In smaller greenhouses, a manual system opened and closed by hand could be installed. These work easiest when the screen material is backed by a monitor system.
Start time – when each morning will the display system start operation
Stop time – when in the afternoon will the display screen system stop operation
Light level – at what light intensity will the screen be activated either to open or close
Maximum/minimum temperature – what exactly are the limits of temperature desired
Maximum/minimum humidity – What exactly are the limits of humidity desired
Gap positions – this units the percent open or close position under different conditions such as early on a winter morning to lessen thermal shock or during the summer to provide better shading. The gap techniques and speed of motion can be controlled in some systems.
Time delay – below changeable climate this avoids frequent opening and closing
Wind speed – To lessen heat loss, the screen could be closed early below high wind speed conditions
Snow detection – this can open the screen and turn on the heat when it starts to snow.
The standard system uses nylon monofilament or stainless steel cables to aid the screen material. The screen material can possibly rest along with the network of cables or end up being suspended by hooks from the cables. A Rack Drive For Greenhouse gearmotor powers a drum or rack and pinion that movements the leading edge of the screen material. Control can be either with a manual change or electronic controller.
Based on the over, the grower must enter the next parameters into the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.