ENOX
Electromechanical NO2 Monitor for Tunnels
The ENOX is a compact electrochemical gas sensor suitable for continuous monitoring of Nitrogen Dioxide (NO2) within tunnel environments.

ENOX
The ENOX tunnel monitor measures the concentration of Nitrogen Dioxide (NO2) within an ambient environment such as road and rail tunnels or other industrial applications. These measurements can be used as part of an air quality management system for ventilation control.
The ENOX is a fixed sensor, which uses an electrochemical cell for NO2 detection. The ENOX consists of a Sender Unit and a ‘plug-in’ Sensor Module, which are mounted together on the wall or ceiling of the tunnel. The Sensor Module is pre-calibrated and stores all necessary data relating to type identification, sensing range and specific calibration. This data is automatically recognised by the Sender Unit when the module is fitted.

Features
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Designed for in-situ monitoring in tunnels or similar confined spaces
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Electrochemical measurement of NO2
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High accuracy intelligent gas detector with pre-calibrated sensing modules
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Backlit LCD display providing clear information and diagnostic data
Benefits
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Cost effective fixed sensor solution
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Rugged and reliable, with IP65 ingress protection
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Easy to install, commission and operate
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Plug-in sensor modules for quick and simple replacement
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Compatible with BS EN 50545-1:2011
Specifications
Measurement Performance
No. | Parameter | Units | Min | Max | Comment |
---|---|---|---|---|---|
1 | Measurement Range | ppm | 0 | 10 | |
2 | Resolution | ppm | 0.1 | Display resolution | |
3 | Accuracy |
ppm % |
-0.1 -2 |
+0.1 +2 | |
4 | Response Time | seconds |
40 20 |
T90 T63 | |
5 | Temperature Stability | % | -3 | +3 | Over full temperature range |
6 | Span Drift |
% / Month | -1 | +1 | |
7 | Calibration Interval | Months | 6 | 12 | Recalibrate or replace sensor module |
Power
No. | Parameter | Units | Min | Max | Comment |
---|---|---|---|---|---|
8 | Voltage | Vdc | +24 | 90-260 Vac with optional PSU | |
9 | Voltage Tolerance | % | -10 | +10 | |
10 | Nominal Current Consumption | mA | 40 | ||
11 | Power Up Current Consumption | mA | 50 |
Interface Options
No. | Parameter | Units | Min | Max | Comment |
---|---|---|---|---|---|
12 | Analogue Output | mA | 4 | 20 | (ESU-420 only) |
13 | Serial Output | Modbus RTU via RS485 (ESU-485 only) |
Physical
No. | Parameter | Units | Min | Max | Comment |
---|---|---|---|---|---|
14 | Ingress Protection | IP65 | Gas port IP54 | ||
15 | Operating Temperature | °C | -20 | +50 | |
16 | Operating Humidity | % | 15 | 90 | Non condensing |
17 | Ambient Pressure | mBar | 800 | 1100 | |
18 | Regulatory Compliance |
2014/30/EU (Electromagnetic Radiation) 2014/35/EU (Low Voltage) 94/9/EC (ATEX) | |||
19 | Materials | Reinforced Polymer | |||
20 | Dimensions | mm | 140 x 98 x 57 | ||
21 | Weight | kg | 0.6 | ||
22 | Warranty | Months | 24 | Return to base warranty. Extensions available |
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