In smaller sized greenhouses, a manual program opened and closed by hand could be installed. These work easiest when the screen materials is backed by a track system.
Start time – when each morning will the display system start operation
Stop period – when in the afternoon will the screen system stop operation
Light level – in what light strength will the screen end up being activated either to open or close
Maximum/minimum temperature – what exactly are the limits of temperature desired
Maximum/minimum humidity – What exactly are the limits of humidity desired
Gap positions – this sets the percent open or close position under different circumstances such as in early stages a winter morning to reduce thermal shock or during the summer to rack drive for greenhouse china supply better shading. The gap measures and speed of movement 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 could be closed early under high wind speed conditions
Snow detection – this can open the screen and turn on the heat when it begins to snow.
The typical system uses nylon monofilament or stainless cables to support the screen materials. The screen material can possibly 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 moves the industry leading of the screen material. Control can be either with a 
manual change or electronic controller.
Based on the above, the grower must 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.