In smaller sized greenhouses, a manual system opened and closed yourself could possibly be installed. These work simplest when the rack drive for greenhouse china screen materials is supported by a monitor system.
Start time – when each morning will the screen system start operation
Stop time – when in the afternoon will the screen system stop operation
Light level – at what light strength will the screen end up being activated either to open or close
Maximum/minimum temperature – what exactly are the limitations of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this units the percent open up or close position under different conditions such as early on a winter morning to lessen thermal shock or during the summer to provide better shading. The gap guidelines and speed of movement can be controlled in a few systems.
Time delay – below changeable climate this avoids frequent starting and closing
Wind speed – To reduce heat loss, the screen could 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 monofilament or stainless steel cables to aid the screen materials. The screen material can either rest along with 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 definitely either with a manual switch 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.