The **M2RTS-S-AE-R2** is a specific model of an **RTD Transmitter** (Resistance Temperature Detector) produced by **M-System**. It is designed to convert temperature signals from an RTD sensor into a standard analog process signal (like 4-20mA or 0-10V). Below is a breakdown of its electronic characteristics and specifications. --- ### 1. Technical Specifications This device is a plug-in type signal conditioner. The model code breaks down as follows: | Feature | Specification | | :--- | :--- | | **Input Type** | Pt 100 (ITS-90) RTD | | **Output Type** | Selectable (e.g., 4–20 mA DC, 0–10V DC) | | **Power Input** | 100 – 240V AC (Standard "AE" code) | | **Construction** | Plug-in base socket mount | | **Isolation** | 3-way (Input to Output to Power) | | **Accuracy** | ±0.1% of span | --- ### 2. Key Electronic Components & Functions The internal circuitry of the M2RTS-S-AE-R2 consists of several critical stages: #### A. Input Conditioning Stage * **Constant Current Source:** To measure the resistance of an RTD (like Pt100), the device sends a small, stable constant current through the sensor. * **Lead-wire Compensation:** Since the resistance of the wires connecting the sensor can affect the reading, the electronic circuit uses a 3-wire system to calculate and cancel out lead-wire resistance. * **Burnout Protection:** Includes a circuit that detects if the sensor wire is broken. It can be configured to drive the output "Upscale" or "Downscale" upon failure. #### B. Signal Processing (Linearization) * **Non-linear to Linear Conversion:** RTD resistance does not change perfectly linearly with temperature. The electronic logic inside the transmitter linearizes the signal so that the output (e.g., 4mA at 0°C and 20mA at 100°C) is proportional to the temperature. #### C. Isolation and Output Stage * **Optical/Magnetic Isolation:** To prevent ground loops and protect sensitive PLC/DCS equipment, the device uses galvanic isolation between the field input, the power supply, and the output signal. * **Operational Amplifiers (Op-Amps):** High-precision amplifiers scale the processed signal to the desired industrial output level. --- ### 3. Connection Diagram (General) The electronics are accessed via a 10-pin or 11-pin socket. ```text Terminal | Function ---------|--------------------------- 1 & 2 | Output Signal (+ / -) 4 & 5 | Power Supply (L / N) 6 | Ground (GND) 7, 8, 9 | RTD Input (A, B, B') ``` --- ### 4. Environmental & Physical Features * **Status Indicator:** Usually features a front-facing LED to indicate power status. * **Adjustments:** Contains "Zero" and "Span" potentiometers (trimmers) on the front panel for fine-tuning the calibration in the field. * **Housing:** High-impact plastic casing designed for DIN rail or surface mounting via a base socket.