The **M2RT-10-R** is a specific type of **rotary coded switch**, typically manufactured by Copal Electronics (Nidec). These components are used to manually set binary-coded values on a circuit board, often for addressing or configuration purposes. --- ### 1. Key Technical Specifications The part number "M2RT-10-R" reveals the core characteristics of the electronic component: | Feature | Specification | | :--- | :--- | | **Component Type** | Rotary Coded Switch | | **Number of Positions** | 10 (Decimal 0-9) | | **Code Type** | Real Binary Coded Decimal (BCD) | | **Actuator Type** | Shaft / Flat (Manual turn) | | **Mounting Type** | Through-hole (PCB) | | **Terminal Finish** | Gold plated (usually for high reliability) | | **Package Style** | Miniature DIP-style | --- ### 2. Functional Electronic Design The M2RT series is designed to convert mechanical rotation into a digital output. * **Logic Output:** As you rotate the shaft to a specific number (0 through 9), the internal contacts close in a specific pattern to represent that number in 4-bit binary. * **Common Terminal:** There is one "Common" (C) pin. Depending on the position, the common pin is shorted to pins 1, 2, 4, and/or 8. * **Contact Reliability:** These parts often feature a "wiping" contact mechanism which helps remove oxidation from the contacts every time the switch is turned, ensuring a low-resistance connection. --- ### 3. Pin Configuration (Internal Mapping) For a 10-position BCD switch like the M2RT-10-R, the output follows this logic table: | Position | Pin 1 | Pin 2 | Pin 4 | Pin 8 | | :--- | :---: | :---: | :---: | :---: | | **0** | Open | Open | Open | Open | | **1** | **Closed** | Open | Open | Open | | **3** | **Closed** | **Closed** | Open | Open | | **5** | **Closed** | Open | **Closed** | Open | | **9** | **Closed** | Open | Open | **Closed** | --- ### 4. Typical Applications * **Device Addressing:** Setting the ID of a device on a bus (like RS-485 or CAN bus). * **Mode Selection:** Choosing between different firmware operation modes without needing a screen or interface. * **Industrial Controls:** Used in PLCs (Programmable Logic Controllers) for manual configuration. --- ### 5. Implementation Example When connecting this to a microcontroller (like an Arduino or STM32), you would typically: 1. Connect the **Common** pin to Ground (GND). 2. Connect pins **1, 2, 4, and 8** to digital input pins. 3. Enable **Internal Pull-up Resistors** on the microcontroller pins. 4. The logic will be "Active Low" (a closed contact will read as `0` or `LOW`).