EsiWelma Sensigas URD20SS User manual

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Gas detectors
Carbon dioxide (CO2)
ATEX II 3G Ex nA nC d IIC T6 certified
URD20SS
11…28Vdc power supply.
Nondispersive infrared (NDIR) sensor designed for the detection of carbon dioxide
(CO2).
Up to three alarm thresholds plus sensing element fail.
LED on sensing element body to indicate operating status.
Automatic countdown of sensor life.
Use The URD20SS detectors are used to detect the presence of carbon dioxide (CO2), in
areas classified as Zone 2.
It detects carbon dioxide leaks or emissions in industrial environments, hospitals,
fermentation plants, greenhouses, stables and, more in general, where carbon dioxide
is stored, generated or produced.
URD20SS sensors can be used in stand-alone mode with 4…20mA output or with an
optional voltage-free contact relay card having the following four digital outputs:
Pre-alarm, 1st alarm threshold, 2nd alarm threshold, sensor fail.
Operation If there is a gas leakage, the detector compares the measured concentration value
with the threshold limit setpoints and energises the associated relays. Information on
the measured concentration value is always at the 4…20mA output.
Ordering To order, simply state the part number: URD20SS.
For special versions, on request, please contact Customer Service.

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Technical
characteristics
Type of sensor NDIR (nondispersive infrared)
Detectable Gas Carbon dioxide (CO2)
Power supply 11÷28Vdc
Max power consumption 3.2W
Measuring range 0...20,000 ppm
Precision
± 5% full scale, ± 10% readout
Repeatability
± 5% full scale, ± 10% readout
Measurement resolution 20 ppm
Microprocessor resolution 1024 points (10 bit)
Digital filter system Kalman Filter
Watchdog Internal
Warm-up time < 2m
Stabilization time < 2m
Response time < 25s (T90)
Average Sensor life (in air) 255 weeks
4..20mA Output
Proportional mode
(default)
Consumption mode
(applications at 1 or 2
thresholds)
4…20mA Output reference
selection:
- 4mA = 0 ppm
- 20mA = 20000 ppm
- 0mA = no alarm
- 10mA = 1st threshold alarm
- 20mA = 2nd threshold alarm
by jumper selectable polarity
4…20mA output load resistor - up to 200
Ω at 12Vdc power supply
- 200
Ω ÷ 700 Ω at 24Vdc power supply
Operating Temperature
Storage Temperature -20 ÷50 °C
-20 ÷70 °C
Relative Humidity (without condensing)
- Operation
- Storage
15 ÷90 %RH
45 ÷75 %RH
Operating pressure (KPa) 80
÷ 110
Air speed (m/s)
≤ 6
Visual warnings Red LED visible with detector energised
Dimensions and weight See dedicated section
Options & Accessories
Card with 4 SPDT relays UZR20.4
NO or NC contacts available,
jumper selectable
See threshold limit settings
Maximum relay capacity: 50mA at 24Vac/dc, 100mA at 12Vac/dc
- direct: relay ON when an event is
detected
- reverse: relay ON when no event is
detected
TUL40.. Gas calibration kit
See installation and commissioning chapter
TUS40 Handheld terminal
for service and maintenance
See installation and commissioning chapter
CRG40 Gas collecting cone
See dedicated data sheet
PAP40 Powerful jets protection
See dedicated data sheet
ATEX markings
II 3G Ex nA nC d IIC T6
BVI 07 ATEX 0033
-20°C ≤ TA ≤ +50°C

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Sensors lifetime Sensor average lifetime (see technical characteristics) is referred to a typical usage
in a pollution-free environment. Presence of a high concentration of pollutants can
shorten the lifetime of the sensing element.
Once the detection system starts up, it has to be supplied with energy during all the
lifetime of its sensors.
Seasonal use of the detection system is not recommended.
Installation
The relative density of carbon dioxide is about one and a half times that of air, so it
tends to collect at floor level in closed, unventilated environments.
Therefore, the sensor must be installed about 30 cm above the floor level.
Take into consideration the following specific installation guidelines, as well as
the above instructions, for location of the detectors.
The detectors must be installed:
1. where accidental gas leakages are possible
2. at least 1.5m away from heat sources or from vent holes
3. not in spaces where ventilation is poor and where gas pockets may form
4. away from hindrances to natural gas flow
5. away from equipment that may leak gas during normal operations
6. in environments with a temperature range of -20°C to 50°C and relative
humidity below 90% (non-condensing)
7. Disconnect equipment from the power supply when mounting and
dismantling detectors.

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Electrical Installation
Terminal board and
electrical connections
Cabling:
Configuration:
4…20mA Output
reference selection:
4...20mA signal
operating mode
configuration:
Setting threshold limit
values:
CAUTION: Make the area safe and make sure that the device power supply is
off before cabling and configuration operations.
Install the sensor in compliance with EN 60079-14.
The cable gland provided on the housing is used for cable entry.
Ground the sensor using the internal grounding system.
Ground connection
Terminal Board TB1
+
12…24Vdc -
-
4…20mA +
JP2 jumper circuit
S1 DIP switch
Depending on the connecting distance, use at least 3-core cable, min diameter
0.75mm2up to 100mm2, 1mm2up to 200mm2, 1.5mm2up to 500mm2.
Use shielded cable where there is a risk of electromagnetic interference.
If a relay card is used, use multi-core cable suitable for the number of connections.
Default settings of the sensor are shown in the “Technical Specifications” chapter.
In order to change the default settings, switch off the power supply, input the new
settings at the JP2 jumper circuit or at the S1 DIP switch as shown in the diagram,
then power-up again; in particular:
The default setting for the 4-20mA signal is the negative power signal. Output
reference selection should be made by JP2 triple of jumpers; to change this setting,
operator has to move JP2 jumpers as shown in the figure:
Caution: if the default settings are changed,
the connections on the TB1 terminal board
will be inverted.
Ref. at - (default) Ref. at
To set the operating mode of the 4...20mA signal, it is necessary to use the 5th
selector of the DIP switch at S1; in particular:
Proportional Threshold mode
To set the threshold limit values of the optional relay card, or of the threshold
operating mode of the 4...20mA signal, it is necessary to use the first four selectors
of the DIP switch at S1; in particular, the thresholds, given in full scale percentage,
will be:
Sensor
card
(*) When the first four selectors
of the DIP switch are in OFF
position, the threshold limit
values can only be set by the
TUS40 handheld terminal.
If this is selected without using
the handheld terminal, the
detector will automatically se
t
the default threshold limi
t
values. To set the detecto
r
with the handheld terminal, see
the dedicated instruction
manual.
Relay card
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
CN4 connection for handheld
terminal
Connection slot
for relay card
CUSTOM
(
*
)
3
,
5
,
10% 5
,
10
,
15% 5
,
10
,
20% 10
,
15
,
25% 10
,
15
,
30%
10, 20, 40% 10, 25, 35% 15, 25, 40% 15, 30, 45% 25, 35, 50% 20, 40, 60%
(DEFAULT)
20
,
40
,
80% -----------------Future im
p
lementations------------------
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
CU
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON

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Mechanical installation
of the optional relay
card
The control card can be expanded with a relay card inserted into a dedicated
connector CN3 with four SPDT relays that will be activated under the following
conditions: pre-alarm, 1st threshold alarm 2nd threshold alarm and sensor fail, and
relative LED alerts.
To install the card, follow the instructions below:
Step 1:
Insert the connection slot provided
with the relay card into the control
card, making sure the flexible tab is
towards the main terminal board.
Find CN3 connector.
CN3 connector
Connection slot
(flexible tab)
Step 2:
Fit the relay card snugly
and pull the flexible tab
of the connection slot
towards the main
terminal terminal board.
Flexible tab
Step 3:
Check the position of the card. Make sure
that all the card pins fit into the CN3
connector and push slightly upwards to
check that the flexible tab on the connection
slot keeps the card in place.
Step 4:
Tick the check box with a
permanent marker to
indicate the presence of
the relay card in the device
TYPE URD20SS

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Electrical installation of
the optional relay card
Selecting the type of
contact on the terminal
board:
Configuring the relay
operating mode:
After mechanically installing the relay card, it is necessary to configure it electrically,
selecting the relay operating mode and the type of contact desired on the terminal
board (NC or NO).
A pair of extractable terminals is available for each relay; the type of contact (NC or
NO) to be associated with them can be selected using the JP1…JP4 jumpers.
NC or NO contact of pre-alarm relay
NC or NO contact of 1nd THRESHOLD relay
NC or NO contact of 2nd THRESHOLD relay
NC or NO contact of FAIL relay
DL1 (yellow), Sensor FAIL
DL2 (red), 2nd alarm THRESHOLD
DL3 (red), 1st alarm THRESHOLD
DL4 (red), Pre-alarm
Selecting the terminal contact:
NC NO
To set the operating mode of the relays: for direct (relay energised by event) or
reverse (relay energised with no event), it is necessary to use the 6th selector of the
DIP switch at S1; in particular:
direct operating mode reverse operating mode
Checklist after
mechanical and
electrical installation
The sensors are factory calibrated so they normally do not require any other
calibration once installed. Still, after installation, an operational check of the sensors
is recommended.
The detector will enter a 2-minute warm-up phase after power-up.
After this time, the sensor will switch to normal operating mode, but it will take about
2 hours before it reaches top performance level.
When the detector is operating, a gas response check should be carried out using
the TUL40.. gas calibration kit. This kit contains:
- 2 calibration gas cylinder: 1 x 5000ppm of CO2; 1 x Pure Nitrogen
(see kit part numbers on the specific technical data sheet)
- pressure valve and flow regulator
- sensor body adapter
- about 2 metres of hose between cylinder and adapter.
During the test, check the output current, the status of the LED outside the
enclosure on the sensor body and, if present, the status of the LEDs on the relay
card before closing the housing.
The LED on the sensor body and the 4...20mA output have the following operating
meaning:
Sensor status 4...20mA Output Status LED on sensor body
WARM-UP 2mA Flashing at 2Hz frequency
OPERATING 1 flash about every 10 sec.
PRE-ALARM 2 flashes about every 5 sec.
1st ALARM THRESHOLD 3 flashes about every 5 sec.
2nd ALARM THRESHOLD
4...20mA
0,10,20mA for
threshold
applications
4 flashes about every 5 sec.
SENSOR FAIL 22mA Steady
D | C
B | A
ON
1 2
ON

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Checklist after
mechanical and
electrical installation
(continued)
Use the calibration kit to apply the gas mixture at 5000ppm of CO2, making sure
that the 4...20mA output is between 7 and 9mA (theoretic value 8mA), and that the
status LED and the pre-alarm, 1st and 2nd alarm threshold on the optional relay card
switch on according to the threshold settings.
Use the Pure Nitrogen gas cylinder to check the zero calibration.
Maintenance
Routine
Corrective
Decommissioning
A sensor functional test should be carried out every three-six months.
Routine maintenance involves repeating the same tests as set forth in “checklist
after mechanical and electrical installation”.
If any abnormalities are found during routine sensor maintenance, return the sensor
concerned to the supplier / installer, who in turn will send it back to the
manufacturer.
Sensors may need to be re-calibrated, using the TUL40.. gas calibration kit and the
TUS40 handheld terminal, which must be connected to the sensor via the
communication interface integrated in the cable (on the connector CN4).
For the re-calibration procedure, see the instructions supplied with the handheld
terminal.
Remove power from the detector, disconnect all wiring and conduits and dismount
the housing from all the blocking systems.
Warranty
Warranty on EsiWelma products is valid for 12 months from installation date and
no longer than 24 months from manufacturing date on the product. Installation
data, stamp and signature on the data sheet filled in by the installer will be
considered proof for warranty.
A copy of the warranty data sheet must be sent when returning the product under
warranty.
Accessories UZR20.4 Four-relay card
TUL40.. Gas calibration Kit
TUS40 Handheld terminal
CRG40 Gas collecting cone
PAP40 Powerful jets protection
Dimensions and weight
Dimensions (HxWxD): 155x100x60mm. Weight: 0.65Kg

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Key to marking
information
Marking in conformity with all applicable EC Directives
Marking for all equipment in conformity with Directive 94/9/EC (ATEX)
II Equipment Group for surface industry
3 Equipment category 3 for use in Zone 2
G
Equipment intended for use in explosive gas atmosphere, caused by mixture of air
and gas, vapours, flammable mist
Ex nA nC d IIC T6
Types of protection complying with EN60079-0 and EN60079-15,
sensor body with type of protection d in compliance with EN60079-1
BVI 07 ATEX 0033 Type examination certificate
-20°C ≤TA ≤+50°C Operating temperature range
Installation data
To be filled in by Installer Installer's stamp and
signature
Installation site:
Product order number:
Part Number: Manufacturing date:
Installation date: Replacement date:
Routine checks
To be filled in by Installer / Service Personnel Signature
Remarks
……………………………………………………………………………………………………………..
……………………………………………………………………………………………………………..
……………………………………………………………………………………………………………..
……………………………………………………………………………………………………………..