In smaller greenhouses, a manual system opened and closed yourself could be installed. These work simplest when the screen materials is supported by a monitor system.
Start time – when each morning will the display system start operation
Stop time – when in the afternoon will the display screen system stop operation
Light level – at what light intensity will the screen end up being activated either to open or close
Maximum/minimum temperature – what are the limitations of 
temperature desired
Maximum/minimum humidity – What are the limits of humidity desired
Gap positions – this models the percent open up or close position under different circumstances such as early on a winter morning to lessen thermal shock or during the summer to provide better shading. The gap measures and speed of movement can be controlled in a few systems.
Time delay – under changeable weather conditions this avoids frequent starting and closing
Wind speed – To reduce temperature loss, the screen can be closed early below high wind speed conditions
Snow detection – this may open the screen and turn on heat when it starts to snow.
The typical system uses nylon rack drive for greenhouse china monofilament or stainless cables to support the screen material. The screen material can possibly 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 moves the leading edge of the screen material. Control is certainly either with a manual change or electronic controller.
Based on the over, the grower must enter the next parameters in to the controller:
A climate station is required to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.