Sensor Products

Stand-alone Sensors
Wall-mounted RS-485 Combination Sensor with CO₂, Temperature, and Relative Humidity Capability


GreenSens GS Series
CO2 Measurement with ABC Logic

The GS-N100-W is a high performance CO2 sensor in an attractive enclosure.  It is ideal for today’s demanding DCV applications.  The GS-N100-W time-tested and reliable BACnet MS/TP and Modbus RTU firmware is superior to competitive CO2 sensors. Its reliability makes it the only approved network wall mounted CO2 sensor for GreenTrol outdoor air controllers.

Use with GreenTrol outdoor airflow controllers to provide advanced CO2-DCV or ASHRAE 62.1 compliant population-based DCV

Demonstrate compliance with ASHRAE Standards 62.1, 90.1 and 189.1

Satisfy LEED requirements

Maintain acceptable indoor air quality

Save energy


NDIR CO2 sensing technology

0 to 2,000 ppm range

ABC logic ensures long-term calibration stability

Isolated RS-485 output circuitry

Time-tested and reliable BACnet and Modbus firmware

Field selectable BACnet MS/TP or Modbus RTU protocols

BACnet master

DIP switch selectable baud rates

Attractive wall-mount package

Compatible with all GreenTrol application specific controllers

Operates on 24 VAC/DC


The GS-N100-W is a high performance CO2 sensor for today’s demanding DCV applications. It uses Telaire’s NDIR sensing technology and GreenTrol’s high performance signal processing circuitry.

The GS-N100-W time-tested and reliable BACnet MS/TP and Modbus RTU firmware is superior to competitive CO2 sensors. Its reliablilty makes it the only approved network duct mounted CO2 sensor for GreenTrol outdoor air controllers.


When combined with a GreenTrol outdoor air controller, this CO2 sensor can be used to improve traditional CO2 demand control ventilation by using a unique control algorithm that resets the outdoor air setpoint between user defined upper and lower airflow limits (not damper positions) to maintain the space CO2 level.  This control method eliminates the under- and over-ventilation that is prevalent with traditional CO2-DCV.

An even more advanced control method uses the measured airflow rate and CO2 level to estimate the population and calculates the required outdoor airflow, thus meeting the actual requirements of ASHRAE Standard 62.1.

Long term stability and high-performance components ensure years of trouble free performance.


CO2 Measurement: Provides the CO2 level in ppm via the network connection,

System Status Alarm: Yes

User Interface

Baud Rate, Protocol and Addressing: DIP switch

End of Line Termination: Jumper

Important : Modification of the factory default settings requires that power is cycled to the device. It is recommended that each device is bench configured prior to installation OR settings are provided at the time of order so that the device can be factory configured prior to shipment.

CO₂ Sensor

Technology: Telaire Non Dispersive Infrared (NDIR)

Range: 0 to 2,000 ppm

Accuracy: 400 to 1,250 ppm ±30 ppm or 3% of reading, whichever is greater
1,250 to 2,000 ppm ±5% of reading + 30 ppm

Temperature Dependence: 0.36% FS/°F [0.2% FS/°C]

Pressure Dependence: 0.33% of reading per 0.1 in. [2.54 mm] Hg

Stability: <2% of FS over life of sensor (15 year typical)

Calibration Interval: Not required when ABC logic in enabled

Response Time: <2 minutes for 90% step change typical

Signal Update: Every 4 seconds

Warmup Time: 2 minutes operational, 10 minutes to achieve maximum accuracy

Network Connection


Type: Isolated, field selectable MS/TP BACnet master or Modbus RTU connection

B.A.S. Object/Register Read/Write Access: Yes

Device Load: 1/8 load

Supported Baud Rates: 9.6, 19.2, 38.4 and 76.8 kbaud

Environmental Limits, Power Requirements & Dimensions

Environmental Limits

Temperature: 32 to 122 ⁰F [0 to 50 ⁰C]

Humidity: 5 to 95%

Power Requirement:  24 VAC (22.8 to 26.4 under load) @1.5V-A

Dimensions: 4.56H x 3.25W x 1.09D in. [115.8 x 82.6 x 27.7 mm]

Related Documents

GreenTrol Automation

156 Holly View Lane Loris, SC 29569 Toll Free 877 446 8765

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