Radix offers relative-humidity (RH) controller that uses wet and dry bulb temperatures to measure and display RH. RHC301,a relative-humidity (RH) controller that uses wet and dry bulb temperatures to measure and display RH. A superior version of RHC201, it can apply a maximum or minimum function on RH as well as calculate dew point temperature. It receives two 4 - 20 mA or RTD inputs for wet and dry bulb temperatures within the range of -20 to 100 °C. The RH controller has a large two-color triple LED display to indicate a large variety of parameters. The upper display can indicate the calculated RH, peak RH (maximum) or valley RH (minimum).