In smaller sized greenhouses, a manual system opened and closed yourself could possibly be installed. These work simplest when the Rack Drive For Greenhouse 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 screen system stop operation
Light level – in what light intensity will the screen become activated either to open up or close
Maximum/minimum temperature – what are the limitations of temperature desired
Maximum/minimum humidity – What are the limits of humidity desired
Gap positions – this sets the percent open or close placement under different circumstances such as in early stages a winter early morning to lessen thermal shock or through the summer to provide better shading. The gap steps and speed of movement can be controlled in some systems.
Time delay – below changeable climate this avoids frequent starting and closing
Wind speed – To reduce heat loss, the screen can be closed early under high wind speed conditions
Snow detection – this may open the screen and turn on the heat when it starts to snow.
The typical system uses nylon monofilament or stainless steel cables to aid the screen materials. The screen material can either 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 moves the industry leading of the screen material. Control can be either with a manual change or electronic controller.
Based on the above, the grower must enter the following parameters into the controller:
A weather station is required to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.