Dwyer CMT200 vs CMS300 CO Transmitter Comparison | DLK

Dwyer CMT200 vs CMS300 CO Transmitter Comparison | DLK

Comparison Between Dwyer CMT200 and CMS300 Carbon Monoxide Transmitters

Posted on: 01/07/2026

Offering Dwyer CMT200 and CMS300 carbon monoxide transmitters with a measuring range up to 300 PPM. Features analog output for BMS connection and integrated relay for independent ventilation control, high-standard IP64 rating, ready stock at DLK.

1. Overview of Dwyer's CO Control Solutions

Carbon Monoxide (CO) is a toxic, colorless, odorless, and tasteless gas generated by the incomplete combustion of fossil fuels. In enclosed spaces such as parking garages, warehouses, maintenance facilities, or mechanical rooms, monitoring CO concentration is mandatory to protect human health and life.

As an industry leader, Dwyer Instruments (USA) provides premium air quality solutions. Among them, the CMT200 and CMS300 series are top-tier models, delivering exceptional accuracy and industrial-grade durability. However, each model is optimized for different system architectures and specific engineering needs.

2. Technical Specification Comparison Table Between CMT200 and CMS300

Specifications / Features Dwyer CMT200 Series Dwyer CMS300 Series
Core Function Carbon Monoxide Transmitter Carbon Monoxide Transmitter and Switch
Sensor Technology Electrochemical, 4-year typical lifespan, field-replaceable sensor. Electrochemical, 5-year typical lifespan, UL-recognized sensing element.
Measurement Range 0 to 200 PPM 0 to 300 PPM
Accuracy ±2% FS (Full Scale) at the time of calibration ±5 PPM or ±5% of reading for 0-300 PPM (whichever is greater)
Output Signal Jumper selectable: 4-20 mA (loop powered) or 2-10 V (load >50 kΩ) Jumper selectable: 4-20 mA (loop powered) or 2-10 V (max load 2 kΩ)
Relay Output Not available Integrated 1x SPDT relay contact. Rating: 30 VDC, 250 VAC, N/O=5A, N/C=3A resistive.
Alarm Set Points None Jumper selectable alarm set points at 25, 60, or 150 PPM
Coverage Area 5,000 to 7,000 sq. ft. typical 7,500 sq. ft. (700 m²) or 50 ft (15 m) radius
Housing Material UV resistant polycarbonate (Rugged housing optional via CMT200-R) UV resistant glass-filled polycarbonate. IP64 enclosure rating.
Weight & Dimensions 0.28 lb (0.11 kg). Compact box or round shape option. 1 lb (0.45 kg). Sturdier enclosure featuring 16 knockouts for conduit fitting.
Compliance/Certifications CE CE, ANSI/UL-2034, UL-2075, E340403

CO gas sensor CMT200 DwyerCO gas sensor CMS300 Dwyer

3. Key Differences Analysis

  • Control and Switching Capability (Relay): This is the most crucial distinction determining your system layout. The CMT200 acts purely as a transmitter—it measures CO levels and continuously transmits an analog signal to a central PLC or Building Management System (BMS). On the other hand, the CMS300 functions as a standalone control unit. Equipped with an onboard SPDT relay, the CMS300 can directly trigger ventilation fans, louvers, or local alarms when CO concentrations exceed the preset jumper limits (25, 60, or 150 PPM) without relying on a central panel.
  • Range and Sensor Longevity: The CMS300 offers a wider detection range (up to 300 PPM) compared to the CMT200 (200 PPM). Its UL-recognized electrochemical cell also has a longer typical lifespan of 5 years, slightly outperforming the 4-year lifecycle of the CMT200.
  • Environmental Protection: The housing of the CMS300 is reinforced with glass fiber and boasts an IP64 rating, making it highly robust against dust, debris, and high humidity in demanding environments.

4. Application Guide: Choosing Between CMT200 and CMS300

  • Choose the Dwyer CMT200 if: Your facility already features an established smart Building Management System (BMS) or a centralized PLC panel. The system requires continuous analog data logging over time across medium-sized zones, with ventilation automated centrally.
  • Choose the Dwyer CMS300 if: You need a localized, all-in-one monitoring and control solution. It is ideal for parking garages, loading docks, or mechanical rooms where fans must be powered up instantly upon toxic gas buildup. The CMS300 operates independently, eliminating the need and cost for an external central processing controller.
📌 Both Dwyer CMT200 and CMS300 models are currently in stock in large quantities at DLK warehouse, complete with genuine CO/CQ certification, ready to fulfill your immediate project requirements.

Contact information:
* Hotline: 093.279.2697
* Website: dlk.com.vn

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