CODEL TunnelTech 100 Series User manual

Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
TECHNICAL MANUAL
TunnelTech 100 Series
TunnelTech 101
Visibility & Cold Smoke Detection
CODEL International Ltd.
Station Building, Station Road, Bakewell, Derbyshire DE45 1GE United Kingdom
t : [phone] f : [phone] e : c[email protected] web : www.codel.co.uk

CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
CODEL International Ltd is a UK company based
in the heart of the Peak District National Park at
Bakewell, Derbyshire. The company specialises
in the design and manufacture of high-technology
instrumentation for the monitoring of combustion
processes and atmospheric pollutant emissions.
The constant search for new products and
existing product improvement keeps CODEL one
step ahead. With a simple strategy, to design
well-engineered, rugged, reliable equipment,
capable of continuous operation over long
periods with minimal maintenance, CODEL has
set standards both for itself and for the rest of the
industry.
All development and design work is carried out
‘in-house’ by experienced engineers using proven
state-of-the-art CAD and software development
techniques, while stringent assembly and test
procedures ensure that the highest standards of
product quality, synonymous with the CODEL
name, are maintained.
High priority is placed upon customer support.
CODEL’s dedicated team of field and service
engineers will assist with any application problem
to ensure that the best possible use is derived
from investment in CODEL quality products.
If you require any further information about
CODEL or its products, please contact us using
one of the numbers below or alternatively visit our
web site.
t : [phone]
f : [phone]
e : [email protected]
web : www.codel.co.uk
CODEL offices, Bakewell, Derbyshire
Over the past 15 years CODEL tunnel sensors
have been supplied to more than 400 road and
rail tunnels throughout the world. Our impressive
reference list includes Eurotunnel (France), Mont
Blanc Tunnel (France), Dartford Tunnel (UK),
Lane Cove Tunnel (Australia), Snow Mountain
Tunnel (Taiwan) and the SMART Tunnel in
Malaysia, plus many others throughout China,
Italy, Switzerland and South Korea placing
CODEL as a world leader in tunnel atmosphere
monitoring.
CODEL’s tunnel sensor range is further extended
by additional sensors for the measurement of
CO, NO, Visibility and Wind Speed and Direction.
Additional product data sheets: TunnelTech 200
Series Air Quality Monitors for the Measurement
of Carbon Monoxide, Nitric Oxide & Visibility &
TunnelTech 300 Series Air Flow Monitor for the
Measurement of Wind Speed & Direction, are
available to download from our web site:
www.codel.co.uk.

Technical Manual CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190

Technical Manual CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
Contents
1. System Description 1
1.1. Air Quality Monitor –Visibility & Cold Smoke Detection 1
1.2. Measurement Elements 2
1.3. LED Control 2
1.4. Detector Element 2
1.5. Diagnostic Data 2
1.6. Calibration 2
1.7. Auto Zero 3
1.8. Temperature Measurement 3
2. Principles of Operation 4
2.1.Visibility Coefficient 4
2.2. Meteorological Visibility 4
3. Specifications 5
3.1.General 5
3.2.Visibility Measurement 5
3.3.RS485 Interface 6
3.4.Modbus Protocol 6
4. Installation 7
4.1. Mounting Details 7
4.2. Connections 8
4.3. Alignment of AQM Sensor 10
5. Commissioning 14
5.1.Alignment 14
5.2.Power Up 14
5.3.Calibration 14
5.4.Milliamp Output 14
5.5.RS485 Modbus 14

Technical Manual CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
6. Data Communication 15
6.1. Hardware Configuration 15
6.2. Address Numbers 15
7. List of Figures 16
Appendix A 17
Appendix B 19
Appendix C 21
Appendix D 24

Technical Manual CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
IMPORTANT
The warning signs (and meanings) shown below, are used throughout these instructions and are intended to
ensure your safety while carrying out installation, operation and maintenance procedures. Please read these
instructions fully before proceeding.
Caution, risk of electric shock.
Caution, risk of danger.
Caution, hot surface.
Earth (ground) terminal.
Protective conductor terminal

Technical Manual Page 1 CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
1. System Description
1.1. TunnelTech 101 –Visibility measurement and Cold Smoke Detection
The TunnelTech 101 system shown in Figure 1 uses visible light channels to measure visibility. The system
consists of a transmitter and receiver, the transmitter projects a visible beam to a detector unit mounted 6m
away in the receiver. The specific absorption at the light transmitted over the 6m path is measured to determine
the visibility dimming coefficient within the path of the beam. A high-powered modulated LED is used for the
visible light source.
Figure 1: TunnelTech 101 –air quality monitor for visibility measurement and cold smoke detection.
6m
Receiver
Transmitter
Adjustable Mounts
Temperature Sensor

Technical Manual Page 2 CODEL
Issue : A
Rev. :
Date : 29/06/2015
Ref. : 100190
1.2. Measurement Elements
The visibility sensor produces a beam of light from a pulsed LED focused by a lens to a receiver unit mounted
6m away. An internal detector within the transmitter monitors the brightness of the emitted pulses of light. The
transmitted beam is gathered by the receiver unit lens and focussed onto a receiving detector. The ratio of
signals from the two detectors provides the measurement of transmissivity.
1.3. LED Control
Operation of the emitting LED is controlled by the on-board processor. A continuous series of pulses is applied
to the LED. Each pulse is less than 100µsec in duration. These very brief duration pulses enable the instrument
to operate without interference from other light sources within the tunnel.
1.4. Detector Element
Two silicon detectors are utilised one to measure the initial brightness of the emitted light (Vis Tx), the other to
measure the intensity of the received light (Vis Rx) after transmission to the receiver unit.
The processor takes a series of measurements immediately prior to 'pulsing' the emitter LED in order to monitor
the inherent background levels of light intensity. Then a series of measurements is made while the LED is
illuminated and again after the LED is switched to check that the background levels haven’t changed. The high
frequency at which this occurs provides the device with extremely high immunity from the effects of background
lighting.
1.5. Diagnostic Data
Measurements of transmissivity and opacity are calculated from the two detector measurements. First the
detector measurements are smoothed to improve signal to noise and calculations made as follows:
Transmissivity = (Set Cal Vis) Vis Rx/Vis Tx
Set Cal Vis is the calibration constant to set the measurement of transmissivity to 100% in a clear environment.
opacity = 100 –transmissivity %
Opacity is a direct reading of the attenuation of light. Zero opacity equates to a totally clean light path and 100%
to total light attenuation.
In order to be able to resolve to a precision of 0.01%, opacity is redefined as:
opacity = 10000 –(Set Cal Vis) Vis Rx/Vis Tx
and to ensure a ‘live’ zero the opacity measurement is given an off-set of 2000. Thus:
opacity = 12000 –(Set Cal Vis) Vis Rx/Vis Tx
1.6. Calibration
It is normal for these instruments to be calibrated during a tunnel closure when it is expected that the opacity will
be zero. The instrument can be calibrated by selecting a calibrate mode where, instead of calculating opacity
using a fixed calibration factor, the instrument assumes an opacity value of zero and calculates the calibration
factor required.
Set Cal Vis = 10000 x Vis Tx/Vis Rx