Closed-Loop Irrigation Control

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Closed-Loop Irrigation Control
Sensor-Based
Precision Irrigation system
by Acclima
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Conventional Clock-Based
Irrigation Control
Manual Program
Entry
Timer Program
Execution
Occasional Manual
Correction Prompted
by Stress or Saturation
Open Loop: No Automatic Feedback to Control Moisture Level
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Evapo-Transpiration-Based
Irrigation Control
Complex Parametric
Input with Regular
Adjustment
Weather Station,
Computer and
Communications
Means
ET Enabled
Clock
Open Loop: No Automatic Feedback to Control Moisture Level
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Soil Moisture-Based Irrigation
Control
One-Time Moisture
Threshold Inputs
Feedback-Enabled
Automatic Controller
Closed Loop: Automatic Feedback Maintains Proper Root Zone Moisture
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Instability – The #1 Problem
Temperature
Water Content
Non-Digital
TDT Moisture
Sensors
Electrical Conductivity
Sensor Output is a Complex Function of all Three Input Variables
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XTra Sensor Stability -Temperature
Less Than 1%
Deviation
25
Reading in
% Water
20
1
Temperature in Degrees Celsius
50
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XTra Sensor Stability – Electrical
Conductivity
Less Than 1%
Deviation
25
Reading in
% Water
20
0
In-Soil EC in dS/m
2.5
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Saturation Area:
Heavy Nutrient and Water Loss
Root Putrefaction
Field Capacity:
Increasing
Water
Content
Very Small Percolation Loss
Allowable Depletion Limit
Permanent Wilt Point: (dead grass)
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Installing the Sensor – Techniques
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Install in representative area for the zone
Avoid depressions
Avoid high-traffic areas
Avoid large rocks, tree roots
Install in healthy turf
Remove a 60cm square turf plug
Install sensor 10cm deep
Re-compact soil around rods to original
compaction
 Replace turf plug and seal around edges
 Connect wires in a nearby value box
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Advantages – Water Savings
 System
Monitors ET in the Root Zone and
Applies Just the Right Amount of Water to
Hold Moisture in the Target Range
 All Weather, Soil and Plant Characteristics
are taken into Accurate Account in the
Measurements
 Upwards of 40% Water Savings can be
Expected over a Well-Managed Controller
Based System
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Advantages – Maintenance Savings
 Seasonal
Clock Adjustments are
Eliminated
 System Automatically Accommodates
Heavy Rains, Cool Periods, Hot Periods,
Dry Winds without Need of Adjustment.
 Initial Settings Remain Stable Year after
Year
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Advantages – Environmental Issues
 Ground
Water Contamination with
Pesticides and Fertilizers is the Result of
Over-Watering Crops and Turf.
 Enormous Reductions in Fertilizer and
Pesticide Applications are Possible with
Precision Irrigation. Eastern Oregon
Onion Fields show 50% Reduction.
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Advantages – Healthier Landscape
 Over-Watering
Drives Oxygen out of the
Soil and Putrefies Roots
 Over-Watering Leaches Nutrients and
Pesticides from the Soil
 Over-Watering Develops Fungi in the Soil
 Over-Watering Weakens Drought
Tolerance and Reinforces Over-Watering
 Under-Watering Stresses Lawns and
Promotes Weed Growth
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8701 – EZ Pro Xtra
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Simple retro-fit design
Single Sensor
Works with existing controller
Converts any 24V controller to
Sensor-based System
Easy Installation
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8710 – EZ Pro Max
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Central Control System
Water on Demand
64-Zone capacity
Run up to 16 sensors
Buit-in modem
Remote Control Access
2 Wire Connectivity
Friendly Software
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Communicating with other Devices
2-wire bus
1 valve
2 valves
1 valve
4 valves
2 valves
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2-Wire System Specifications
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Maximum distance for controller to any device:
1300m
 Maximum total paired wire load (unsheathed):
3300m
 Maximum total paired wire load (sheathed):
4950m
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CSU Site Performance
8/1 to 9/16 (2004)
Zone Type
CSU Timer
Minutes
Gear Drives 12,150
15 Zones
Spray Head 1,440
4 Zones
Total
13,590
19 Zones
Acclima
Minutes
Water
Savings
5,503
54.7%
356
75.3%
5,859
56.9%
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Clark County School District
2003 (Acclima) vs 2002 (ET)
Maxicom
Acclima
m3
3,458
2,718
mm
215.39
169.93
%ET
102%
80.6%
cost
$34,963
$27,480
savings
$7,483 (21.4%)
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