Applies To

Intermatic ST01 and EI600 Series in-wall timers, newer versions with the countdown feature.

Note: Newer ST01 and EI600 timers can be identified by packaging labeled "with countdown," and by the presence of LAT and LON prompts during programming.

Question / Problem

How do I enter latitude and longitude on a newer ST01 or EI600 timer when the display does not show a decimal point and requires the tenths digit?

Common Installation / Application Conditions

• The timer prompts for LAT (latitude) and LON (longitude) during setup
• The timer accepts digits without displaying a decimal point
• The displayed value represents degrees and tenths without a decimal point. For example, -883 represents -88.3°
• The timer uses the entered latitude and longitude to calculate sunrise and sunset automatically

Step-by-Step Resolution

1. Verify That You Have the a Newer Model Timer

   Begin the programming sequence. If the timer prompts for LAT and LON, you have the updated version. If it shows NORTH, CENTER or SOUTH, this procedure does not apply.

2. Look Up Your Coordinates

   Find the latitude and longitude for your location, recorded to at least one decimal place. For example, 42.1° N and 88.3° W. This can be done using online map tools (e.g., Google Maps) or through a smartphone navigation app. 

3. Identify the Tenths Digit

   The timer requires degrees and the first decimal place. For example, the tenths digit is 3 for 88.3°, 1 for 42.1° and 0 for 40.0°.

4. Remove the Decimal Point for Data Entry

   Enter the degrees and tenths as a single number. For example, enter 88.3° as 883, 42.1° as 421 and 40.0° as 400.

5. Assign the Correct Sign

   Use a negative value for west longitude and south latitude. Use a positive value for north latitude and east longitude. For example, 88.3° W becomes -883.

6. Enter the Longitude

   At the LON prompt, enter the longitude as the combined value without a decimal point. For example, enter 88.3° W as -883.

7. Enter the Latitude

   At the LAT prompt, enter the latitude using the same method. For example, enter 42.1° N as 421.

8. Complete the Remaining Programming Steps

   Finish entering the date, time and schedules. The timer will calculate sunrise and sunset automatically using the entered coordinates.

Tips / Additional Notes

• The timer does not display a decimal point when entering latitude and longitude
• Always include the tenths digit (for example, enter -88.3° as -883)
• If your coordinates have two or more decimal places, round to the nearest tenth before converting the value for entry
• If the timer does not accept a value, confirm that you entered the degrees and tenths without a decimal point, included the tenths digit and used the correct sign
• If the calculated sunrise or sunset time appears incorrect, confirm the tenths digit, coordinate sign and rounding of the entered latitude and longitude