The **M2UDS-21-R/N** is a specific model of an **Electronic Timer (Delay Relay)**, typically manufactured by companies like **Autonics** (though similar numbering exists across industrial control brands). This device is used to control the timing of electrical circuits in automation and control panels. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Product Type** | Analog Timer / Time-Delay Relay | | **Mounting Type** | DIN Rail or Surface Mount (8-Pin Socket) | | **Control Method** | Analog Dial (Potentiometer) | | **Operation Mode** | ON-Delay (Power ON Start) | | **Output Contact** | SPDT (1c) or DPDT (2c) depending on sub-series | | **Power Supply** | 100–240VAC 50/60Hz / 24–240VDC (Universal) | | **Time Range** | Selectable (e.g., 0.1s to 10h) | --- ### 2. Component Breakdown #### A. Control Interface * **Rotary Dial:** Located on the front face, used to set the desired time duration. * **Time Range Selector:** A small switch (usually on the side or bottom) to change the scale from seconds to minutes or hours. * **LED Indicators:** * **PWR (Power):** Indicates the unit is energized. * **OUT (Output):** Indicates the internal relay has tripped and the contacts have changed state. #### B. The Internal Circuitry * **Microcontroller/IC:** Modern units use a dedicated timing IC for high precision and repeatability compared to old RC (Resistor-Capacitor) circuits. * **Electromagnetic Relay:** The physical switch that handles the load. When the timer reaches the set value, a coil is energized to move the contacts. * **SMPS (Switching Mode Power Supply):** Allows the device to accept a wide range of input voltages (the "Universal" voltage feature). --- ### 3. Pin Configuration (8-Pin Base) The device typically follows a standard industrial 8-pin circular layout: 1. **Pins 2 & 7:** Power Supply Input (Source). 2. **Pin 1:** Common for Contact A. 3. **Pin 3:** Normally Open (NO) for Contact A. 4. **Pin 4:** Normally Closed (NC) for Contact A. 5. **Pins 8, 6, 5:** Correspond to Common, NO, and NC for the second set of contacts (if applicable). --- ### 4. Application Example: "Motor Delay" If you want a ventilation fan to start **10 seconds after** a machine is turned on: 1. Connect the machine's power to Pins 2 and 7 of the M2UDS. 2. Set the dial to "10" and the range to "sec". 3. Wire the fan through the **Normally Open (NO)** contact. 4. When the machine starts, the timer begins counting; after 10 seconds, the relay clicks, the NO contact closes, and the fan starts. ---