In smaller sized rack drive for greenhouse china greenhouses, a manual system opened and closed yourself could possibly be installed. These work simplest when the screen materials is backed by a monitor 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 – at what light intensity will the screen become activated either to open up or close
Maximum/minimum temperature – what are the limitations of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this sets the percent open or close placement under different circumstances such as in early 
stages a winter morning to reduce thermal shock or during the summer to provide better shading. The gap actions and speed of motion can be controlled in a few systems.
Time delay – below changeable climate this avoids frequent opening and closing
Wind speed – To lessen heat loss, the screen can be closed early under high wind speed conditions
Snow detection – this can open the display and turn on the heat when it begins to snow.
The standard system uses nylon monofilament or stainless steel cables to support the screen materials. The screen material can either rest on top of the network of cables or become 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 either with a manual change or electronic controller.
Based on the over, the grower must enter the next parameters in to the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.