Description	Visibility sensor for measuring K-values in tunnels
Measured values	Visibility (K-value), CO, NO, NO2
Measurement principles	Scattered light forward, electrochemical cell
Measuring ranges Visibility (K-value) 0 ... 15 km⁻¹ CO 0 ... 300 ppm NO 0 ... 100 ppm NO2 0 ... 5 ppm
Response time (t90)	≤ 60 s
Accuracy CO (0 ... 200 ppm) ≤ 1 ppm For 0 ... 30 ppm CO (0 ... 200 ppm) ≤ 1 % Of measuring range full scale (according EN 50545). For 30 ... 100 ppm CO (0 ... 200 ppm) ≤ 2 % Of measuring range full scale (according EN 50545). For 100 ... 200 ppm NO ≤ 3 % Of measuring range full scale (according EN 50545) NO2 ≤ 2 % Of measuring range full scale (according EN 50545) CO (0 ... 300 ppm) ≤ 1 ppm For 0 ... 30 ppm CO (0 ... 300 ppm) ≤ 1 % Of measuring range full scale (according EN 50545). For 30 ... 150 ppm CO (0 ... 300 ppm) ≤ 2 % Of measuring range full scale (according EN 50545). For 150 ... 300 ppm
Resolution Visibility (K-value) ± 0.001 km⁻¹ CO ± 0.5 ppm NO ± 0.5 ppm NO2 ± 0.05 ppm
Repeatability Visibility (K-value) ≤ 2 %
Ambient temperature –20 °C ... +55 °C
Storage temperature Measuring device without electrochemical cells –30 °C ... +85 °C CO, NO and NO2 sensor +5 °C ... +20 °C
Ambient pressure 860 hPa ... 1,080 hPa
Ambient humidity 10 % ... 100 % Relative humidity; non-condensing
Conformities	ASTRA "Guideline - Ventilation of Road Tunnels" (2008) RABT 2006 RVS 09.02.22
Electrical safety	CE
Enclosure rating IP6K9K
Analog outputs	3 outputs: 4 ... 20 mA, 500 Ω Electrically isolated; short-circuit proof
Digital outputs	2 relay contacts: 48 V, 0.5 mA, 24 W Preset for failure and maintenance request
Modbus ✔ Remark Not available when a TAD is used Type of fieldbus integration RTU RS-485
PROFIBUS DP ✔ Type of fieldbus integration RS-485
Indication LC display, inside Status LEDs: “Operational”, “Maintenance required”, and “Fault”
Input	Functional keys
Operation	Via LC-display and function keys
Dimensions (W x H x D) 266 mm x 159 mm x 117 mm (for details see dimensional drawings)
Weight ≤ 2.8 kg
Material	Stainless steel 1.4571
Mounting	Wall-mounting, vertical, up to a wall inclination of 45°
Energy supply Voltage 18 V DC ... 28 V DC, ± 10 % Other voltages with optional connecting unit or TAD control unit Current consumption ≤ 1 A Power consumption Without heating: ≤ 5 W With heating: ≤ 20 W
Test functions	Contamination monitoring of glass pane Drift and plausibility check Automatic self-test Functional monitoring of the optional heating
Options	CO sensor NO sensor NO2 sensor TAD control unit Connection unit

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