In smaller greenhouses, a manual program 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 screen Motor Gearboxes For Greenhouse system start operation
Stop period – when in the afternoon will the display system stop operation
Light level – in what light intensity will the screen become activated either to open up or close
Maximum/minimum temperature – what exactly are the limitations of temperature desired
Maximum/minimum humidity – What are the limits of humidity desired
Gap positions – this units the percent open or close position under different circumstances such as early on a winter morning to lessen thermal shock or during the summer to supply better shading. The gap actions and speed of movement can be controlled in some systems.
Time delay – under changeable climate this avoids frequent opening and closing
Wind speed – To lessen temperature 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 begins to snow.
The typical system uses nylon monofilament or stainless steel cables to support the screen materials. The screen material can possibly 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 movements the leading edge of the screen materials. Control is usually either with a manual change or electronic controller.

Based on the over, 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.