In smaller greenhouses, a manual system 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 screen system start operation
Stop period – 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 up or close
Maximum/minimum temperature – what are the limits of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this units the percent open up or close placement under different circumstances such as early on a winter early morning to reduce thermal shock or during the summer to supply better shading. The gap actions and speed of movement can be controlled in some systems.
Time delay – under changeable climate this avoids frequent starting and closing
Wind speed – To reduce temperature loss, the screen could be closed early under high wind speed conditions
Snow detection – this may open the screen and turn on heat when it starts 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 end up being suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that techniques the industry leading of the screen materials. Control can be either with a manual change or electronic Rack Drive For Greenhouse controller.
Based on the above, the grower is required to enter the next parameters into the controller:
A weather station is required to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.