In smaller sized greenhouses, a manual system opened and closed yourself could possibly be Rack Drive For Greenhouse installed. These work easiest when the screen materials is backed by a track system.
Start time – when each 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 end up being activated either to open up or close
Maximum/minimum temperature – what are the limits 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 circumstances such as early on a winter early morning to lessen thermal shock or through the summer to provide better shading. The gap techniques and speed of movement can be controlled in some systems.
Time delay – below changeable weather conditions this avoids frequent opening and closing
Wind speed – To reduce heat loss, the screen could be closed early below high wind speed conditions
Snow detection – this can open the display 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 either 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 movements the leading edge of the screen material. Control can be 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.