Function Block DEWPOINT

The Function Block DEWPOINT calculates the dew point based on temperature and relative humidity.

The dew point is the temperature at which the relative humidity is 100 %. At this threshold, dew or fog forms because the air is saturated at this temperature.

Input Temperature [°C]

The input defines the air temperature in Celsius.

Input Humidity [%]

The relative humidity for calculating the dew point. If the value is equal to or less than 0, then the value 0.001 is assumed for calculation. This avoids the error of division by zero. Values above 100 are limited.

Output

Outputs the calculated dew point [τ] according to the formula below.

τ=(234.67 * 0.434292289 * log(6.1 * exp((7.45 * t)/(234.67 + t) * 2.3025851) * φ / 100 / 6.1)) / (7.45 - 0.434292289 * log(6.1 * exp((7.45 * t) / (234.67 + t) * 2.3025851) * φ / 100 / 6.1))
τ=[Dew Point]
t=[Temperature]
φ=[Relative Humidity]