In smaller 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 each morning will the display screen system start operation
Stop time – when in the afternoon will the display 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 limits of temperature desired
Maximum/minimum humidity – What exactly are the limits of humidity desired
Gap positions – this sets the percent open or close position under different conditions such as early on a winter early morning to rack drive for greenhouse china reduce thermal shock or through the summer to supply better shading. The gap actions and speed of movement can be controlled in a few systems.
Time delay – under changeable weather conditions this avoids frequent starting and closing
Wind speed – To lessen warmth loss, the screen could be closed early under high wind speed conditions
Snow detection – this can open the display and turn on heat when it begins to snow.
The standard system uses nylon monofilament or stainless steel cables to support the screen material. The screen material can either rest along with the network of cables or be suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that techniques the leading edge of the screen materials. Control can be either with a manual switch or electronic controller.
Based on the above, the grower must 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.