In smaller sized greenhouses, a manual program opened and closed yourself could possibly be installed. These work easiest when the screen materials is backed by a monitor system.
Start time – when each morning will the display screen system start operation
Stop period – when in the afternoon will the display screen system stop operation
Light level – in what light strength will the screen be activated either to open up or close
Maximum/Rack Drive For Greenhouse minimum temperature – what are the limits of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this units the percent open up or close placement under different circumstances such as in early stages a winter early morning to reduce thermal shock or during the summer to provide better shading. The gap guidelines and speed of motion can be controlled in some systems.
Time delay – under changeable weather conditions this avoids frequent starting and closing
Wind speed – To lessen temperature loss, the screen could be closed early under high wind speed conditions
Snow detection – this can open the screen and turn on heat when it begins to snow.
The typical system uses nylon monofilament or stainless cables to aid the screen material. The screen material can either rest on top of the network of cables or end up being suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that techniques the leading edge of the screen material. Control is definitely either with a manual change or electronic controller.
Based on the over, 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.