The part number **M2UDS-E3-R2/CE** refers to a high-precision **Digital Panel Meter** manufactured by **M-System** (now MG CO., LTD). This specific model is part of the M2U series, designed to receive analog input signals and display them digitally while providing alarm outputs. ### 1. Model Breakdown The suffix and prefix characters define the specific electronic capabilities of the unit: | Code Component | Description | | :--- | :--- | | **M2UDS** | Model Series: Digital Panel Meter (with Alarm outputs) | | **E3** | **Input Type:** 4 – 20 mA DC (Current Input) | | **R2** | **Power Input:** 100 – 240V AC | | **CE** | **Certification:** Compliant with European Safety Standards (CE Marking) | --- ### 2. Key Electronic Specifications The internal electronics are designed for industrial process control, featuring high isolation and signal conditioning. * **Display:** 4-digit red LED, 10.1 mm height. * **Input Impedance:** 250 $\Omega$ (standard for 4-20mA loops). * **Alarm Outputs:** 2-point relay contacts (SPDT). * **Isolation:** 4-way isolation between input, output 1, output 2, and power. * **Sampling Rate:** 500 ms (nominal). * **Accuracy:** $\pm$0.1% of span + 1 digit. --- ### 3. Component Architecture The device consists of three primary internal electronic stages: #### A. Input Stage (Signal Conditioning) This stage uses a precision shunt resistor to convert the 4-20mA current into a voltage. It includes a **Low Pass Filter** to eliminate high-frequency noise common in industrial environments. #### B. Processing & Display An onboard **Microprocessor** handles the Analog-to-Digital conversion (ADC). It scales the raw 4-20mA signal into user-defined engineering units (e.g., 0-100% or 0-500 Liters). #### C. Output Stage (Relays) The "R2" designation indicates the presence of mechanical relays. These act as "limit switches" that trigger when the input signal crosses high or low setpoints. --- ### 4. Typical Connection Diagram (General) ```text [ Power Supply ] ------ (L) 100-240V AC (N) | [ 4-20mA Source ] ----(+) Input (-) | [ Alarm Loop 1 ] ------ Relay Contact 1 [ Alarm Loop 2 ] ------ Relay Contact 2 ```