The outside temperature is an important factor for the greenhouse climate. This is true when the vents are shut, but especially when the greenhouse is being ventilated. The outside temperature sensor is important, because its measurements allow the iSii process computer to control the heating, ventilation and energy screens. By preventing a back-and-forth between ventilation and heating, an even and energy-efficient greenhouse climate is achieved.
The sensor is set up in a special housing that ensures sufficient ventilation of the sensor and protects the measurements against influences from precipitation, direct sunlight and reflection.

The sun is by far the biggest heat source for greenhouses. In addition, the sun is a determining factor for crop evaporation and irrigation. Thus, the measurement of the overall solar radiation is very important for climate regulation. Solar radiation is measured with a pyrano, or solari, sensor. These measurements are important because they are used by the iSii process computer to control different greenhouse processes, like heating, ventilation, screens, irrigation, energy management, etc.

Wind speed is another determining factor for the greenhouse climate. Measurements of the wind speed sensor are used by the iSii process computer to optimize the regulation of e.g. air vents, heating and energy screens. Moreover, the measurements are used to limit some controls at too high wind speed. For example, the air vents can be closed when the wind speed reached a certain limit in order to protect both the greenhouse and the crop from storm damage.
To avoid freezing the wind speed sensor is equipped with a heater.

For greenhouses with air vents on both sides of the roof ridge a distinction is made between the lee side and the wind side. Depending on the wind direction, vents can be opened on the lee side, the wind side, or both sides for the best effect on the greenhouse climate. In addition to ventilation controls, many other controls can be affected by the wind direction, such as shading and irrigation.
Like the wind speed sensor, the wind direction sensor is equipped with a heater to avoid freezing.

Precipitation in the form of rain, hail, or snow has a strong influence on the greenhouse climate. On the one hand because of greater heat loss, on the other hand because the vents must be closed immediately to prevent the crop from getting wet.
The precipitation sensor detects precipitation because the sensor surface gets wet. The signal of precipitation yes or no is sent to the iSii process computer, which responds to this quickly and accurately by for example adjusting the controls for heating and closing the air vents. The sensor’s sensitivity can be adjusted, so you can decide on the precipitation intensity at which the controls must be activated. The precipitation sensor has a built-in heating element that ensures that the sensor dries quickly after a rainstorm so that normal regulation of the greenhouse climate can be resumed.

In addition to the precipitation sensor that detects the presence of precipitation, it may be useful or in some cases even necessary to measure the exact amount of precipitation per unit of time. This is done to take better account of the cooling effect of precipitation. Furthermore, a lot of precipitation in a short period of time can cause flooding.
The precipitation intensity sensor is also applicable as a snow detector.

Outside humidity has a strong influence on the greenhouse climate. When the air vents are opened, warm, damp greenhouse air is exchanged for cooler, drier outside air. To the extent that the outside air is drier, relatively more moisture is carried off at the same ventilation speed. For plants, low RH is often a more serious stress factor than a high greenhouse temperature. For this reason, low outside RH can be a reason to ventilate less, despite the fact that the greenhouse temperature increases.
Standard an electronic type of outside RH sensor is used. This special type can be used in all outside conditions, such as precipitation.

The pyrgeo sensor measures the outgoing long wave heat radiation. This is an important factor in the energy balance of plants and in the greenhouse as a whole. Under a clear sky, the energy loss by outgoing long wave radiation (OLR) is much bigger than under a cloudy sky. The measurements of the pyrgeo sensor allow the iSii process computer to adjust the control of the energy screens, for example to adapt for less or more energy loss of the greenhouse. This results in valuable energy savings and prevents from undesired cooling of the crop.