In smaller greenhouses, a manual system opened and closed yourself could be installed. These work easiest when the screen material 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 screen system stop operation
Light level – at 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 pieces the percent open or close position under different circumstances such as early on a winter morning to lessen thermal shock or through the summer to provide better shading. The gap measures and speed of movement can be controlled in some systems.
Time delay – below changeable weather conditions this avoids frequent Rack Drive For Greenhouse opening and closing
Wind speed – To lessen heat loss, the screen could be closed early under high wind speed conditions
Snow detection – this can open the display 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 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 following parameters in to the controller:

A weather station is needed to provide outdoor light level, temperature, humidity, wind and rain or snow conditions.