Rain Master RME EAGLE User Manual page 103

RME EAGLE User Manual
8.0 ET PROGRAMMING
8.1 INTRODUCTION
Evapotranspiration (ET) is defined as the water loss that takes place on irrigated zones due to
evaporation and transpiration. Evaporation is the water transfer from the soil to the air and
transpiration is the water transfer from the plant to the air.
The main factors that influence ET includes incoming radiation (energy from the sun), outgoing
radiation (sensible energy leaving the earth), the amount of moisture in the air, air temperature and
wind speed.
ET is a feature that resides in the RME EAGLE controller. Its purpose is to improve irrigation
efficiency on a daily basis by re-computing station runtimes based on any one of the following
inputs:
1. Historical weather information.
2. Manual operator entered ET values.
3. Weather station measured ET.
4. Internet supplied ET
Any of the four irrigation programs within the RME EAGLE controller can be configured to utilize
the ET feature or to conform to a conventional programming model. If conventional programming
is desired, please disregard this chapter and do not use the front panel key labeled "ET".
In order to utilize the ET feature for a program, you must input information before your water
savings may be realized. This information includes entering site specific historical ET information,
generating a reference program, and selecting a source device which will supply the ET
information.
Once the data is established, the RME controller will automatically compare the daily ET source
value to the ET Reference value. Station runtimes are adjusted by the controller each day based
upon the daily ET (weather conditions). Water savings are achieved because the controller now
responds to environmental conditions. In a conventional program model, the station runtimes never
change unless the operator "reprograms" the controller. The ET feature allows the controller to
make intelligent decisions as if an operator were present everyday.
The remainder of this chapter addresses the setup and programming steps required to utilize your
RME EAGLE controller with ET scheduling.
8.1.1 ET Scheduling Overview
Your RME EAGLE controller has been designed to offer several different ET options to facilitate
immediate water savings, regardless of the configuration chosen. Additionally, the RME EAGLE
incorporates a "one-button" (ET key) approach in order to best serve your needs.
Page 96
Rain Master Irrigation Systems
Chapter 8 ET Programming