The **M2RTS-R-D4-R2/N** is a specific model of a **Resistance Thermometer Transmitter** (RTD Transmitter) from the M2-Series, typically manufactured by **M-System**. This device is used in industrial automation to convert a temperature signal from an RTD sensor into a standard analog signal for a PLC or controller. --- ### ## Technical Specifications Breakdown The model number can be decoded based on the manufacturer’s nomenclature: | Component Code | Specification Detail | Description | | :--- | :--- | :--- | | **M2RTS** | Model Series | RTD Transmitter (Plug-in type) | | **R** | Input Type | RTD (e.g., Pt 100, JPt 100) | | **D4** | Output Signal | 4 – 20 mA DC (Current Loop) | | **R2** | Power Input | 100 – 240V AC | | **N** | Standards/Options | Typically denotes "None" or standard compliance (CE/UL depending on context) | --- ### ## Key Electronic Components & Functions The internal circuitry of this transmitter consists of several functional blocks: 1. **Input Conditioning (Bridge Circuit):** * The unit uses a constant current source to drive the RTD. * It measures the voltage drop across the RTD sensor to calculate resistance. * It includes **leadwire resistance compensation** (3-wire system) to ensure accuracy over long cable runs. 2. **Signal Isolation (Galvanic Isolation):** * This model features **three-way isolation** (Input to Output to Power). * This prevents ground loops and protects the control system from high-voltage surges on the field side. 3. **Linearizer:** * RTD resistance-temperature curves are not perfectly linear. The internal electronics include a linearizing circuit to ensure the 4-20mA output is directly proportional to the temperature, not the resistance. 4. **Zero & Span Adjustments:** * Located on the front panel, these potentiometers allow for fine-tuning the calibration of the minimum (4mA) and maximum (20mA) points. --- ### ## Wiring Terminal Configuration Typical wiring for the M2-Series base socket: | Terminal No. | Function | Connection | | :--- | :--- | :--- | | **1** | Output (+) | 4-20mA Signal to PLC | | **2** | Output (-) | Signal Ground | | **3** | Input (A) | RTD Lead A | | **4** | Input (B) | RTD Lead B | | **5** | Input (b) | RTD Lead b (Compensation) | | **7** | Power (U) | 100-240V AC (Live) | | **8** | Power (V) | 100-240V AC (Neutral) | --- ### ## Diagnostic Indicators * **Power LED:** Indicates the internal DC power supply is healthy. * **Burnout Protection:** The electronics are designed to drive the output to a specific state (Upscale >20mA or Downscale <4mA) if the RTD wire breaks, alerting the control system to a sensor failure.