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Example settings for the Hoogendoorn iSii process computer pertaining to the Grodan 6 phase reference table.

Start time / Stop time 
The Grodan water content meter is connected to a level tray module.

  1. Start based on radiation, time or Grodan water content meter in the period: from sunrise until 2 hours before sunset:
  2. The irrigation strategy is set with an interval time and a delay time. The interval time is the minimum time between two cycles and the interval time + delay time is the maximum time between two cycles. Eg set the interval time at 15 minutes and the delay time at 45 minutes. In a very sunny day you will get a cycle every 15 minutes (= IT). At a very dark day every hour (=IT+DT).
  3. Start on radiation if the actual radiation is higher than 150 W/m² and the radiation sum is higher than 100 J/cm²

WC level during the day 
Water content decrease to 60% during the day. 

WC decrease at night | Time of 1st drain 
Regulate the decrease in the water content for the night to 8-10% on a sunny day, and to 10-12% on a darker day. Regulate at the time of first drain in 4 cycles to reach 400 J/cm² or 600 W/m². 

In this example a chart is included because there is no setting for a rate reduction with a water content meter. 
In case of using a Hoogendoorn AquaBalance (to control the saturation weight of the slab) it is possible to set a rate reduction. 

EC Supply 
The EC supply is 2.8 mS/cm on a darker day, and 2.5 mS/cm on a sunny day. 

Drain % over 24 hours 
Regulate the drain % over 24 hours to 15-25% on a sunny day and to 10-15% on a darker day. 

Frequency can be increased at such a low drain% through an influence of drain% on radiation sum start. So the lower the drain%, the lower the radiation sum (and vice versa). 

Cycle size 
The cycle size is 400 cc/m² (=ml/m²) on a darker day. On a sunny day, the first 3-4 cycles are 400 cc/m², then 300 cc/m².