Opening and closing can be in relation to sunrise / sunset, light intensity or fixed time.
Thermal Shock Protection:
A temperature sensor is installed above the curtain to permit a progressive opening in order to reduce or eliminate thermal shock to the plants.
Partial Opening for Venting:
When the curtain is closed and if a roof venting demand occurs, there will be a partial opening done in order to permit hot or humid air to be evacuated.
Should the light intensity exceed a user defined parameter, the curtain will partially deploy to protect the crops but also permit venting. If both energy and shade curtains are installed then both curtains will work according to their respective programs.
Opening and closing are normally done according to fixed time.
Wall Blackout Roll-ups:
In order to produce total darkness, wall blackout roll-ups are normally installed and they will operate as per the blackout curtains.
Light intrusion detection:
A light sensor can be installed and would generate an alarm should a problem occur such as a shade panel not closing, lights remaining on or an operator error.