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EW0826A2_en - rev. A 

Oxygen detectors 

 URS20SI 

05/10/2020 

Gas detection systems for industrial environments 

1/8

 

 

 

 

 

 

Sensigas

®

 

Oxygen detectors 

IP65 protection rating 

 

URS20SI 

 

 

 

 

 

 

 

 

 

Sssssss 

 

 

 

11

…28Vdc power supply. 

Electrochemical cell sensor designed for the detection of oxygen (O

2

). 

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 URS20SI detectors are used to detect oxygen excess or deficiency in non-classified 
areas. 

An

 oxygen excess

 forms if it leaks in hospitals, laboratories, welding centres and, more 

in general, where oxygen is stored. 

Oxygen deficiency

 is an indirect measurement of the presence of other explosive or 

asphyxiant 

gases that deplete the oxygen in the air. 

URS20SI 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, 1

st

 alarm threshold, 2

nd

 alarm threshold, sensor fail. 

Operation 

If there is an oxygen leak or an absence of oxygen, 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: 

URS20SI

For special versions, on request, please contact Customer Service. 

 

Summary of Contents for EsiWelma Sensigas URS20SI

Page 1: ...ore in general where oxygen is stored Oxygen deficiency is an indirect measurement of the presence of other explosive or asphyxiant gases that deplete the oxygen in the air URS20SI sensors can be used...

Page 2: ...esholds 4 20mA Output reference selection 4mA 0 O2 20mA 30 O2 0mA no alarm 10mA 1st threshold alarm 20mA 2nd threshold alarm by jumper selectable polarity 4 20mA output load resistor up to 200 at 12Vd...

Page 3: ...nstructions 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 v...

Page 4: ...or 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 sho...

Page 5: ...ep 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 flex...

Page 6: ...nstallation 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 dete...

Page 7: ...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 calibration kit and the TUS40 20 handheld t...

Page 8: ...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 Se...

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