How to Use Mean Well SDR-120-12 : Examples, Pinouts, and Specs

The Mean Well SDR-120-12 is a 120W single-output switching power supply designed for industrial applications. It provides a stable 12V DC output and is known for its high efficiency, compact size, and robust design. This power supply is ideal for use in demanding environments, offering built-in protections against overvoltage, overcurrent, and short circuits. Its DIN rail mounting capability makes it a popular choice for industrial control systems, automation equipment, and other applications requiring reliable DC power.

• Industrial automation and control systems
• Factory equipment and machinery
• LED lighting systems
• Communication systems
• Test and measurement devices

The SDR-120-12 features screw terminal connections for input and output. Below is the pin configuration:

1. Mounting: Secure the SDR-120-12 to a DIN rail (TS-35/7.5 or TS-35/15) in your control panel or enclosure.
2. Input Connection:
   • Connect the AC live wire to the L terminal.
   • Connect the AC neutral wire to the N terminal.
   • Connect the earth wire to the FG terminal for proper grounding.
3. Output Connection:
   • Connect the +V terminal to the positive side of your load.
   • Connect the -V terminal to the negative side of your load.
4. Adjusting Output Voltage (Optional):
   • Use the built-in potentiometer to fine-tune the output voltage within the range of 12V ±10%.
5. Power On:
   • Ensure all connections are secure and power on the AC input. The green LED indicator will light up, signaling normal operation.

• Input Voltage: Ensure the input voltage is within the specified range (88-264VAC or 124-370VDC).
• Load Requirements: Do not exceed the maximum output current of 10A or the total power rating of 120W.
• Ventilation: Install the power supply in a well-ventilated area to prevent overheating.
• Protection Features: The SDR-120-12 includes protections for overvoltage, overcurrent, and short circuits. If the power supply shuts down due to a fault, disconnect the load, resolve the issue, and restart the unit.

The SDR-120-12 can be used to power an Arduino UNO and other peripherals. Below is an example connection:

1. Connect the +V terminal of the SDR-120-12 to the Arduino's VIN pin.
2. Connect the -V terminal of the SDR-120-12 to the Arduino's GND pin.

// Example code to blink an LED connected to pin 13
// Ensure the Arduino is powered by the SDR-120-12 via VIN and GND

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

1. No Output Voltage:

   • Cause: Input power is not connected or is outside the specified range.
   • Solution: Verify the AC input voltage and connections to the L and N terminals.

2. Overload Protection Triggered:

   • Cause: The connected load exceeds the maximum output current (10A).
   • Solution: Reduce the load to within the rated capacity and restart the power supply.

3. Overvoltage Protection Triggered:

   • Cause: Output voltage exceeds the safe range due to a fault.
   • Solution: Disconnect the load, check for wiring issues, and restart the unit.

4. Overheating:

   • Cause: Poor ventilation or operation in a high-temperature environment.
   • Solution: Ensure adequate airflow around the power supply and operate within the specified temperature range.

• Can the SDR-120-12 be used with DC input? Yes, it supports DC input in the range of 124-370VDC.

• Is the output voltage adjustable? Yes, the output voltage can be adjusted within ±10% of 12V using the built-in potentiometer.

• What happens during a short circuit? The power supply will enter protection mode and shut down. Once the fault is cleared, it will automatically recover.

• Can I use this power supply for sensitive electronics? Yes, the SDR-120-12 provides a stable and regulated output suitable for sensitive devices like microcontrollers and sensors.

This concludes the documentation for the Mean Well SDR-120-12. For further assistance, refer to the manufacturer's datasheet or contact Mean Well support.