The **M2RT-16-R** is a rotary coded switch, typically categorized as a sub-miniature rotary DIP switch. These components are used to set configurations, addresses, or modes on a printed circuit board (PCB) without needing external software. --- ### 1. Technical Specifications The "16" in the part number indicates that this is a **Hexadecimal** switch (16 positions), while the "R" often denotes the actuator type or packaging style (Real/Right-angle or Recessed depending on the specific series). | Feature | Specification (Typical) | | :--- | :--- | | **Positions** | 16 (0 to F) | | **Output Code** | Binary Coded Hexadecimal (BCH) | | **Mounting Type** | Through-Hole (THT) | | **Actuator Style** | Arrow / Slotted (Flush or Raised) | | **Voltage Rating** | 24V DC (Switching), 50V DC (Steady) | | **Current Rating** | 100mA | | **Contact Resistance** | < 100mΩ | --- ### 2. Pin Configuration and Internal Logic The switch translates a physical rotational position into a 4-bit binary output. It usually features 5 or 6 pins: * **Common (C):** The input pin. * **Pins 1, 2, 4, 8:** The output pins representing binary weights. #### Truth Table (Example for Hexadecimal) | Position | Hex | Binary (8-4-2-1) | | :--- | :--- | :--- | | 0 | 0 | 0000 | | 5 | 5 | 0101 | | 9 | 9 | 1001 | | 10 | A | 1010 | | 15 | F | 1111 | --- ### 3. Key Components & Materials * **Housing:** High-temperature liquid crystal polymer (LCP) or PBT plastic to withstand soldering. * **Contacts:** Gold-plated over nickel. Gold is used to prevent oxidation, ensuring reliable electrical connection over many years. * **Rotor:** The internal disc that physically connects the Common pin to the specific combination of output pins. --- ### 4. Common Applications 1. **Address Setting:** Assigning a unique ID to a device on a bus (e.g., RS-485 or CAN bus). 2. **Mode Selection:** Choosing between different firmware operational modes. 3. **Industrial Controls:** Setting timers, limits, or configuration parameters on PLCs. --- ### 5. Circuit Integration Example When connecting to a microcontroller (MCU), pull-up or pull-down resistors are required to ensure stable logic levels. ```cpp // Logic for reading a 16-position switch int pin8 = digitalRead(D4); int pin4 = digitalRead(D3); int pin2 = digitalRead(D2); int pin1 = digitalRead(D1); int hexValue = (pin8 << 3) | (pin4 << 2) | (pin2 << 1) | pin1; ```