In smaller sized greenhouses, a manual system opened and closed by hand could be installed. These work easiest when the screen materials is supported by a monitor system.
Start time – when in the morning will the display system start operation
Stop period – 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 are the limits of temperature desired
Maximum/minimum humidity – What are the limitations of humidity desired
Gap positions – this sets the percent open up or close placement under different circumstances such 
as early on a winter morning to reduce thermal shock or during the summer to supply better shading. The gap techniques 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 heat loss, the screen can be closed early below high wind speed conditions
Snow detection – this can open the screen and turn on the heat when it begins to snow.
The standard system uses nylon monofilament or stainless cables to aid the screen material. The screen material can possibly rest on top of the network of cables or end up being 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 is usually either with a manual switch or electronic controller.
Based on the above, the grower must enter the next Rack Drive For Greenhouse parameters into the controller:
A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.