In smaller greenhouses, a manual program opened and closed by hand could possibly be installed. 
These work easiest when the screen material is supported by a track system.
Start time – when in the morning will the display screen system start operation
Stop time – when in the afternoon will the display 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 are the limits of temperature desired
Maximum/minimum humidity – What are the limits of humidity desired
Gap positions – this units the percent open up or close placement under different circumstances such as in early stages a winter morning to reduce thermal shock or during the summer to supply better shading. The gap measures and speed of motion can be controlled in a few systems.
Time delay – below changeable climate this avoids frequent starting 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 display screen and turn on the heat when it starts to snow.
The typical system uses nylon monofilament or stainless steel cables to aid the screen material. 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 Motor Gearboxes For Greenhouse pinion that movements the industry leading of the screen materials. Control is certainly either with a manual switch or electronic controller.
Based on the above, the grower must enter the following parameters in to the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.