is a plan view of a front panel of the
present control unit.
Referring to the drawings, in Figure 1 there i5
shown a block diagram of the progra~able digitial system
for automatically controlling operation of a plurality of
irrigation valves 10, 11, 12 and a pump controlled by a
starting block solenoid 14. The number of irrigation valves
associated with the description of the invention is optional,
and three are shown only for exemplary purposes.
Power to operate this system is provided by an AC
power line 20 to a power supply 22 which provides a positive
12 volts and a positive 5 volts, respectively, at output
terminals 24, 26 for the circuits of this control system.
Stand-by power for the positive 12-volt supply is provided
by a battery charger circuit 27 which charges a standby
storage battery 28. A blocking diode Dl directs current to
the output terminal 24 when the power supply is interrupted.
Primary timing for the system i5 provided by a
crystal controlled, time-base generator 30 which provides 60
Hz output pulses on a signal line 32 to a digital clock
integrated circuit 34. Controls 36 for setting the time of
day and the time at which the system is to be activated, as
well as a display 38 for both, are connected to the digital
clock integrated circuit 34. The digital clock integrated
circuit 34 provides a 1 Hz output pulse on signal line 40 to
a setup-operate switch 42. During initial startup of the
system, when power is first turned on, the switch block 42
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is set so that 1 H~ pulses from the clock integrated circuit
34 are connected on respective signal lines 44, 46, 48 to
the clock input terminals of an interval counter 50, a cycle
counter 52, a No. 1 station counter 5A, a No. 2 station
counter 56, and a No. 3 station counter 58. The purpose of
setting the switch block 42 is to provide the 1 Hz pulses to
the various counters to initially set all of the counters to
their maximum counts in readiness for system operation.
A number of blocks designated as program selectors
51, 53, 55, 57, 59 program the number of counting steps of
their respective counters. Cloc~ pulses for operation of
the station counters 54, 56, 58 are provided by a time
increment generator No. 1 circuit 60 which provides output
pulses with a one-minute period at terminals 62 of a double
pole, signal throw switch Sl and which also provides output
pulses having a one-second period at terminal 64 of switch
Sl. Terminal 66 of switch Sl feeds the one-minute pulses to
the station counters 54, 56, 58 when they are used, for
example, in a system for vegetable growing, and the one-
second pulses are used, for example, by flower growers. Theone-minute pulses from the time increment generator No 1
circuit 60 are fed on a signal line 68 to the input of
another countdown circuit, designated as time increment
generator No. 2 circuit 70, which provides an output signal
having a period of three m:inutes at terminal 72 of a double
pole, double throw switch S2. At terminal 74 of switch S2
is provided an output signal having a period of thirty
minutes. The output terminal 76 of the switch S2 is connec-
ted by a signal line 78 to the input terminal of the pro-
grammed interval counter 50, which is programmable to count
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from one to fifteen s-teps of the input clock signals.
Flower growers use the three-minute periods, and vegetable
growers use the thirty-minute periods.
The station counters 54, 56, 58 each have their
respective outputs cGnnected to one of the water valves lO,
ll, 12. Diodes D2, D3, and D4 respectively are connected to
the station counter outputs and to the pump start solenoid
14, which activates the pump for the system. The station
counters 54, 56, 58 are arranged for sequential activation
with a series of double pole, double throw switches S3, S4,
S5. Each switch is connected to its respective station
counter, as exemplified by the connection of switch S3 to
the No. l station counter 54. When the No. l station
counter 54 is selected for operation, the switch S3 connec-
tion arm (connecked to the terminal 80) is connected toterminal 82, which is connected to the enable input of the
station counter 54. Terminal 86 is connected to the switch
terminal 84, which is in turn connected to the countdown
terminals of tthe station counter 54. When switch S3 is
connected in this manner, the station counter 54 is enabled
by a signal at terminal 82 to count a predetermined number
of input pulses as determined by the program selector 55.
During the time that the counter is operating, the valve lO
is activated to irrigate the area associated therewith.
When -the predetermined number o~ input pulses are counted,
the valve lO is shut off and an output pulse is provided to
terminal 84 of the switch, which is connected to the next
selected station counter in the sequence. If it is desired
to not include the station in the sequence, the switch S3 is
set to the other position, such that terminal 80 is connec-
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ted to -terminal 88 and terminal 86 is connected to terminal
90, with terminals 88 and 90 being shorted together. This
connection bypasses the station counter so that it is not
enabled and so that no activation of the water valve 10 is
provided.
The other station counters and their associated
switches are similarly connected. An output terminal 100 of
switch S5 is connected to the input of a cycle multiplier
circuit 102, which is a programmed counter having the number
of counter steps determined by a selector circuit 104, which
is, for example, a multi-position rotary switch. The cycle
multiplier circuit 102 provides an output after a predeter-
mined number of operations of the last station counter in
the preselected sequence. The output of the cycle multiplier
102 is sent to a signal line 106 to the input of the cycle
counter 52. The cycle counter counts the number of cycles
of the station counters as determined by the program selec-
tor 53 and the cycle multiplier selector 104. The output of
the cycle counter 52 is fed to a gate 108 which also re-
ceives the output of the interval counter 50. The output of
20 gate 108 enables the No. 1 station counter 54, or the first
counter selected b~ the switches S3, S4, and S5.
Both the cycle counter 52 and the interval counter
50 are loaded with their respective count numbers provided
by their respective program selectors 53, 51 by an output
signal from the digital clock integrated circuit 34 at a
preselected time which is preprogrammed by the time setting
control circuit 36. Upon being loaded, the cycle counter
52 and the interval counter 50 both provide an output pulse
to activate the gate 108. The gate then provides a signal
-to terminal 80 of switch S3 which enables station counter
54, or the first sta-tion counter in the sequence programmed
by the switches S3, ~4, and S5. No output from the gate 108
is obtained for another sequence until the interval counter
has completed an interval count having from one to 15 three-
minute or thirty-minute steps. At the end of an interval
count, an output pulse is provided f~om the interval counter
to the gate 108, which provides a signal for enabling the
first station counter in the sequence. The interval counter
thus provides a time delay between reactivation of the
station counters for each sequence. The station counters
are repeatedly reactivated for a number of times, as deter-
mined by the preprogrammed counts set for the cycle multi-
plier 102 and the cycle counter 52. Station counters which
are not selected are bypassed by means of the switches S3,
S4, and S5.
The sequence of operation of the station counters
can be started any time that an external sensor 110 deter-
mines that soil conditions, or the like, are such that the
system should be activated. When that condition occurs, the
external sensor 110 provides a signal to a program-advance
generator 112 which operates through the interval counter
circuit 50 to provide an output from the gate 108. The
external sensor 110 starts one program sequence at any time
to accomodate for example, soil moisture conditions which
are unforeseen.
The detailed circuits for the functional blocks of
the system shown in Figure 1 are shown in more detail in
Figures 2 to 6. These circuits use conventional, readily
available, integrated circuits and discrete circuit components.
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~ igure 2 shows the digital clock integrated
circuit 34, which is commercially available as a National
Semiconductor Company integrated circuit MM5387AL and which
provides output signals to activate the segments of the
time-display module 38, which is a commercially available
light emitting diode display module driven by the digitial
clock integrated circuit 34. The time setting controls 36
for the digital clock integrated circuit are switches. r~he
digital clock integrated circuit 34 provides a 1 Hz output
clock on signal line 40 to a level-shifting transistor
circuit 101 which converts the MOS-compatible output signals
of the digital clock integrated circuit 34 to TTL signal
levels. An oscillator and divider circuit 113, such as a
commercially available unit provided by the National Semi-
conductor Company as ~M5369, is stabilized by a 3.58 MHz
crystal 114 and provides a divided-down 60 Hz output signal
on the signal line 32. A circuit designated 116 is a
booster circuit providing a negative 10 volts to the digital
clock integrated circuit 34 from the 12-volt power supply.
The digital clock integrated circuit 34 provides a start
pulse for the system at a particular preset time. The start
pulse output terminal of the digital clock integrated
circuit 34 feeds the start pulse to a dual, single-shot
multivibrator circuit 118 which provides a counter-reset
signal and an inverted start pulse signal. The soil probe,
or external sensor 110, is connected to one input of a
voltage comparator 120, which has its other input connected
to an adjustable reference potential. The output of the
voltage comparator 120 is fed to an input to one of the
stages of the dual single-shot multivibrator circuit 118,
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which provides an advallce-start output signal for the
program-advance generator 112 of Figure 1.
Figure 3 shows counter circuits for the cycle
multiplier circuit 102, with the multiplier selector circuit
104 function being provided by switches as shown. The cycle
counter circuit 52 of Figure 1 is shown in Figure 3 as a
four-bit counter, with the program selector circuit 53
function beir~g provided by four switches. The interval
counter 50 is a four-bit program counter, with the program
selector circui~ 51 function also being provided by four
switches. Gate 108 receives the output of each of the
counters 52, 50, and provides a signal to start the sta-tion
counter sequence as shown. The setup-operate switch circuit
42 of Figure 1 is provided by the switches shown in Figure 3
which gate 1 Hz pulses to run the various counters to their
maximum counts.
Figure 4 shows a prograr~med counter configuration
which functions as the time-increment generator No. 1l 60 of
Figure 1. Another counter circuit configuration corresponds
to the time-increment generator No. 2, 70 of Figure 1.
These circuits provide the clock pulses to operate the
station counters and the interval counter for either flower
growing or vegetable growing applications.
Figure 5 shows a typical arrangement for the
programmed counter circuits corresponding to the No. 1
station counter 5~ of Figure 1 and the No. 2 station counter
56, along with their corresponding bypass switches S3, and
S4. The output of the gate 108 is provided to terminal 30
of switch S3, which activates one-half of a dual single-shot
multivibrator circuit 120 which half, in turn, activates the
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programmed station counter 54O The o-ther halE of the dual
single-shot multivibrator circuit 120 activates the No. 3
station counter 56 upon receipt of an output signal from the
No. 1 station counter. The output of the No~ 1 station
counter 54 is fed to a transistor 122, which provides an
output signal at terminal 124 to operate a relay for the
water valve 10, as shown in Figure 1. The output of the No.
1 station counter 54 is also fed through the diode D2 to a
transistor circuit 126, the output of which is connected to
a pump-relay terminal 128 to operate the pump-start solenoid
14, as indicated in Figure 1. The No. 2 station counter is
selected by switch S4 to be one of the preselected sequence
of valve stations which are repeatedly activated under the
control of the cycle counter 52. Circuits for the other
stations have the same configuration as that shown in Figure
5.
Figures 6A and 6B show circuit diagrams for a
power supply, a voltage regulator, and a standby ~attery
circuit. These figures also shows a typical relay circuit
for operating valves corresponding to six station counters
and for operating the pump supplying water to the valves. A
typical circuit is shown in connection with the No. 1
station. A relay common terminal 130 of Figure 6B has a
positive voltage applied thereto for operating the relay
coils. When a terminal 124 is switched to a low condition,
current flows through its relay coil 132 to operate its
relay contacts 134, which provide a ground to the appro-
priate output terminal to operate the valve corresponding to
station No. 1. The other relays for the other valves are
similarly operated.
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Figure 7 shows the front panel of the present
programmable digital irrigation control. On this panel, the
digital clock 34 appears on the elft near the top with the
time setting controls 36 for the clock appearing above the
display. The interval counter 50 and the cycle counter 52
are located near the clock at the top of the panel. At
about the center of the panel, the counters 54, 56 and 58
with their associated controls are arranged in a transverse
row. It will be noticed that six counters appear on the
face of the panel while only three have previously been
mentioned. The particular unit, of course, is intended to
control watering in six separate areas hence the number of
counters provided on the face panel. The present unit
provides for separate advance programminy including ~a)
start-up time for the first watering, (b) number of watering
cycles per day (c) time intervals between cycles, and (d)
length of watering for each of the six areas .
Near each counter there is a manual override
circuit which makes it possible to delete any of the area
stations from the watering cycleO Counter 54, for example,
has a switch 130 operable to provide manual or automatic
control for that particular station. A push-button trigger
switch 131 is provided alongside the sw,itch 130 to allow the
operator of the unit to manually activate watering in any
area. Between these two switches there is an indicator
light 132 which informs the operator when activation has
taken place. The entire irrigation system is revealed to
the operator from a study of the face panel so that the
system is easy to operate as well as reliable and accurate.
While a particular embodiment of the invention has
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been shown and described, it should be understood that the
invention is not limited thereto since many modifications
may be made. It is therefore, contemplated to cover by the
present application any and all such modifications which
S fall within the true spirit and scope of the basic under-
lying principles disclosed and claimed herein.
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