Several gases can be measured simultaneously thanks to the UV spectroscopy method by using different wavelengths and algorithms. For gases with a periodic absorption spectrum such as NH3, SO2, NO, CS2, formaldehyde or acetylene, an algorithm based on FFT (Fast Fourier Transform) guarantees a very good selectivity of measurement. The solid-state design due to the UV spectroscopy gives a high reliability of the measuring system with quite no maintenance.
The UV lamp is a xenon flash lamp with a high lifetime and without thermal effect that may generate measurement drift.
The gas flow cell has two quartz windows to transmit the UV light through the measured gas. The standard path length of the flow cell is 240 mm.
The spectrograph is based on a concave grating to minimize the optical parts and the spectrum is read on a 254 or 512 pixels diode array.
A zero is done automatically on zero air or nitrogen with an adjustable period (if possible every 2 or 4 hours but once per day remains acceptable).
The absorbance spectrum is calculated from the reference spectrum acquired during the zero step.

PARAMETER	RANGE* (PPM)	RANGE* (MG/M3)	TYPICAL REPEATABILITY	DETECTION LIMIT
NH3 Ammonia	0-10 ppm 0-100 ppm 0-1000 ppm	0 – 7 mg/m3 0 – 70 mg/m3 0 – 700 mg/m3	0.05 ppm at 10 ppm 0.1 ppm at 100 ppm 0.5 ppm at 1000 ppm	0.1 ppm
NO Nitrogen Oxide	0-2000 ppm	0 – 2500 mg/m3	1 ppm at 1000 ppm	3 ppm
SO2 Sulfur Dioxide	0-1000 ppm	0 – 3000 mg/m3	2 ppm at 1000 ppm	0.5 ppm
H2S Hydrogen Sulfide	0-500 ppm	0 – 750 mg/m3	0.5 ppm at 500 ppm	0.5 ppm
NO2 Nitrogen Dioxide	0-2000 ppm	0 – 4000 mg/m3		10 ppm
CS2 Carbon Disulfide	0-100 ppm	0 – 300 mg/m3
C6H6 Benzene	0-100 ppm	0 – 300 mg/m3
C7H8 Toluene	0-30 ppm	0 – 100 mg/m3
C8H10 Xylene	0-30 ppm	0 – 150 mg/m3
NCL3 Nitrogen Trichloride	0-100 ppm	0 – 500 mg/m3

Data storage	5000 measurements for all parameters
Interfaces	Interface RS232 (MODBUS, AK and http / html5 protocol) USB port (for memory stick) Internal WIFI interface IEEE 802.11 B (OPTION) Internal Ethernet 10 BASE-T interface IEEE 802.3 (option)
Signals	1 to 8 analog outputs 4-20 mA opto-isolated (option) 1 to 4 relay contacts programmable (option)
Display	LCD colour screen (TFT) with LED backlight 320×240 pixels
Power supply	110-240 VAC/ 1000 VA / 50-60 Hz
Operatings limits	0 to 40 °C, less than 90% as relative humidity
CE standards	Electromagnetic compatibility and safety EN 61010-1, IEC 61010-1 / EN 61326, IEC 61326
Enclosure	Rack 19″ 3U, coated steel
Dimensions	Rack 19″ 3U (LxlxH : 560mm x 435mm x 132 mm )
Weight	22 kg
Sampling gas	Pressure : 0 – 2 Bar Absolute (0 – 2000 hPa Absolute) Flow : 0.1 to 10 l/min Temperature : ambiant to 400 C Fittings : Swagelok, stainless steel 316 for tube OD ¼” (6.4 mm)
Zero gas	Pressure : 0 – 2 Bar Absolute (0 – 2000 hPa Absolute) Flow : 0.1 to 10 l/min Fittings : Swagelok, stainless steel 316 for tube OD ¼” (6.4 mm)

EXM400 ONLINE GAS ANALYSER