The **T6613-R12** is a high-performance CO2 sensor module developed by Amphenol (formerly GE Sensing / Telaire). It is primarily designed for Indoor Air Quality (IAQ) monitoring and HVAC control systems. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Detection Method** | Non-Dispersive Infrared (NDIR) | | **Measurement Range** | 0 to 2,000 ppm (standard) | | **Accuracy** | ±30 ppm or 3% of reading (whichever is greater) | | **Operating Voltage** | 5.0 VDC ± 5% | | **Peak Current** | 190 mA | | **Average Current** | < 50 mA | | **Output Interface** | UART (Modbus) and I2C | | **Dimensions** | 57.15 mm x 34.67 mm x 15.24 mm | --- ### 2. Electronic Hardware Components The T6613-R12 is an integrated module consisting of several critical electronic sub-systems: #### A. NDIR Optical Bench This is the "heart" of the sensor. It contains: * **Infrared Source:** A micro-lamp that emits IR light. * **Optical Filter:** A narrow bandpass filter tuned to 4.26 µm (the absorption wavelength of CO2). * **IR Detector:** A thermopile or pyroelectric detector that measures the intensity of light passing through the gas chamber. #### B. Microcontroller (MCU) The module features an onboard MCU that performs the following tasks: * **Signal Processing:** Converts the analog voltage from the IR detector into a digital value. * **Calibration Logic:** Runs the **ABC Logic™** (Automatic Background Calibration) algorithm to correct for long-term drift. * **Communication:** Handles the I2C or UART protocols to talk to a master device (like an Arduino or PLC). #### C. Power Management Circuitry Since the IR source requires significant peak current (190mA) during a pulse, the board includes capacitors and voltage regulators to stabilize the power delivery and protect the logic circuits from noise. --- ### 3. Connection Pinout (Typical) The T6613-R12 uses a 12-pin interface (though not all pins are used in every application): 1. **V+**: 5V Power Supply. 2. **V-**: Ground. 3. **AV Output:** Analog voltage output (0-4V). 4. **I2C SCL:** Serial Clock for I2C communication. 5. **I2C SDA:** Serial Data for I2C communication. 6. **UART TX:** Transmit for Serial communication. 7. **UART RX:** Receive for Serial communication. --- ### 4. Key Electronic Features * **ABC Logic™:** This is a proprietary firmware feature. It tracks the lowest CO2 levels over a 14-day period and assumes these levels represent outside air (~400ppm), automatically re-calibrating the sensor to prevent sensor aging drift. * **Digital Communication:** Unlike simple analog sensors, the T6613-R12 provides robust digital data, making it less susceptible to electromagnetic interference (EMI). ---