The **M2RT-5B-R2/CE** is a high-precision, plug-in type signal conditioner (RTD transmitter) manufactured by **M-System**. It is designed to convert signals from a Resistance Temperature Detector (RTD) into a standard industrial DC signal. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Input Type** | RTD (Pt 100, JPt 100, etc.) | | **Output Type** | DC Current or Voltage (Configurable) | | **Power Input** | 100 – 240V AC | | **Construction** | Plug-in structure (Base socket included) | | **Isolation** | 3-way isolation (Input to Output to Power) | | **Certification** | CE Marking | --- ### 2. Main Electronic Components & Functionality The device is composed of several critical electronic stages to ensure signal integrity: #### A. Input Circuit (RTD Interface) * **Constant Current Source:** Since RTDs change resistance with temperature, the device provides a small, stable constant current to the sensor to measure the voltage drop. * **Three-wire Compensation:** It includes circuitry to compensate for lead-wire resistance, ensuring that the length of the wire between the sensor and the transmitter does not affect the temperature reading. * **Burnout Protection:** Electronic logic that detects if the sensor wire is broken. It can be configured to drive the output to a specific "Upscale" or "Downscale" limit upon failure. #### B. Signal Conditioning & Linearization * **Linearizer:** RTDs have a slightly non-linear relationship between temperature and resistance. This internal circuit "straightens" the signal so the output is perfectly proportional to the temperature. * **Zero/Span Adjustments:** Potentiometers located on the front panel allow for manual calibration of the 0% and 100% signal points. #### C. Isolation & Output Stage * **Optical/Magnetic Isolation:** Uses optocouplers or transformers to isolate the input, output, and power circuits. This prevents ground loops and protects sensitive PLC/DCS equipment from high-voltage surges. * **Output Driver:** Converts the processed signal into standard industrial formats like **4–20mA DC** or **1–5V DC**. --- ### 3. Wiring and Terminal Layout | Terminal | Function | Description | | :--- | :--- | :--- | | **1 - 2** | Output | Positive (+) and Negative (-) DC signal | | **4 - 5** | Power Supply | L and N (100-240V AC) | | **7, 8, 9** | Input | Connections for 3-wire RTD (A, B, B') | --- ### 4. Environmental & Physical Features * **Housing:** Flame-resistant black resin. * **DIN Rail Mounting:** Designed to snap onto a standard 35mm DIN rail via its base socket. * **LED Indicator:** A power LED indicates the status of the internal power supply unit.