The **M2UDS2-FW5W-R2/N** is a specific model of a **Digital Bar Graph Indicator** (Signal Conditioner) manufactured by **M-System**. This device is designed to receive analog signals and provide both a visual bar graph representation and a digital display, along with alarm outputs. --- ### ## Technical Specifications The model number can be broken down into specific electronic configurations: | Feature | Specification | Description | | :--- | :--- | :--- | | **Model Series** | M2UDS2 | 1/8 DIN size Digital Bar Graph Indicator | | **Input Signal** | FW5W | 4 – 20 mA DC (Standard current input) | | **Power Input** | R2 | 100 – 240V AC | | **Option** | /N | Without specific custom options (Standard) | | **Display Type** | Dual | 101-segment LED Bar + 4-digit LED Numeric display | | **Alarm Outputs** | Relays | Typically 2 or 4 alarm points (SPDT) | --- ### ## Internal Electronic Components & Functions The device functions through several integrated electronic subsystems: 1. **Input Conditioning Stage:** * **Precision Shunt Resistor:** Converts the 4-20mA current loop into a measurable voltage. * **Isolation Circuit:** Uses optocouplers or magnetic transformers to ensure the input signal is galvanically isolated from the power supply and output, preventing ground loops. 2. **Processing Unit:** * **A/D Converter (Analog-to-Digital):** Converts the analog voltage into a digital value for the microcontroller. * **Microprocessor:** Handles the scaling of the input (e.g., converting 4mA to 0% and 20mA to 100%) and manages alarm logic. 3. **Display Drivers:** * **Bar Graph Driver:** Controls the 101-segment LED ladder. * **Numeric Display Driver:** Controls the 7-segment 4-digit numeric display for precise readings. 4. **Power Supply Unit (PSU):** * **Switch-Mode Power Supply (SMPS):** Converts the 100-240V AC input to low-voltage DC (typically 5V or 12V) required for the internal logic and sensor excitation. 5. **Output Interface:** * **Electromechanical Relays:** Provide dry contact closures for external alarms or control systems. --- ### ## Wiring Terminal Diagram (General Concept) The electronic connections are typically located on the rear of the unit: ```text [ Power Supply ] [ Input ] [ Alarm Outputs ] L --- (1) + --- (5) ALM1 --- (9) N --- (2) - --- (6) COM --- (10) G --- (3) ALM2 --- (11) ``` --- ### ## Key Electronic Features * **Galvanic Isolation:** 2000V AC isolation between input, output, and power. * **Burnout Protection:** The electronics detect if the 4-20mA loop is broken and can drive the display to a specific "Error" state. * **Scaling:** The 4-20mA input can be electronically scaled via front-panel buttons to represent engineering units (e.g., PSI, Degrees, or Liters).