The curtain can be closed for two purposes:
- To save energy (energy function)
 - To protect the crop against too much radiation from the sun (shading function)
 
The setpoints for curtains can be found as follows:
Energy curtain
The curtain is closed as energy curtain under 3 conditions:
- Outside temperature is too low 
 - Greenhouse temperature is too low
 - The period is released
 
If the curtain is closed as energy curtain, a crack can be set.
If the outside temperature measurement is below 2 °C, condition 1 is met. 
If the greenhouse temperature measurement is below 17 °C (20-3), condition 2 is met. 
The condition can be switched off by setpoint "temperature difference: release" to 40 °C.
Between sunset and 1 hour after sunrise, condition 3 is met.
 
The crack in the curtain is 2%.
Example 1:
Close the energy curtain if the outside temperature during the day is below 2 °C  and during the night below 12 °C.
Example 2:
Crack in the energy curtain of 2% if the measured RH in the greenhouse reaches 95%.
 
Shading curtain
The curtain is closed as shading curtain if the measured radiation is too high.
As soon as the measured radiation is higher than 700 W/m2, the shading curtain becomes active. The curtain is set to minimum position, in this case 80%.
The P-band is used to further close the crack. At 1000 W/m2 (=700+300), the curtain is at its maximum position, in this case 100%.
Example: 
The calculated position of the curtain with increasing radiation.
Radiation W/m2
   | Calculated curtain position %
   | 
650
   | 0
   | 
700
   | 80
   | 
800
   | 87
   | 
900
   | 94
   | 
1000
   | 100
   | 
1050
   | 100
   |