The Ozone meter for gases measures the ozone concentration according to standard DIN 19627 and the IOA (International Ozone Association) at a wavelength of 254nm. According to these standards, the extinction coefficient is 3024 l/mol cm. Therefore, the ozone measurement can be regarded as an absolute measurement requiring no calibration with ozone. Special measuring cells with different path-lengths cover measuring ranges for low as well as high concentrations. The concentration readings (e.g. in g/m3) are valid for the pressures and temperatures prevailing during measurement. For the conversion to standard conditions, an external pressure and temperature sensor can be connected to the operating unit, die calculation is then automatically done within the instrument. For inspecting the instrument, checking units on the basis of reference filters can easily be inserted. Operation is done intuitive using the intelligent control system SICON via touch screen technology and colour display. Values, graphs, alarm and status messages can be presented. An internal data logger allows recalling and displaying measured data from the last 32 days. A variety of analogue and digital interfaces allows smooth system integration and control.