A carbon monoxide (CO) transmitter is an electronic device with an electrochemical sensor that measures CO levels in the air and sends that data to a building automation or safety system, often via analog or digital signals. These transmitters are crucial for monitoring indoor air quality in locations like underground parking garages, boiler rooms, and industrial facilities to prevent the buildup of dangerous, invisible CO gas from sources like vehicle exhaust. 

How it Works

- Sensor: The core of the transmitter is an electrochemical sensor that reacts with CO molecules. 
- Chemical Reaction: When CO gas enters the sensor, it triggers a chemical reaction that changes the electrical current within the sensor. 
- Signal Conversion: The change in current directly correlates to the concentration of CO, and the transmitter converts this into an electrical signal. 
- Communication: This signal can be an analog output (e.g., 4-20 mA) or a digital output (e.g., Modbus RTU) that connects to a control panel or other systems to provide real-time monitoring. 

Key Features to Look For

- Electrochemical Sensor: Provides accurate, long-term measurements with excellent stability. 
- Analog Outputs: Common outputs include 0-10 VDC or 4-20 mA, which are standard for building control systems. 
- Digital Communication: Protocols like Modbus RTU allow for easy integration with digital automation systems. 
- Fast Response Time: A quick response time (e.g., less than 60 seconds) ensures immediate detection of dangerous levels. 
- Durability: A robust enclosure, such as ABS plastic, is important for harsh environments. 

Applications

- Parking Garages: To monitor vehicle exhaust from gasoline engines. 
- Mechanical Rooms & Boiler Houses: To detect CO from combustion processes. 
- Loading Docks: Similar to parking garages, for exhaust from vehicles and machinery. 
- Industrial Facilities & Tunnels: Where CO may accumulate from various industrial processes or vehicles.