Catalytic Bead Gas Detector 5100-02-IT

Catalytic Bead Gas Sensor Module 5100-02-IT

Sierra Monitor's 5100-02-IT module monitors combustible gases such as Methane, Hydrogen, Propane, and others.

The 5100-02-IT module is based on catalytic bead technology, a consistent and reliable method of detection that offers excellent response times to the target gases.

Combustible gas detection

As the longest rated and FM-approved calibration cycle for any catalytic bead gas sensor, the 5100-02-IT module has minimal maintenance requirements and only requires six month calibration intervals. Although the 5100-02-IT module can be used as a stand-alone sensor, it can also be used as a 4-20 mA component or as a Modbus RTU node. For higher level system capability, the module can interface directly to Sierra Monitor's Sentry IT Controller to enable system level Modbus serial communications, area and zone alarm management, extensive system diagnostic features, WebServer interface, and multiplexing sensor connections.

The Catalytic Bead Combustible Gas Sensor Module 5100-02-IT is approved and certified by a variety of third party agencies, including UL, FM, ATEX, SIL, ABS, CSA, and CE. These approvals and certifications assure our customers that we carry only the highest quality of products.


The 5100-02-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 sensors can be connected to a single controller, allowing groups of sensors 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

Optically Isolated 4-20 mA Output

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

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

6 Month Calibration Interval

Dramatically reduce maintenance 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 sensors 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

Internal Continuous Self-Diagnostics

Automatically indicate any fault or optics problems

HART Interface

Effortlessly communicate over legacy 4-20 mA analog instrumentation wiring

Model Number


Sensor Type

Catalytic Bead (Pellistor)

  • Range
  • Repeatability: +/- 1% LEL
    • Response Time: T60 < 10 sec
    • Calibration Frequency: 180 days


  • +/- 1% for 0-50% LEL range
  • +/- 2% for 51-100% LEL range

Display: Fixed and scrolling LED

Signal Output:

Sentry digital bus

Analog 4-20 mA

3-wire Non-Isolated

4-wire Isolated

Serial RS-485 Modbus RTU

Relay: Optional



  • Optional: 3 Relays (Warning, Alarm, Trouble)

HART 7 Capable

Remote Sensor: Up to 50 feet (15.2 m)


Power consumption: 3 watts max

Input voltage: 24 VDC nominal: 10-30 VDC

RFI/EMI Protection: EN50081-2, EN50082-2

Operating Range

Ambient Temperature Range: -40 oF to 176oF (-40oC to 80oC)

Relative Humidity: 0-99% Non-Condensing

  • Dimensions (H x W x D)
    • A1 & A2: 6.9 x 5.7 x 3.9 in. (17.5 x 14.5 x 9.9 cm)
    • S1 & S2: 7.5 x 5.0 x 4.4 in. (19 x 13 x 11 cm)
  • Weight
    • A1 & A2: 3.4 lb. (1.5 kg)
    • S1 & S2: 7.2 lb. (3.3 kg)
  • Housing: Epoxy coated Aluminum or 316 Stainless Steel
  • Hazardous Area Classification:
    • Explosion proof, Class 1, Div. 1, Groups B, C, D Class 1, Zone 1, Group IIC, IP66, IP 65, NEMA 4X II2 GD, Ex d IIC T6 = -40 oC to 85oC
  • Warranty: 2 years

UL 2075: ETL Approved

FM Approval 6320: Combustible Gas Detector Performance

FM Approval 3600: Class I Div. 1, Groups B, C, D

ATEX Certified: II 2G, Ex d IIB + H2 T5 Gb

IECEx Certified: Ex d IIB + H2 T5 GB

CSA Approval: For enclosure in hazardous locations

CCCF: Certificate for China

CQST: Certificate for China

SIL-2 Certified: Certified by Lloyd’s Register (IEC 61508)

CE Marked: Certificate of Approval

ABS: Certificate of Compliance

CCOE/PESO: Certificate for India

PDO Approval: Petroleum Development Oman Certificate of Registration

ISO 9001:2008: Registered Quality System

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.