How to Use Emergency STOP: Examples, Pinouts, and Specs

An Emergency Stop (E-STOP) button is a critical safety device designed to halt the operation of machinery and processes in the event of an emergency. It is a fail-safe control mechanism that can be activated with a simple push, providing an immediate response to potential hazards. E-STOP buttons are commonly found in industrial settings, on control panels, and within electronic systems where human safety or equipment protection is paramount.

• Industrial machinery
• Robotic systems
• Conveyor belts
• Automated production lines
• CNC machines
• Laboratory equipment

• Voltage Rating: Typically 24V to 240V AC/DC
• Current Rating: Up to 10A (varies by model)
• Contact Configuration: Normally closed (NC), opens upon activation
• Durability: Rated for a high number of cycles (mechanical and electrical)

1. Wiring the E-STOP Button:

   • Connect the COM pin to the positive terminal of the power supply.
   • Connect the NC pin to the control circuit that needs to be interrupted during an emergency.

2. Mounting the E-STOP Button:

   • Place the E-STOP button in an accessible location.
   • Ensure it is clearly marked and unobstructed.

3. Testing the E-STOP Button:

   • Perform regular tests to ensure functionality.
   • Check for mechanical freedom and reliable contact break.

• Visibility: The E-STOP button should be highly visible and marked with a red color.
• Accessibility: It must be easily accessible and within reach of the operator at all times.
• Wiring: Use appropriate gauge wire to handle the expected current.
• Compliance: Ensure the E-STOP button meets relevant safety standards and regulations.

• E-STOP Button Does Not Respond:

  • Check the wiring connections for any loose or broken wires.
  • Verify the power supply is functioning and delivering the correct voltage.
  • Inspect the button for any physical damage or obstructions.

• False Triggering:

  • Ensure there is no vibration or mechanical stress causing accidental activation.
  • Check for any electrical interference that may cause unintended operation.

• Regularly inspect and maintain the E-STOP button for reliable performance.
• If the button is unresponsive, consider replacing it as it is a critical safety component.
• For false triggering, isolate the button from sources of interference or mechanical stress.

Q: Can I use the NO pin for an E-STOP function? A: No, the E-STOP function should always use the NC contact to ensure the circuit is broken in an emergency.

Q: How often should I test the E-STOP button? A: It is recommended to test the E-STOP button before each use of the machinery or at least once a month.

Q: What should I do if the E-STOP button is accidentally activated? A: Reset the system according to the manufacturer's instructions, ensuring that it is safe to resume operation.

// Define the E-STOP button pin
const int estopPin = 2;

void setup() {
  // Set the E-STOP pin as an input with an internal pull-up resistor
  pinMode(estopPin, INPUT_PULLUP);
  // Initialize serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Check the E-STOP button state
  int estopState = digitalRead(estopPin);
  
  // If the button is pressed (circuit is open), halt the system
  if (estopState == HIGH) {
    // Implement emergency stop procedures
    Serial.println("EMERGENCY STOP ACTIVATED");
    // Add code here to safely shut down any connected systems
    // ...
  }
  // Otherwise, continue normal operation
  else {
    // Normal operation code
    // ...
  }
}

Note: In this example, the Arduino's internal pull-up resistor is used, which means the E-STOP button is connected between the pin and ground. The circuit is normally closed, and when the E-STOP is pressed, the circuit opens, reading HIGH on the input pin.