In smaller sized greenhouses, a manual system opened and closed yourself could be installed. These work simplest when the screen material is supported by a track system.
Start time – when in the morning will the screen system start operation
Stop time – when in the afternoon will the screen system stop operation
Light level – at what light intensity will the screen become activated either to open or close
Maximum/minimum temperature – what are the limitations of temperature desired
Maximum/minimum humidity – What exactly 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 early morning to reduce thermal shock or during the summer to rack drive for greenhouse china provide better shading. The gap steps and speed of movement can be controlled in some systems.
Time delay – under changeable climate this avoids frequent opening and closing
Wind speed – To lessen high temperature loss, the screen could be closed early below high wind speed conditions
Snow detection – this can open the screen and turn on heat when it begins to snow.
The typical system uses nylon monofilament or stainless steel cables to aid the screen materials. The screen material can possibly 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 movements the leading edge of the screen materials. Control is definitely either with a manual switch or electronic controller.
Based on the above, the grower is required to enter the following parameters into the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.