The **M2UDS-K4W-R2/N** is a specific model within the **M2UDS Series** of digital multi-meters or panel indicators manufactured by **M-System** (now part of MG CO., LTD). These devices are typically used in industrial automation for monitoring and displaying analog signals. ### 1. Technical Specifications Below are the primary electronic characteristics of the M2UDS-K4W-R2/N: | Feature | Specification | |:---|:---| | **Series** | M2UDS (Digital Panel Meter) | | **Input Signal** | 4 – 20 mA DC (denoted by "K") | | **Power Input** | 100 – 240V AC (denoted by "W") | | **Relay Output** | 2 points, SPDT (denoted by "R2") | | **Optional Suffix** | /N (Specific coating or standard variant) | | **Display** | 4-digit Red LED | | **Mounting** | Plug-in base (11-pin) | --- ### 2. Breakdown of the Model Code To understand the electronic components and their functions, the model code can be dissected as follows: - **M2UDS**: The base series for a digital indicator with alarm outputs. - **K**: **Input type.** In this configuration, "K" represents a DC current input, specifically 4 to 20 mA. - **4**: **Display characters.** This indicates a 4-digit display range (usually -1999 to 9999). - **W**: **Power supply.** "W" stands for universal AC power, supporting 100V to 240V AC. - **R2**: **Alarm output.** This unit features two relay contact outputs (Hi/Lo or Hi/Hi, etc.) for process control or safety shutdowns. - **N**: **Special options.** Often refers to specific terminal treatments or standard non-certified variations depending on the regional datasheet. --- ### 3. Electronic Architecture The device operates through three main internal stages: 1. **Input Conditioning:** The 4-20mA current signal is passed through a precision shunt resistor to convert it into a voltage, which is then filtered to remove industrial noise. 2. **A/D Conversion & Processing:** A microprocessor samples the analog voltage using an Analog-to-Digital converter. The CPU scales this value based on user-defined parameters to show physical units (e.g., PSI, temperature, or flow). 3. **Output Logic:** * **Visual:** Drives the LED segment display. * **Relays:** If the measured value exceeds or falls below setpoints, the CPU triggers electromagnetic relays to open or close external circuits. ### 4. Wiring Diagram (Simplified) The device typically uses a standard 11-pin circular socket base. ```text Pin Connection Guide: 1 & 11: Power Supply (100-240V AC) 5 (+) & 6 (-): Input Signal (4-20mA) 1, 3, 4: Relay 1 (Common, NC, NO) 8, 9, 10: Relay 2 (Common, NC, NO) ``` --- ### 5. Key Applications * **Tank Level Monitoring:** Converting a level sensor's 4-20mA signal into a percentage or liter display. * **Pressure Control:** Using the `R2` relay outputs to trigger an alarm if a pipe reaches critical pressure. * **Process Visualization:** Providing a local readout in a control cabinet for operators.