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EsiWelma Srl 

URD20SL_en.doc - rev. 0 

CO

2

 gas detectors – URD20SL 

24/09/2010 

Gas detection systems for industrial environments 

6/8

 

 

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 1

nd

 THRESHOLD relay 

NC or NO contact of 2

nd

 THRESHOLD relay 

NC or NO contact of FAIL relay 

 

DL1 (yellow),   Sensor FAIL 

DL2 (red),  2

nd

 alarm THRESHOLD 

DL3 (red),  1

st

 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 CO

2

; 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. 

1

st

 ALARM THRESHOLD 

3 flashes about every 5 sec. 

2

nd

 ALARM THRESHOLD 

4...20mA 

0,10,20mA for 

threshold 

applications 

4 flashes about every 5 sec. 

SENSOR FAIL 

22mA 

Steady 

  D   |   

  B   |   

 

1   2   

ON 

1   2   

Summary of Contents for Sensigas URD20SL

Page 1: ...n dioxide leaks or emissions in industrial environments hospitals fermentation plants greenhouses stables and more in general where carbon dioxide is stored generated or produced URD20SL sensors can b...

Page 2: ...d resistor up to 200 at 12Vdc power supply 200 700 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...

Page 3: ...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 sp...

Page 4: ...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 wi...

Page 5: ...ns 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 Connectio...

Page 6: ...cal 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...

Page 7: ...o 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 connec...

Page 8: ...or industrial environments 8 8 Installation data To be filled in by Installer Installer s stamp and signature Installation site Product order number Part Number Manufacturing date Installation date Re...

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