How to Use Power Supply MDR-20-5: Examples, Pinouts, and Specs

The MDR-20-5 is a compact and reliable DIN-rail-mounted power supply manufactured by Meanwell. It delivers a stable 5V DC output with a maximum current of 4A, making it suitable for a wide range of industrial and automation applications. Its robust design includes built-in protections against short circuits, overloads, and overvoltage, ensuring safe and efficient operation in demanding environments.

• Industrial control systems
• Factory automation equipment
• IoT devices and embedded systems
• LED lighting systems
• Communication devices

The MDR-20-5 features screw terminal connections for input and output. Below is the pin configuration:

1. Mounting: Secure the MDR-20-5 onto a DIN rail in your control panel or enclosure.
2. Input Connection:
   • Connect the AC line (L) and neutral (N) terminals to the appropriate AC power source.
   • Ensure the input voltage is within the specified range (85-264 VAC).
3. Output Connection:
   • Connect the +V terminal to the positive rail of your circuit.
   • Connect the -V terminal to the ground rail of your circuit.
4. Load Considerations:
   • Ensure the total load does not exceed the maximum output current of 4A.
   • Use appropriately rated wires for both input and output connections.
5. Power On:
   • After verifying all connections, power on the AC source. The MDR-20-5 will provide a stable 5V DC output.

• Ventilation: Ensure adequate airflow around the power supply to prevent overheating.
• Fuse Protection: Use an external fuse or circuit breaker on the input side for added safety.
• Grounding: Properly ground the power supply to reduce electrical noise and improve safety.
• Load Regulation: For optimal performance, maintain the load within 10-90% of the rated output.

The MDR-20-5 can be used to power an Arduino UNO. Below is an example wiring and code snippet:

1. Connect the +V terminal of the MDR-20-5 to the 5V pin of the Arduino UNO.
2. Connect the -V terminal of the MDR-20-5 to the GND pin of the Arduino UNO.

// Example code to blink an LED using Arduino UNO powered by MDR-20-5

const int ledPin = 13; // Pin connected to the onboard LED

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

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

1. Can the MDR-20-5 be used with DC input?

   • Yes, it supports DC input in the range of 120-370 VDC.

2. What happens if the load exceeds 4A?

   • The power supply will activate overload protection and shut down the output to prevent damage.

3. Is the MDR-20-5 suitable for outdoor use?

   • No, it is designed for indoor use in a controlled environment.

4. Can I use the MDR-20-5 to power multiple devices?

   • Yes, as long as the total current draw does not exceed 4A.

By following this documentation, users can safely and effectively integrate the MDR-20-5 into their projects and systems.