The measuring system consists of two external electrode tubes (1 & 2), each of which houses a centric and electrically insulated smaller electrode. Between the external and internal electrodes, a DC potential is applied, thus generating a DC electric field between the electrodes. The fan (4) continuously sucks air at a defined flow rate through both the electrode tubes. The DC electric field exerts a force in the vicinity of the electrodes on the ions in the streaming airflow (Coulomb’s law) and deflects them to the internal electrodes. Since the polarities of the applied voltage differ in both electrodes, one electrode accelerates the positively charged ions and the other electrode the negatively charged ions to the internal electrode. The flow velocity of the air, the level of the deflection voltage and the geometry of the electrodes are dimensioned such that ions from a defined ion mobility reach the internal electrode. Air ions with a lower ion mobility (medium and large ions) only partially reach the internal electrode.

At very high ohmic resistances (R) (up to 10¹¹ ohm), the charge current flowing during the charge neutralisation generates a measurable drop in voltage, which is boosted using suitable measuring amplifiers (3) to a measured-value signal proportional to the air ion concentration and then digitalised in the preliminary stage (6).
IM806 Functions

The entire sequence of operations is controlled using a microcontroller (5) which also handles the display, the storage logic, the analogue outputs (7), the serial interface and the network interface.

A temperature and humidity sensor (T/H) is also optionally available in the airflow outlet for recording the air temperature and relative humidity.

Applications
Technical data
Functional principle
Software
Option Extension tube
Option Transport case

Product overview
(Ionometer)