ESP-SMTe Controller
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Evapotranspiration (ET)
The ESP-SMTe calculates water needs based on water lost
from the soil surface (evaporation) and water used by the
plants (transpiration). The rate that water is lost is called
evapotranspiration, or ET.
Plant Available Water (PAW)
The total amount of water that can be stored in the soil
for the plant is called Plant Available Water, or PAW. This
amount varies based on the soil type and plant root depth.
Management Allowed Depletion (MAD)
When the amount of water available to the plant gets too
low, irrigation is scheduled. This level is referred to as Man-
agement Allowed Depletion, or MAD and is set by the user
at the controller.
PAW - The
total amount
of water that
can be stored.
MAD - When water
drops to this level,
irrigation is
scheduled.
ET - The rate that
water is lost to
evapotranspiration.
Factors that Determine Irrigation
Configure Controller
Enter site location info and basic irrigation schedules.
To program in Advanced ET mode, select Advanced ET on
the Select Programming Mode screen. This screen is avail-
able under the Advanced Controller Setup dial position
(see page 15) or after a Factory Default reset.
Configure the controller by entering site location informa-
tion for your site, selecting the days to allow watering, and
entering the times that watering can occur.
Turn the dial to Configure Controller.
Step 1. Enter Site Location
The ESP-SMTe controller will use historical weather data
(for wind speed and humidity) based on zip code or you
can enter custom values for your site.
c
b
NOTE: If outside the United States you must use Cus-
tom Data for Location.
Select Location by Zip Code
A
Select Enter Site Zip Code.