1
Rain
Intensity
2
Rain
Barrel
(Simulated
in RG-11)
3
RG-11
Inhibit
Rain
4
Irrigation On
(Set by
Irrigation
Controller)
6:00
6:30
Inhibit Threshold
Enable Threshold
SLOWER TIME SCALE
MONDAY
SAT
SUN
TUE
WED
THU
FRI
7:00
8:00
9:00
IRRIGATION CONTROL STRATEGY
- At 6:00 AM on Monday, the irrigation controller calls for water, shown in the section 4 on the above graph. The zone
valves dutifully open and the sprinkler heads start watering the lawn. The sky is dark with heavy rainclouds, but it has not
yet started raining.
- At 6:30, it starts raining and it quickly becomes a downpour. The RG-11 detects the downpour and inhibits irrigation,
shown in section 3 on the graph. The RG-11 interrupts the current to the zone valves, and the irrigation water stops. The
irrigation controller is still calling for more water, but this is ignored, shown by the dashed lines in section 4.
- The neighbors have a disk-style rain sensor, but this has not yet accumulated enough water to shut off their system,
and their sprinklers continue during the downpour.
- By about 6:45, the Rain Barrel accumulation, section 2, in the RG-11 reaches the inhibit threshold. That is, enough
water has accumulated that the RG-11 would inhibit the system even if the "inhibit during rainstorm" feature were
disabled.
- It continues to rain hard and steady, and the RG-11 continues to record the amount of water accumulated in the
simulated Rain Barrel.
- By 8:00, so much water has accumulated that the soil is saturated. The pouring rain that continues now runs off the
soil and into the storm sewers. The RG-11 stops recording additional accumulation in Rain Barrel.
- At about 9:15 the storm stops.
- Over the next several days, Tuesday through Friday, the RG-11 slowly decreases the amount of water recorded in the
Rain Barrel, shown in section 2 where the line slowly decreases. Each morning, the irrigation control calls for more water,
but this is properly inhibited by the RG-11. The lawn received more than enough water for this time period on Monday.
- On Friday afternoon a short summer shower rolls through. This is enough to add a bit more moisture to the soil,
which has not yet fully dried out. The RG-11 records this in Rain Barrel, extending the time it inhibits irrigation.
- In mid-afternoon on Saturday, the accumulated water in Rain Barrel has decreased to below the turn on threshold.
The lawn has used up most of the water stored in the soil. The RG-11 stops inhibiting irrigation.
- On Sunday morning, the irrigation controller calls for irrigation. By this time the soil is dry enough to need it, and
sprinkler heads deliver the proper amount of water.
TIME LINE EXPLANATION FOR GRAPH
FOR REFERENCE– You do not need to consult for installation.
Barrel Limit
Inhibit During Storm
