In smaller sized greenhouses, a manual system opened and closed by hand could possibly be installed. These work simplest when the screen material is supported by a monitor system.
Start time – when in the morning will the screen system start operation
Stop period – when in the afternoon will the screen system stop operation
Light level – at what light strength will the screen become activated either to open up or close
Maximum/minimum temperature – what exactly are the limitations of temperature desired
Maximum/minimum humidity – What exactly are the limits of humidity desired
Gap positions – this sets the percent open up or close placement under different circumstances such as early on a winter early morning to reduce thermal shock or Rack Drive For Greenhouse through the summer to provide better shading. The gap measures and speed of motion can be controlled in some systems.
Time delay – below changeable weather conditions this avoids frequent opening and closing
Wind speed – To reduce warmth loss, the screen can be closed early under high wind speed conditions
Snow detection – this can open the screen and turn on heat when it starts to snow.
The typical system uses nylon monofilament or stainless steel cables to support the screen material. The screen material can either rest along with the network of cables or be suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that movements the industry leading of the screen material. Control is usually either with a manual change or electronic controller.
Based on the above, the grower is required to enter the next parameters in to the controller:
A weather station is required to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.