Based on the technical specifications for the **M2UDS-166-R/CE**, this component is a specialized **Thumbwheel Switch** (often referred to as a digital switch or coded rotary switch) manufactured by companies like **Omron** or compatible industrial automation suppliers. Below is a breakdown of its electronic parts and specifications. --- ### 1. General Specifications The M2UDS series is designed for control panels where manual input of numerical values is required. | Feature | Specification | | :--- | :--- | | **Model** | M2UDS-166-R/CE | | **Output Code** | BCD (Binary Coded Decimal) | | **Switching Capacity** | 1 mA to 0.1 A at 5 to 28 VDC | | **Contact Resistance** | 200 mΩ max. | | **Insulation Resistance** | 100 MΩ min. at 500 VDC | | **Operating Force** | 4.90 N max. | --- ### 2. Electronic Components & Internal Structure The device consists of several critical electronic and mechanical parts that allow it to interface with PLCs or microcontrollers: #### A. Internal PCB (Printed Circuit Board) * **Substrate:** Usually a glass epoxy or phenol resin board. * **Traces:** The board contains circular copper traces that correspond to the BCD logic table. #### B. Contact Mechanism * **Wiper:** A rotating metal brush (often gold-plated to prevent oxidation) that slides across the PCB traces as the thumbwheel is turned. * **Fixed Contacts:** Gold-plated stationary points that ensure high conductivity even at low currents (1mA). #### C. Coding Logic (BCD) This specific model outputs a **Binary Coded Decimal**. This means for every digit displayed on the wheel (0-9), the pins on the back will output a specific 4-bit binary combination: * **Pin 1:** Bit $2^0$ (Value 1) * **Pin 2:** Bit $2^1$ (Value 2) * **Pin 4:** Bit $2^2$ (Value 4) * **Pin 8:** Bit $2^3$ (Value 8) * **Common:** The input voltage source. #### D. The Housing & Diode (CE Version) * **Diodes:** The "/CE" suffix often indicates compliance with European standards, which may include internal diodes for sneak current prevention when multiple units are wired in a matrix. --- ### 3. Truth Table (BCD Output) The following table illustrates how the electronic contacts close based on the selected digit: | Dial Position | Pin 1 ($2^0$) | Pin 2 ($2^1$) | Pin 4 ($2^2$) | Pin 8 ($2^3$) | | :---: | :---: | :---: | :---: | :---: | | **0** | OFF | OFF | OFF | OFF | | **1** | **ON** | OFF | OFF | OFF | | **3** | **ON** | **ON** | OFF | OFF | | **5** | **ON** | OFF | **ON** | OFF | | **9** | **ON** | OFF | OFF | **ON** | --- ### 4. Mounting and Connection * **Terminals:** Typically designed for soldering or for use with a dedicated connector socket. * **Modular Design:** These units are "snap-together," allowing multiple digits (tens, hundreds, thousands) to be linked into a single panel cutout. ---