Electrochemical Toxic Gas Detector 5100-XX-IT

Electrochemical Toxic Gas Detector 5100-XX-IT

Sierra Monitor’s fixed 5100-XX-IT gas detector monitors toxic gases such as Hydrogen Sulfide (H2S), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Ammonia (NH3), Oxygen (O2) Deficiency, and others.

The 5100-XX-IT detector is based on electrochemical technology, a proven, less-expensive option that offers high accuracy, low power requirements, and sensitivity to a particular gas in the parts-per-million range.

toxic gas detector

The proven 5100-XX-IT fixed gas detector requires calibration only every six months, cutting operating costs and time. As part of the Sentry IT “smart” detector line, the detector can be remotely diagnosed and calibrated via Remote Sensor Capability, a valuable asset for toxic gas monitoring. The 5100-XX-IT also offers a three or four wire 4-20mA analog output signal. By integration of IT detector into a Sentry system, the user gains the capability of system Modbus serial communications, extensive diagnostics features, WebServer interface, multiplexed sensor wiring, and field-proven reliability.

The Electrochemical Toxic Gas Detector 5100-XX-IT is approved and certified by a variety of third-party agencies, including FM, CE, CSA, SIL-2, ATEX, and IECEx. These approvals and certifications assure our customers that we carry only the highest quality of products and performance.


The 5100-XX-IT supports GlobalCal™, our unique global calibration feature of the Sentry IT Controller. This allows a single technician to calibrate connected detectors from the Sentry IT Controller. With GlobalCal, the calibration happens at the controller level. Multiple detectors can be connected to a single controller, allowing groups of detectors to be calibrated at the same time. Standard gas is applied remotely, using permanently installed tubing, rather than direct delivery to the fixed gas detector.

Combined with the six-month calibration interval, GlobalCal reduces labor costs associated with calibration. The need to shut down active process areas for calibration consequently costs facilities thousands of dollars in lost production time. GlobalCal, with its remote and non-intrusive methods, allows production to continue during the calibration process, thus avoiding the costs of lost production. In addition, factory-authorized service technicians performing gas detector calibration save time and costs by remotely calibrating all gas detectors at once from the Sentry IT Controller.

Integral LED Display

Easily calibrate and access gas concentrations, relay statuses, and diagnostics

Internal Continuous Self-Diagnostics

Automatically indicate any fault or optics problems

Menu-Driven System

Rapidly adjust user-friendly configuration of alarm setpoints, calibration, maintenance, and alarm acknowledgment

MODBUS RTU Interface

Provide an easy interface to the world's most common industrial protocol interface

FM-Approved 6 Month Calibration Interval

Dramatically reduce maintenance time and half the costs as found on others for the user

SMC Sentry Digital Bus Interface

Connect easily with existing Sentry systems that have been in operation for many years

GlobalCalTM support

Non-intrusively calibrate all connected detectors at the same time without declassifying the area

Optional Remote Sensor Configuration

Access the controller over a remote network for convenience or for hard-to-access areas

Optically Isolated 4-20 mA Output

Interface effortlessly with common factory communication links and provide flexibility for the output

HART Interface

Effortlessly communicate over legacy 4-20 mA analog instrumentation wiring

Gas Type Model Std.Range(1) Opt. Max Range Resolution Response Time (2) Accuracy
Operating Range
°F °C RH*
Oxygen (O2) 5100-03-IT 5-25 % Vol 25% Vol 0.1% <10 sec. +/- 0.2%
-4 to 122 -20 to 50 15 - 99%
Carbon Monoxide (CO) 5100-04-IT 0-500PPM 1200 PPM 0.5 PPM <35 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Hydrogen Sulfide (H2S) 5100-05-IT 0-100PPM 100 PPM 0.1 PPM <35 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Chlorine (Cl2) 5100-06-IT 0-10PPM 10.0 PPM 0.1 PPM <60 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Chlorine Dioxide (ClO2) 5100-08-IT 0-3PPM 3.0 PPM 0.1 PPM <60 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Sulfur Dioxide (SO2) 5100-10-IT 0-100PPM 100 PPM 0.5 PPM <20 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Nitrogen Dioxide (NO2) 5100-12-IT 0-20PPM 20.0 PPM 0.2 PPM <35 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Hydrogen Chloride (HCL) 5100-21-IT 0-20PPM 20.0 PPM 0.1 PPM <100 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Ammonia (NH3) 5100-25-IT 0-100PPM 100 PPM 1.0 PPM <30sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Hydrogen Fluoride (HF) 5100-26-IT 0-10PPM 10 PPM 0.5 PPM <30 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
Ethylene Oxide (ETO) 5100-27-IT 0-20PPM 0-20PPM 0.1 PPM <90 sec. +/- 1PPM
-4 to 122 -20 to 50 15 - 99%
1. Optional ranges available *= Non-Condensing
2. Response time to 90% full signal value for applied concentration
Sensor Type




  • Default range as above
  • User selectable alternative ranges Sensor Life: Typically >2 years

Sensor Life: Typically >2 years


Display: Fixed and scrolling LED

Signal Outputs:

  • Sentry digital bus
  • Analog 4-20mA
    • 3-wire non-isolated
    • 4-wire isolated
  • Serial RS-485 Modbus RTU

Relay: Optional



  • 5 amp Alarm, Warning (0.25 amp Trouble)
  • 5A @ 250 VAC, 5A @ 30 VDC (Alarm, Warning)
  • Board includes auxiliary connection for Sentry multiplexing

HART: Termination board includes HART, MODBUS RS-485, 4-20mA, Digital Input, 2A Relay output, no Sentry bus


Power consumption: 2 watts maximum

Input voltage: 24 VDC nominal: 10-30 VDC

Remote Sensor Option

5100-03-IT: 10 feet

5100-04-IT: 15 feet

5100-05-IT: 15 feet

Built-in-Test (BIT)

Manual and Automatic


Dimensions: (H x W x D) (differs for 5100-25-IT & 5100-26-IT)

  • A1 & A2: 7.9 x 5.7 x 3.9 in. (20.1 x 14.5 x 9.9 cm)
  • S1 & S2: 7.6 x 4.4 x 4.9 in. (19.3 x 11.2 x 12.4 cm)


  • A1 & A2: 3.4 lb. (1.5 Kg)
  • S1 & S2: 7.2 lb. (3.3 Kg)

Housing: Epoxy-coated, die-cast, copper-free aluminum or 316 stainless steel


  • Explosion proof, Class 1, Div. 1, Groups B, C, D
  • Group IIB + H2 IP66, IP65, NEMA 4X

Warranty: 2 years


FM, CSA: For enclosure in hazardous locations

FM Performance Approval (5100-05-IT)

SIL-2 Certified (5100-04-IT, -05, -06-IT)

ATEX Certified II 2 G Ex d IIB+H2 T6 Gb

  • Ta = -20oC to 50oC (5100-05-IT)

IECEx Certified (5100-05-IT)

CE Mark (5100-05-IT)

ABS (5100-05-IT)

CQST Certified for China (5100-03, -04, -05-IT)

CCOE/PESO Certified for India

Sentry IT Fire and Gas Detection Solutions

A brief introduction to the sales, design and manufacturing facilities for Sierra Monitor Corporation's Sentry IT fire and gas solutions.

 How to Easily Calibrate Sentry IT Gas Sensors with GlobalCal

A video demonstration on how to perform GlobalCal, the simple and time-saving calibration procedure, on all Sentry IT gas sensor modules.