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
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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
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Technical Manual CODEL
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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

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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
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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

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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

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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

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1.7. Auto Zero
The measurement of opacity is dependent upon the optical surfaces of the instrument remaining clean. If the
surfaces of the instrument lenses become contaminated it will reduce the intensity of the received light and
increase the opacity measured value. Over a period of time, it is normal to observe a slow build-up of optical
contamination resulting in a steady increase in the measured opacity value. This appears as a persistent
positive output drift.
There are two cures for this problem. One is to clean the optical surfaces on a regular basis. However, in a road
tunnel regular access is not usually possible without a tunnel closure.
The second method is to automatically compensate for such a build-up of contamination. The technique used by
TunnelTech 101 relies on the assumption that there will always be periods of low real opacity during the course
of the day. These periods usually occur at night when traffic loading is low. These periods provide a reference
condition for the measurement.
During normal operation, the effect of contamination is to slowly increase the measured value of opacity. To
compensate for this the instrument is programmed to slowly reduce its measured value of opacity at a rate
faster than that at which contamination would increase.
Over a period of time, this will result in the instrument reading slightly low. However, during the periods of zero
opacity, this effect would cause the instrument to be displaying a negative opacity. Since negative opacity is an
impossible value the negative offset can be quickly rectified and the calibration corrected.
In this way periods of zero opacity, whenever they occur, are utilised to correct the calibration of the
measurement allowing long periods of operation without maintenance and the cleaning of optical lenses.
1.8.Temperature Measurement
The instrument is provided with a PT100 temperature sensor mounted on the transmitter unit, to enable a
continuous measurement of air temperature

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2. Principles of Operation
Visibility and Cold Smoke Detection both rely on the amount of light obscuration within the tunnel atmosphere
being determined. This obscuration is quantified by determining the visibility coefficient. A visibility sensor is
programmed to measure low levels of visibility coefficient and thus light obscuration experienced during normal
tunnel operation. A Cold Smoke Detector is programmed to detect the high levels of visibility and light
obscuration that would be produced by smoke emissions from a tunnel fire.
Both sensors use the same technology and principles at operation.
2.1. Visibility Coefficient
Visibility Dimming Coefficient (abbreviated to Dim K or Vis K)
Fine particles suspended in the atmosphere will scatter a beam of light so that the intensity of the beam reduces
as it passes through the air. This reduction in visibility is directly proportional to the concentration of suspended
dust particles.
The intensity of a beam of light follows the Lambert Beer law:
I= Ioe -KL
where K is a parameter known as the visibility coefficient and is proportional to the concentration of the
suspended particles and L is the path length of the beam.
I/Iois the ratio of the measured beam intensity and that of the initial intensity Ioand is known as the
transmissivity (T) of the system:
T = e -KL
Thus visibility coefficient :
K = 1 . loge1
L T
where L = 6m & T is the measured transmissivity.
A visibility sensor measures the transmissivity of a light beam from a source of known brightness over a fixed
path length to enable a value of the visibility coefficient to be deduced. The units of measurement for this
coefficient are m-1 and the typical span range would be 0 - 0.015m-1 or 0 -15(km)-1.
2.2. Meteorological Visibility
An alternative method of presenting this data is in the form of meteorological visibility. This is defined as the
distance over which the intensity of transmitted light falls to 5% of its initial value. It represents the distance over
which a person can see in a hazy or dusty environment.
In this case, I= 0.05 x Io thus T = 0.05
and since K = 1 . loge1
L T
visibility L = 1 loge20 = 2.99
K K
Thus, for a K value of 0.003, the visibility in metres is 2.99/0.003 = 1000m. Both K factor and visibility are
calculated by the sensor and are available for output.

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3. Specifications
3.1. General
Construction
- Stainless Steel 316 Ti –other grades available on request.
Safety & EMC
- shielded to comply with 2006/95/EEC
- EN61326-1:2006 & EN50270:2006
Ambient temperature
- -20oC to +50oC.
Dimensions
- Ø150mm x 81mm x 150mm
Power
- 24V DC, 20VA
3.2. Visibility Measurement
Measurement path
- 6m
Visibility measuring range (standard)
- Visibility : 0-15 x 10-3 m-1
- other ranges selectable on setup.
Air temperature
- PT100 resistance thermometer - range -20°C to +105°C
Averaging time
- 1 to 12 minutes.
Accuracy
- Visibility - ±0.2 x 10-3 m-1
- Temperature ± 0.2°C
Outputs
- analogue - 2 x 4-20mA, 200V common mode isolation - fully configurable for visibility and
temperature measurement.
- max. load 500
-logic –1x volt-free contacts SPCO, 0.5A @ 125V AC,2A @ 30V DC, 0.5A @ 100V DC
- RS485 serial interface.

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3.3. RS485 Interface
Power
- USB powered.
PC Communications
- USB port.
The serial USB RS485 interface is used as a temporary connection with the TunnelTech 101 during
commissioning and for diagnostic communications.
The operation function and operation of the interface are contained in Appendix A: Communication & RS485
Connection.
3.4. Modbus Protocol
Use the TunnelTech program to,
Edit the 7F3C file:
The numbers and locations are in hexadecimal - Location 7F3C = 00 Codel
= 01 MODBUS
- Location 7F1F =
Change only the above 2 bytes, then save and send the file to the TunnelTech AQM.
Note that the AQM will still communicate on address 255 with the TunnelTech software. This is to allow
communications if an AQM address and protocol is unknown.
Our Modbus can handle the following functions:
0x03: Read Holding Register
0x06: Pre-set Single Register
0x10: Pre-set Multiple Registers
(See Appendix A for more information)
the address the AQM is to use
as MODBUS slave (01 =
address 1, 02 = address 2, 0A
= address 10 etc, range 01 to
FE.)

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4. Installation
Be sure to observe all necessary safety precautions at all times during installation.
All cable gland entry holes are drilled and tapped M20 x 1.5 and are fitted with blanking plugs.
Cable glands are to be supplied by the customer according to the cables used during
installation.
4.1. Mounting Details
After unpacking the equipment check, using the packing list provided, that all items are present. The
TunnelTech 101 Air Quality Monitor (AQM) is carried on a pair of fabricated mounting brackets (if supplied).
4.1.1. TunnelTech 101 (AQM)
The AQM comprises a transmitter and receiver unit. Secure the AQM to the tunnel wall by the mounting-
brackets supplied using 4 x M8 bolts (by others) such that the transmitter and receiver are 6m apart. The
transmitter and receiver should be mounted horizontally and arranged as illustrated in Figure 2.
Figure 2: TunnelTech AQM –Mounting holes
Site tube
Receiver
Transmitter
Wall mounting holes
4 x ǿ9mm holes at 90° as shown on ǿ 80
PCD.
6m
Rx/Tx Cable
Site tubes are supplied and should
be bolted onto the mounting
brackets using the 3 x M6 bolts
provided.

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4.2. Connections
Wiring should only be undertaken by a qualified technician.
The following electrical schematic (Figure 3) illustrates the connections for the system. A soldered connection is
required between the cable and the corresponding plug or socket.

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Figure 3: Electrical Schematic
24V Power
Supply
Power
Rx/Tx
Cable
Plug
Plug
Current
O/P
Comms
Socket
Socket
AQM
Transmitter
No connection
+ Vout
1
5
2
- Vout
3
4
7
5
E
9
1
3
3
3
3
3
E
2
2
1
4
E
6
3
5
12
13
14
15
16
17
18
0ma
+ma
+MA
Screen earth
Contact
0MA
Contact
Sig
0V
No connection
1
2
3
E
19
20
21
22
(Tx) A
(Rx) B
No connection
No connection
1
Socket
Socket
Plug
Plug
8
+V
0V
Screen earth
6
10
11
AQM
Receiver
6
1
2
3
4
5
7
Socket
Rx/Tx
Cable
+ Vout
- Vout
1
2
E
6
5
4
3
Sig
0V
No connection
Plug
2
3
4
6
1
3
3
3
3
3
E
2
1
2
3
4
5
E
6
1
2
3
4
5
E
6
1
2
3
E
1
2
E
6
5
4
3

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4.3. Alignment of AQM Sensor
Note –Align the transmitter and receiver prior to connecting power.
The AQM transmitter and receiver units should be mounted horizontally and should be properly aligned for
optimum performance.
4.3.1 Laser Adapter Assembly
Mount the laser onto the adapter as shown in Figure 4.
Figure 4: Mounting Laser

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Fit the assembly illustrated in Figure 4 onto the transmitter site tube. Make sure the plate of the adapter and the
sight tube connect flush in the orientation shown below.

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4.3.2 Horizontal Alignment of Transmitter
4.3.2.1
Slide the laser adaptor over the sight tube so that the laser pointer is at the top of the sight tube. Ensure that the
holes in the adaptor flange locate onto the heads at the sight tube mounting bolts.
Loosen screw 1 slightly to allow movement at the bracket. Position the laser line onto the centre of the receiver
site tube then tighten screw 1, see Figure 5.
Figure 5: Horizontal Alignment
Receiver
Transmitter
Screw 1
Tunnel mounting wall
Screw 1
Transmitter
Movement direction