What is the purpose of the chemical purge option on the HUMICAP sensor?

In some applications the sensor gain may decrease gradually due to an interference caused by a particular chemical present in the measured gas. The sensor polymer absorbs the interfering chemical and this reduces the ability of the polymer to absorb water molecules; consequently the sensor gain decreases. In chemical purge the humidity sensor is heated to a temperature of approximately +160 °C for several minutes, which evaporates the interfering chemical. The chemical purge cycle takes approximately 6 minutes.