The HD2717T instrument measures temperature and humidity, can act as transmitters, indicators and also regulators for the ON/OFF function besides and data logging. Without interruption of the process, the probes can be replaced. It is possible to repair the probe or have it calibrated at a later stage. The instrument has been developed in three versions: with a horizontal, a vertical, or a remote probe. A cable of various lengths connects the probe to the electronics. The horizontal and vertical probes are made of stainless steel AISI304, and the remote probe of stainless steel AISI304 or POCAN (plastic material). The factory-calibrated probe is ready to use. It has a SICRAM2 module with the calibration data. This makes the probe interchangeability possible.