The **M2TT-N5-R2/CE** is a high-precision digital temperature transmitter from the **M2 Series** (often associated with manufacturers like M-System or similar industrial automation brands). It is designed to convert signals from thermocouple or RTD sensors into a standard DC output. --- ### 1. Key Technical Specifications | Parameter | Specification Details | | :--- | :--- | | **Model Series** | M2 Series (Plug-in base) | | **Input Type** | Thermocouple (Selectable via DIP switches/Config) | | **Output Type** | DC Output (Current or Voltage) | | **Power Input** | 100 – 240V AC (Standard for 'N5' designation) | | **Configuration** | Field-configurable via PC or DIP switch | | **Isolation** | 3-way isolation (Input to output to power) | | **Approval** | CE Marking (European Conformity) | --- ### 2. Breakdown of the Model Name The alphanumeric code describes the specific hardware configuration: * **M2TT**: **M2** Series **T**hermocouple **T**ransmitter. * **N5**: Power supply requirement (typically **100 – 240V AC**). * **R2**: Output signal type (typically indicates a specific **DC voltage/current** range or dual-output capability). * **CE**: Confirms the device meets **European safety and EMC standards**. --- ### 3. Core Electronic Components & Functionality The internal circuitry is divided into three primary stages to ensure signal integrity: #### A. Input Stage (Signal Conditioning) * **Cold Junction Compensation (CJC):** Since thermocouples measure a temperature difference, an internal thermistor monitors the terminal temperature to provide an absolute reading. * **A/D Converter:** High-resolution Analog-to-Digital converter to process the millivolt ($\text{mV}$) signals from the thermocouple. * **Burnout Protection:** Circuitry that detects if the sensor wire is broken, forcing the output to a high (upscale) or low (downscale) limit. #### B. Isolation & Processing * **Microprocessor:** Linearizes the non-linear voltage curve of the thermocouple (Types K, E, J, T, B, R, S, etc.). * **Galvanic Isolation:** Uses opto-isolators or transformers to separate the input, output, and power circuits. This prevents ground loops and protects the PLC/DCS from high-voltage surges. #### C. Output Stage * **D/A Converter:** Converts the processed digital value back into a precise analog signal (e.g., $4-20\text{mA}$ or $1-5\text{V DC}$). * **Driver Circuit:** Ensures the output can drive the required load resistance (usually up to $750\Omega$ for current loops). --- ### 4. Physical Features * **Plug-in Base:** The electronic module can be removed from the base without disconnecting the field wiring. * **LED Indicators:** Front-facing LEDs usually indicate power status and error conditions (like sensor burnout). * **DIP Switches:** Located under the cover for manual range setting without needing a PC. ---