Détecteur DAX 420 Infrarouge - Dalemans Gas Detection

INFRARED
GAS DETECTOR
DAX 420
IR
DAX 420
MADE IN BELGIUM
www.dalemans.com
INSTALLATION, OPERATING AND
MAINTENANCE INSTRUCTIONS
Ver. V1R1

1
Introduction
These instructions must be read carefully by any person who has or will have the responsibility for
the installation, the use and/or the maintenance of this equipment. The warranty provided by
DALEMANS will be voided if installation, use and maintenance of this equipment are not in accordance
with the instructions given in this manual.
By respecting these instructions you guarantee the correct operation of the apparatus. Should you
require any further information about the use or the maintenance of this product, do not hesitate
to contact Dalemans PRIOR to carrying out installation works.
Each apparatus must be installed, operated and maintained according to the instructions, the
warnings and the operational limits detailed in this manual.
Use only DALEMANS original parts when you assume the maintenance of this product as specified
in this manual. The use of non-Dalemans spare parts may seriously impair the performances of the
apparatus. Repair or maintenance attempts carried out without observing the procedures
described in this manual or without the assistance of our after-sales service may prevent the
equipment from working properly and, consequently, from ensuring the safety of the occupants
of the building and of the plants.
!
Application
Always make sure to switch off power and declassify the hazardous area before
carrying out replacement or modification works on components of the gas
detection system.
The DAX 420 infrared gas detector is intended for industrial and commercial environment and is
suitable for use in explosive atmospheres of hazardous areas (zone 1 or 2). It is designed to operate
as part of a gas detection system, and to provide, in association with a suitable control unit or
with a Programmable Logic Controller (PLC), early warnings of toxic or flammable gas hazard.
For further information about the detectable gases or the list of compatible control units, please
contact Dalemans.
Approval - Standards
As a manufacturer, Dalemans Company declares that the products hereby described are certified for
hazardous areas with an ingress protection degree IP6X corresponding to non-aggressive indoor
environments, and that they fulfil the provisions of the following directives and standards :
The said products comply with the acceptable variations originating from the type that has received
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2
Marking
The label below is affixed to the junction box of the detector. This marking applies to the detector
overall assembly. The marking label affixed to the sensing head applies only to the sensing head.
Device Type
ATEX certificate number
Notified Body
identification code
Serial Nr - year of production
Target gas
Measuring range
Operating
temperature range
1026
DAX 420
II 2G Ex d IIC T6
II 2D Ex tD A21 IP6X T85°C
Tamb: -20°C to +55°C
FTZU 09 ATEX 0182
D020AAAM - 91099031 - 2010
Gas: CH4
100% LEL
Use: -20..+50°C
IR
Certification (ATEX)
II : non-mining electrical equipment group for potentially explosive atmospheres.
2G : category 2 equipment intended for use in areas where GAS explosive atmospheres
are likely to occur (zone 1).
Ex d : protection by flameproof enclosure “d”.
IIC : equipment group II subdivision according to the nature of the explosive GAS
atmosphere (methane, propane, ethylene, hydrogen, acetylene).
T6 : temperature class according to the maximum surface temperature of the equipment
in explosive GAS atmosphere (T6=85 °C).
2D : category 2 equipment intended for use in areas where DUST explosive atmospheres
are likely to occur (zone 21).
Ex tD : dust ignition protection by enclosure “tD”.
A21 : method of determining the maximum surface temperature of equipment (with 5
mm layer of dust) for use in areas where an explosive atmosphere of combustible
DUST is likely to occur, occasionally, in normal operation (method A - zone 21).
IP6X : dust tight ingress protection.
T85 °C : maximum surface temperature of the equipment for DUST explosive atmospheres.
Tamb : ambient temperature range according to the rated temperature class and the
maximum surface temperature (Tamb = -20 °C to +55 °C for T6 and T85 °C).
DAX 420
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3
Description
The DAX 420 infrared gas detector is designed to detect the presence of toxic gas or to measure
infrared
Programmable Logic Controller (PLC) through a 3-wire current loop.
The main parts of the DAX 420 infrared gas detector are :
The overall assembly has a flameproof “d” type of protection and an ingress protection IP6X.
Flameproof “d”
junction box
Terminal block
Flameproof “d”
cable gland
4..20 mA
transmitter
“Fault” LED
Wall mounting bracket
Flameproof “d”
sensing head
Figure 1 : DAX 420 infrared detector
DAX 420
IR

4
Sensing head
The infrared sensor operates according to the Non Dispersive InfraRed principle (NDIR). The sensor
comprises a sample chamber, an infrared light source (lamp) and a wavelength infrared detector.
When a gas diffuses into the sample chamber it absorbs a portion of the infrared radiation of the
lamp. The amount of infrared radiation absorbed by the gas is proportional to the gas concentration.
The wavelength infrared detector measures the unabsorbed infrared radiation and deliver an output
signal which is a function of the gas concentration in the ambient air.
The sensing head of the DAX 420 infrared consists of :
The sensor housing is a stainless steel assembly (body and top) which can be dismantled to allow
plug-in sensor or sintered metal filter replacement.
Top
Sensor sleeve
Sintered metal
filter
Infrared sensor
Body
Figure 2 : Sensing head
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5
Dimensions
65
145
60
8
65
DAX 420
MADE IN BELGIUM
170
www.dalemans.com
105
115
Figure 3 : Mechanical pattern
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6
Caution
Ensure that local or national regulations relating to the site or the monitored plant are met. The
operator must have knowledge of the safety procedure to follow in case of gas alarm.
Modification, disassembling and total or partial destruction of the sensing head and its contents,
of the cable gland or of the junction box and its contents, may invalidate the essential safety
requirements of the whole plant. No additional drilling is allowed on the junction box. The existing
openings cannot be enlarged. No additional terminal can be installed on the existing terminal
block. The length of the wires of the sensing head may not be modified. Possible defective parts
must be replaced by original parts delivered by Dalemans only.
Do not open the junction box or the sensing head while explosion hazard might be present. Only
clean or wipe the detector surface with a wet cloth so as to avoid the risk of electrostatic sparks.
The detector must be protected from any risk of mechanical impact.
Flammable limits and setpoints
of flammable limits. Examples include :
H
2
H 6
2
H
5
H 12
3
H
The LEL of a gas is affected by temperature and pressure. When the ambient temperature increases,
the LEL decreases and the explosion hazard is higher. The relationship between LEL and pressure is
very complex. However, a pressure increase usually lowers the LEL. The LEL of a gas is not significantly
affected by the humidity fluctuations that may normally occur in the average industrial
environment.
Installation and commissioning
Installation and commissioning must be carried out by the manufacturer or his local representative.
All the operations described hereafter can be carried out only by specialized personnel who
will have been trained beforehand exclusively by Dalemans.
Gas detection equipment should be installed as late as possible in any program of construction
operations (i.e. construction of a new plant, refitting or maintenance) but before the presence of gas
or vapours in the system, so as to avoid damage to sensors resulting in particular from such activities
as welding and painting. If already installed, sensors should be protected by an airtight seal to avoid
contamination during construction works, and should be clearly marked as being non-operational.
Please follow the recommendations hereafter so as to avoid premature ageing of the detector and
to guarantee its optimal operation. These recommendations are general directives. Always refer
to local regulations/standards in force before proceeding with installation works (i.e. standards
the recommendations of the manufacturer.
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7
Location
Detectors must be placed so that potential gas accumulations are detected before they create a
significant hazard. Inappropriate location of a detector can nullify the effect and the integrity of
the gas detection system. The placement of the detectors should be determined in consultation
with experts having specialist knowledge of gas dispersion, with those who have knowledge of
process plant system and equipment involved, and with safety and engineering personnel. Should
you require any further guidance or assistance please contact Dalemans.
Detectors should be readily accessible to permit regular calibration, maintenance and electrical
safety inspection. It must be possible to access and fit all accessories or test equipment needed for
these operations on the detector. The location of every detector must be recorded and available to
the safety personnel. The following points should be taken into account when selecting locations to
install the gas detector :
the detector at a high level.
the detector at a low level.
Examples of placement for some flammable gases * :
Gas Formula Density (air=1) Detector(s) position
Acetylene (CH) 2
Butane C
H
Floor
Ethylene oxide C 2
H
O 1.52 Floor
Cracked gas - Ceiling
Isobutane (CH 3
) 3
CH Floor
Methane CH
Ceiling
Natural gas - Ceiling
Propane C 3
H
1.56 Floor
Propane-air - ±1.15
* This list is not exhaustive. Contact Dalemans for further information.
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Mounting
The detector should be mounted flat on a wall and according to the mechanical pattern given on
figure 3. Always use the original wall mounting bracket supplied with the detector. Attach the
detector to the wall using suitable screws and plugs. The sensing head should never be installed
pointing upwards. Make sure that dust will not block the filter and that water will not run into the
sensing head.
Electrical wiring
Wiring must comply with local regulations and standards in force and meet the electrical requirements
of the DAX 420 infrared gas detector. Dalemans recommends the use of colour coded cable
with solid wires . The acceptable cross sectional area of the cable is
the control unit/PLC. For more information about the cross sectional area of the cable and the
maximum cable length, please refer to the instruction manual of the control unit/PLC. The overall
The junction box may be earthed
through the cable shield. The cable shield must be connected to the ground at the control unit/
PLC. The cable gland must be sufficiently tightened on the cable to ensure a good sealing.
8 mm MAX
6.1 mm
-
11.7 mm
0.75 - 2.5 mm²
Other size
upon request
15 mm 100 mm
Figure 4 : Cable stripping
Cable length
The DAX 420 infrared
properly. Voltages outside this range give a failure warning on “Fault” LED (see figure 1).
The maximum acceptable cable length to connect the detector to the control unit/PLC depends on :
The table below and the graph of figure 5 give examples of maximum cable length according to the
cross sectional area of the cable and according to the supply voltage level at the control unit/PLC. For
further information please contact Dalemans.
Cable cross sectional area
Max. cable length
V+ = 20 Vdc V+ = 24 Vdc
DAX 420
IR

Maximum cable length (m)
1000
900
800
700
600
500
400
300
200
100
2.5 mm²
1.5 mm²
0.75 mm²
Operating range
9
10 15 20 25 30
Supply voltage V+ (Vdc)
Figure 5 : Max. cable length
To connect the detector :
completely turn the cover counterclockwise to unscrew it.
plugged so that the gap between insulation and the metallic edge of the terminal connection
does not exceed 1 mm distance.
+ 24 V
4..20 mA
Output
S
Plug-in connector
APC Terminal block
0 V
-
Connections for
equipotential bonding
DAX 420
IR
Figure 6 : Electrical connection

10
Connection to a Dalemans control unit
The connection of the DAX 420 infrared detector to a Dalemans control unit requires a 3-wire current
loop. Electrical connection must be made with respect to polarity between the DAX 420 infrared
detector and the control unit. For instructions about the electrical connection of the control unit, refer
to the original equipment instruction manual.
DAX 420 infrared
MIN 19 Vdc
+
-
S
V+
0 V
+
-
(+24 Vdc)
4..20 mA
Input
DALEMANS
control unit
Figure 7 : Dalemans control unit
Connection to a Programmable Logic Controller (PLC)
For instructions about the electrical connection of the PLC, please refer to the original equipment
Ensure that the polarity of the DAX 420 infrared output signal meet the polarity of the PLC input.
Put a measuring resistor on the PLC input. Choose the resistor value according to the input scale. The
resistor must have a power rating of min. 1 Watt.
Example :
R Measure =
5
0.02
= 250 ohms
DAX 420 infrared
MIN 19 Vdc
+
-
S
R Measure
V+ (24 Vdc)
0 V
0-5 V
Signal
PLC
Stabilized
power supply
0 V
MIN. 1 Watt
Figure 8 : PLC
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11
Maintenance
Regularly remove dust from the sensing head and the junction box with a wet cloth ONLY so as to
limit the risk of electrostatic sparks.
The sintered metal filter must be checked and cleaned at least once a year. If contamination of the
filter by solvent, gas or gas vapour has occurred, the sensing head must be replaced and the
inspection interval should be reduced by a factor of 2.
Gas detection equipment must be calibrated at least once a year, in some cases three or four times
a year, or even more to mitigate the loss of sensitivity of the sensor. This calibration must be
performed according to the procedure given by the manufacturer or his local representative, and
in any case by qualified personnel who will have been trained by Dalemans.
WARNING! Declassify hazardous area PRIOR to operating maintenance, calibration
or service works and check with a portable apparatus that no gas is present
in the atmosphere.
Sintered metal filter replacement
Sensing head replacement
Prior to replacing the detector sensing head, inhibit the safety function of the detector on the gas
detection system and secure any output device connected to the system to prevent unintended
actuations and false alarms.
- RED on terminal A
- BLUE on terminal P
- WHITE on terminal C
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12
Troubleshooting
The detector measure is either too high or too low :
The detector gives a null measure although gas is present in the atmosphere :
Spare parts
Instruction manual
Junction box - Ex d
Key for locking screw (1.5 mm hex key)
Screw for locking the cover of junction box
2
Sensor DIR-CO 2
Sensor DIR-B (butane)
Sensor DIR-M (methane)
Sensor DIR-P (propane)
Sensor sleeve
Sintered metal filter
Spanner for top of sensing head
Article code
DAX 420
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13
Specifications
MODEL
DAX 420 infrared
Sensing head
Sintered metal filter
Junction box
Aluminium
Dimensions / Weight
Sensor type / Signal
Adjustments
Zero and calibration by internal potentiometers
Measuring range *
Butane (C
H
)
Methane (CH
)
Propane (C 3
H
)
Carbon dioxide (CO 2
)
Resolution
Expected operating life span
Electrical characteristics
Storage temperature
Operating conditions
Temperature range
Ambient humidity
Cable cross sectional area
Max. cable length
Loop resistor
Ingress protection
IP6X (dust tight)
Cable entries
Hazardous areas
Zones 1 or 2 (gas) - Zones 21 or 22 (dust)
Equipment gas grouping
IIC (methane, propane, ethylene, hydrogen, acetylene)
Standards
II 2G Ex d IIC T6
Ambient temperature
Certificates
* Other gases upon request. Contact Dalemans for further information.
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14
Glossary
Ex d :
parts which can ignite the explosive atmosphere are placed in an enclosure which can withstand the
pressure developed during an internal explosion of an explosive mixture, and which prevents the
transmission of the explosion to the explosive atmosphere surrounding the enclosure.
Ex tD :
is based on the limitation of the maximum surface temperature of the enclosure and on the restriction
of dust ingress into the enclosure to avoid ignition of a combustible dust layer or cloud.
94/9/EC :
the laws of the member states concerning equipment and protective systems intended for use in
potentially explosive atmospheres.
EN 60079-0 : standard general requirements applying to equipment intended for use in explosive
atmospheres.
EN 60079-1 : standard applying to equipment protected by flameproof enclosure “d” and intended
for use in explosive gas atmospheres.
EN 61241-0 : standard general requirements applying to electrical apparatus intended for use in
the presence of combustible dust.
EN 61241-1 : standard applying to electrical apparatus protected by enclosure “tD” and intended
for use in the presence of combustible dust.
Environment - WEEE Directive
The crossed-out wheelie bin logo on this product indicates that you are held
to respect the regulation in force on the collection and recycling of Waste
Electrical and Electronic Equipment (WEEE).
These provisions are intended to preserve the natural resources used for
manufacturing this product and to avoid the dispersion of substances
potentially harmful for the environment and human health.
Therefore, to dispose of your end-of-life product, you MUST hand it over to a designated collection
point for the recycling of electrical and electronic Equipment. For further information about the
collection points in your area, contact your local city office.
DAX 420
IR

OFFICIAL DEALER
DALEMANS s.a.
www.dalemans.com