Programming ET Mode

Programming In User with ET Mode

Programming a station in User with ET mode allows you to program in the number of minutes per cycle and number of cycles per day while using ET weather data to adjust irrigation amounts to meet plant needs.

Reference ET and weekly ET numbers are used to adjust watering. The reference ET is a historical number based on location and time of year. The weekly ET is an average number based on current weather.

Irrigation will still occur at the times you programmed in; however, runtimes will vary if the reference ET and Weekly ET numbers do not match. The bullet points below explain what will happen if the ET numbers do not match. 

• Equal ET: If the current weekly ET matches the station reference ET (normal weather) then the station will deliver exactly the runtime that is programmed.
  
  
• High ET: If the current weekly ET is higher than the station reference ET (hotter weather) then the station runtime will be turned up in response.
  
  
• Low ET: If the current weekly ET is lower than the station reference ET (cooler weather) then the station runtime will be turned down in response.

Steps for Programming a Station in User with ET

1.  Press STATIONS. The SELECT STATION screen displays.

2.  Press + or – to select the desired station.

3.  Press à to assign the selected station to a mode.

4.  Press + or –  to select User with ET.

5.  Press à. The SELECT PROGRAM screen displays.

6.  Press + or – to assign the station to a program.

7.  Press à until the USE WATER WINDOW screen displays.

8.  Press + or – button to perform one of the following options:

• To set the controller to not use the water window, select no (irrigation can occur outside the water window).
• To set the controller to use the water window, select yes (irrigation will only occur within the water window).

9.  Press the à button until the USABLE RAINFALL screen displays.

10.  Press + or –  to perform one of the following options:

• To set the controller to use 100% of the usable rainfall select 100%
• To set the controller to NOT use the rainfall, select None

11.  Press à until the RUNTIME PART 1 screen displays.

12.  Press + or –  to select the number of whole minutes you want this station to irrigate for.

13.  Press à. Press + or – to select the number of fractions of a minute you want to irrigate for.

14.  Press à. The NUMBER OF CYCLES screen displays.

15.  Press  +  or - to select the number of cycles for the desired station.

16.  Press the à. The SET SOAK TIME screen displays.

17.  Press  + or -   to select the number of minutes in between each cycle.

18.  Press à to set the reference ET part 1.

19.  Press + or –  to select the whole reference number.

20.  Press à to set the reference ET part 2.

21.  Press  + or –  to select the part reference number.

22.  Your station has now been set to operate in User with ET. Repeat the above procedure for additional stations that you want to operate in User with ET.

ET Backup

Setting the Maximum Backup ET

Setting the Maximum Backup ET ensures that your WeatherTRAK controller will provide sufficient irrigation in the event that it loses communication. Your maximum backup ET number is based off the maximum weekly ET the site may experience. The controller uses the maximum ET in combination with a monthly seasonal curve that simulates a typical annual weather pattern. The maximum backup ET number is in weekly inches. Backup ET values can be set from 0.50” to 3.99” per week in 0.10” increments. As a general reference, a maximum backup ET is typically set between 1.7” and 3.5” per week depending on the site’s climate.

1.  Press the SETUP button.

2.  Press the à button until the MAX BACKUP ET PART 1 screen displays.

3.  Press the + or – button to change the value of the number to the left of the decimal.

4.  Press the à button. The MAX BACKUP ET PART 2 screen displays.

5.  Press the + or – button to change the value of the number to the right of the decimal.

Setting ET

Setting Weekly ET

Weekly ET values can be set on a weekly basis as needed.

1.  Press the ET button.

2.  Press the à button until the Set Weekly ET Pt. 1 screen displays (ET06).

3.  Use the + or – button to adjust the whole number value, the value to the left of the decimal.

4.  Press the à button.  

5.  Use the + or – button to adjust the value to the right of the value.

6.  Press the à button. The Set Weekly ET Pt. 2 screen displays (ET07).

7.  Use the + or – button to adjust the whole number value, the value to the left of the decimal.

8.  Press the à button. 

9.  Use the + or – button to adjust the value to the right of the value.

Viewing ET

To View Daily ET

1.  Press the ET button. ET01 screen displays the current daily ET value, noted by the date and time it was downloaded.

• If a “P” is displayed, the ET was received during an irrigation schedule. When the irrigation schedule is complete, the ET rate will be applied.
  
  
• If an “I” is displayed, an incremental ET has been sent to offset the depletion values. This can occur when a severe change in weather has occurred.

To View Weekly ET

1.  Press the à button. ET02 screen displays the average weekly ET value.

Custom Plants

Crop coefficients for custom plants can be viewed and adjusted through the ET menu. A crop coefficient is the plant specific factor of ET observed for the crop studied over that for the well-measured reference crop under the same conditions. WeatherTRAK controllers provide the flexibility to set custom crop coefficients. This can be useful where specialty plants or native plants have unique watering requirements.

1.  Press the ET button.

2.  Press the à button until the Custom Kc Plant A screen displays (ET03). To adjust for Plant B, press the à button again.

3.  Use the + or - button to adjust the values.

Turf

Crop coefficients for turf can be viewed and adjusted from the ET menu. The custom turf Kc value can be edited on a monthly basis as needed. Custom Kc’s for turf could be used for specialty grasses such as Fescue or Bermuda grasses used in cultured landscapes. The range of Kc values is 0.1 to 1.20 in 0.10” increments. Every month requires a Kc value.

1.  Press the ET button.

2.  Press the à button until the Custom Kc Turf screen displays (ET05). Jan is the default month, and will display in the right corner of the screen. The default value is 1.00.

3.  Use the + or – button to adjust the value.

4.  Press the à button to go to the next month.

5.  Use the + or – button to adjust the next value.

6.  Continue with steps 4 and 5 until you have set Kc values for the entire calendar year.