In smaller sized greenhouses, a manual rack drive for greenhouse china system opened and closed yourself could be installed. These work easiest when the screen material is backed 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 be activated either to open up or close
Maximum/minimum temperature – what are the limitations of temperature desired
Maximum/minimum humidity – What exactly are the limitations of humidity desired
Gap positions – this sets the percent open or close position under different conditions such as in early stages a winter early morning to lessen thermal shock or during the summer to provide better shading. The gap steps and speed of motion can be controlled in some systems.
Time delay – under changeable weather conditions this avoids frequent starting and closing
Wind speed – To reduce warmth loss, the screen can be closed early below high wind speed conditions
Snow detection – this can open the display screen and turn on 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 possibly rest on top of the network of cables or be suspended by hooks from the cables. A gearmotor powers a drum or rack and pinion that moves the leading edge of the screen material. Control is certainly either with a manual switch or electronic controller.
Based on the above, the grower must enter the next parameters into the controller:
A climate station is required to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.