Infrared CO2 Gas Sensor Module 5100-88-IT

Sierra Monitor’s 5100-88-IT module monitors Carbon Dioxide (CO2), a toxic gas that is particularly dangerous in enclosed areas. This sensor monitors for adequate indoor air quality (IAQ) to ensure a healthy, comfortable, and productive work environment.

The 5100-88-IT module is based on infrared (IR) technology, an accurate and stable method of detection that requires low maintenance and can operate in low oxygen environments and not be poisoned by toxic gases.

As the release of Carbon Dioxide rises, it is important to install 5100-88-IT modules in facility ceilings and roofs. However, the result of installing the modules in high places requires more time and maintenance to calibrate them. With features such as non-intrusive calibration and remote sensor configuration, facility managers can calibrate and configure the module in hard to access areas without much effort. In addition, the 5100-88-IT only requires calibration at 1 year intervals, drastically reducing operating costs. Although the 5100-28-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 Controller to enable system level Modbus serial communications, area and zone alarm management, extensive system diagnostic features, WebServer interface, and multiplexing sensor connections.


The 5100-88-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 one-year 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.

Infrared CO2 Gas Sensor Module 5100-88-IT

  • GlobalCal™ support – Non-intrusively calibrate all connected sensors at the same time without declassifying the area
  • Menu-driven system: Rapidly adjust user-friendly configuration of alarm setpoints, calibration, maintenance, and alarm acknowledgment
  • Integral LED Display: Easily calibrate and access gas concentrations, relay statuses, and diagnostics
  • 1 Year Calibration Interval: Dramatically reduce maintenance and operating costs for the user
  • Internal Continuous Self-Diagnostics: Automatically indicate any fault or optics problems
  • Network compatible with Modbus, 4-20mA, HART, relay interface: Easily install in a variety of field applications and easily obtain critical safety information wherever needed
  • Modbus RTU Serial Interface: Provide an easy interface to the world’s most common industrial protocol
  • SMC Sentry Digital Bus Interface: Connect easily with existing Sentry systems that have been in operation for many years
  • Stainless Steel 316 or Epoxy-Coated Aluminum enclosures: Meet specific installation needs with different enclosure materials
  • Remote Sensor Configuration: Remotely configure module for hard to access areas up to 100 feet away

Specifications for Infrared CO2 Gas Sensor Module 5100-88-IT

Sensor Type

  • Infrared, Dual Wavelength


  • Range: 0-5000 ppm Carbon Dioxide
  • Repeatability: +/- 1%
  • Accuracy +/- 2%
  • Sensor Life: Typically >5 years
  • Heated Sensor: Heated cell to prevent condensation
  • Response Time: T60 <20 seconds


  • Display: Fixed and scrolling LED
  • Signal Outputs:
    • Sentry digital bus
    • Analog 4-20 mA
      • 3-wire Non-Isolated
      • 4-wire Isolated
    • Serial RS-485 Modbus RTU
  • Relay: Optional


  • Relays
    • 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, 4-20 mA, Digital Input, 2A relay output, no Sentry bus


  • Power Consumption: 3 watts
  • Input voltage: 24 VDC nominal: 10-30 VDC

Operating Range

  • Ambient Temperature Range: -4 o to 140oF (-20o to 60oC)
  • Relative Humidity: 0-99% Non-Condensing


  • Dimensions (H x W x D)
    • A1: 7.8 x 5.7 x 3.9 in. (19.8 x 14.5 x 9.9 cm)
    • A2: 8.1 x 4.8 x 4.9 in. (21 x 12 x 12 cm)
    • S1 & S2: 7.5 x 4.4 x 4.9 in. (19 x 11 x 12 cm)
  • Weight
    • A1: 3.4 lb. (1.5 Kg)
    • A2: 5.4 lb. (2.5 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 I, Zone 1
    • Group IIC, IP66, IP65, NEMA 4X, T6
    • TA = -40oC to 85oC II2 GD, Ex d IIC
  • Warranty: 2 years