The **M2AC-AC4-R/CE** is a specific model within the **M2 Series** of signal conditioners (transducers) manufactured by **M-System** (now often branded under MG CO., LTD). This specific unit is a **Potentiometer Transmitter**, designed to convert a resistance change from a potentiometer into a standard DC output signal. --- ### 1. Model Code Breakdown The model name describes its internal configuration and electronic capabilities: | Code Segment | Meaning | Specification | |:--- |:--- |:--- | | **M2AC** | Base Model | Potentiometer Transmitter (Plug-in type) | | **AC4** | Input / Output | Input: Potentiometer (100 $\Omega$ to 10 k$\Omega$) / Output: 4–20 mA DC | | **R** | Power Input | 24V DC | | **CE** | Certification | CE Marking (European Safety Standards) | --- ### 2. Key Electronic Components and Architecture The internal circuitry of this device is built around three primary stages: #### A. Input Stage (Potentiometer Interface) * **Reference Voltage Source:** The device provides a stable reference voltage to the potentiometer. * **Sensing Circuit:** It measures the position of the wiper. It is designed to handle a total resistance range of **100 $\Omega$ to 10 k$\Omega$**. * **Min/Max Adjustment:** Electronic trimmers (Zero/Span) allow the user to calibrate the "0%" and "100%" points of the potentiometer. #### B. Isolation Barrier * **Three-Way Isolation:** One of the most critical electronic features. The **Input**, **Output**, and **Power Supply** are all galvanically isolated from each other. * **Benefit:** This protects downstream equipment (like a PLC) from electrical surges on the field side and eliminates ground loops. #### C. Output Stage (Current Driver) * **D/A Conversion:** Converts the processed signal into a precise analog current. * **4–20 mA Loop:** The "4" code signifies a standard industrial current loop output. * **Load Resistance:** Capable of driving a load up to **550 $\Omega$**. --- ### 3. Technical Specifications | Feature | Specification | |:--- |:--- | | **Supply Voltage** | 24V DC ($\pm$10%) | | **Power Consumption** | Approx. 3W | | **Response Time** | $\leq$ 0.5 seconds (0 – 90%) | | **Accuracy** | $\pm$0.1% of span | | **Temperature Coefficient** | $\pm$0.015% per °C | | **Isolation Resistance** | 100 M$\Omega$ at 500V DC | | **Dielectric Strength** | 2000V AC @ 1 minute | --- ### 4. Physical and Electronic Connection The unit uses a **10-pin plug-in socket** base. This allows the electronics to be replaced or serviced without disconnecting the field wiring. * **Terminals 1 & 2:** Output (+) and (-) * **Terminals 4 & 5:** Power Supply (+) and (-) * **Terminals 8, 9, 10:** Potentiometer connections (High, Wiper, Low)