The **M2RT-13-R2/CE** is a high-precision, signal-conditioning transmitter manufactured by **M-System** (now MG CO., LTD). It is primarily used in industrial automation to convert RTD (Resistance Temperature Detector) signals into standardized DC output signals. --- ## 1. Technical Specifications The core electronic design of this device revolves around signal isolation and linear conversion. | Component / Feature | Specification | | :--- | :--- | | **Model Series** | M2-Unit Series | | **Input Type** | RTD (Pt 100, Pt 50, Ni 500, etc.) | | **Output Type** | 4 – 20 mA DC | | **Power Input** | 100 – 240V AC | | **Isolation** | 3-Way Isolation (Input to Output to Power) | | **Accuracy** | ±0.1% of span | | **Response Time** | ≤ 0.5 seconds (0 – 90%) | --- ## 2. Key Electronic Components & Functions ### A. The Input Circuit (RTD Interface) The device utilizes a **constant current bridge circuit**. Since RTDs change resistance based on temperature, the M2RT sends a small, stable current through the RTD to measure the voltage drop. It is designed for 3-wire compensation to cancel out lead-wire resistance errors. ### B. Isolation Barrier One of the most critical electronic features is the **Galvanic Isolation**. * **Method:** Uses optical or magnetic coupling. * **Purpose:** To prevent "ground loops" and protect sensitive control equipment (like a PLC) from high-voltage surges on the field side. ### C. Signal Conditioning & Linearization RTDs are not perfectly linear. The internal electronics include a **linearization circuit** that compensates for the non-linear characteristics of the sensor, ensuring the 4-20mA output is a direct, linear representation of the temperature. ### D. Zero & Span Adjustments On the front panel, you will find multi-turn potentiometers. * **Zero:** Adjusts the 4mA baseline. * **Span:** Adjusts the 20mA full-scale range. --- ## 3. Terminal Configuration The device uses a plug-in socket base for easy maintenance without disconnecting wires. | Terminal No. | Function | | :--- | :--- | | **1 & 2** | Power Supply (L, N) | | **4 & 5** | Output (+) and (-) | | **6, 7 & 8** | RTD Input (A, B, B') | --- ## 4. Part Number Breakdown (M2RT-13-R2/CE) * **M2RT:** Model Type (RTD Transmitter) * **1:** Input Type (e.g., Pt 100) * **3:** Output Type (4 - 20 mA) * **R2:** Power Input (100 - 240V AC) * **CE:** European Safety Compliance Mark