The **M2RTS-R-D4-M2/N** is a specific model within the **M2 Series** of signal conditioners produced by **M-System** (now part of MG CO., LTD). This device is a high-performance **RTD Transmitter** designed to convert signals from a Resistance Temperature Detector (RTD) into a standard DC output. --- ## 1. Technical Specifications Table | Feature | Specification Details | | :--- | :--- | | **Primary Function** | RTD Transmitter (Signal Conditioner) | | **Input Signal** | Pt 100 (Platinum RTD), 3-wire or 4-wire configurations | | **Output Signal** | 4 to 20 mA DC | | **Power Input (D4)** | 100 – 240V AC (Operating range: 85 – 264V AC) | | **Configuration (M2)** | Standard PC programmable or fixed (depending on sub-type) | | **Mounting** | DIN Rail Mounting | | **Isolation** | 3-way isolation (Input to Output to Power) | --- ## 2. Model Breakdown (Nomenclature) Understanding the alphanumeric code helps identify the specific electronic characteristics of the unit: * **M2RTS**: The series identifier for an RTD Transmitter in the M2 mini-component line. * **-R**: Indicates the output type. In this context, it typically refers to a specific current or voltage range (often 4-20mA). * **-D4**: Specifies the **Power Input**. "D4" indicates a wide-range AC power supply (100–240V AC). * **-M2**: Denotes the housing and terminal type. The M2 series is characterized by its compact, plug-in base structure. * **-N**: Usually indicates a specific option or "No specific option" depending on the regional catalog (often related to standard compliance or coating). --- ## 3. Key Electronic Components & Internal Functions The device operates through several critical electronic stages: ### A. Input Conditioning Stage This section uses a constant current source to excite the RTD sensor. It measures the resistance change and compensates for the lead-wire resistance (especially in 3-wire setups) to ensure accuracy regardless of the distance between the sensor and the transmitter. ### B. Galvanic Isolation One of the most important electronic features is the **2000V AC isolation**. It uses optoisolators or transformers to separate the input, output, and power circuits. This prevents ground loops and protects sensitive PLC/DCS equipment from high-voltage surges on the field side. ### C. Signal Conversion & Linearization RTD curves are not perfectly linear. The internal circuitry (microprocessor-based in the M2 series) performs **Linearization**, ensuring the 4-20mA output is directly proportional to the temperature, not just the raw resistance. ### D. Output Driver The final stage converts the processed signal into a stable current loop. It is designed to drive loads up to a certain resistance (typically 750Ω) even with fluctuations in the external loop power. --- ## 4. Wiring Diagram (Simplified) ```text [ FIELD SIDE ] [ TRANSMITTER ] [ CONTROL SIDE ] (RTD) (M2RTS) (PLC/DCS) Term 1 <-----------------> Input (+) Term 2 <-----------------> Input (-) ==== [ ISOLATION ] ==== Output (+) Term 3 <-----------------> Comp. ==== [ ISOLATION ] ==== Output (-) | [ Power L/N ] ``` ---