How to Use E Stop: Examples, Pinouts, and Specs

• The E Stop, or Emergency Stop switch, is a safety device designed to immediately cut off power to a machine or circuit in case of an emergency. It is a critical component in industrial, commercial, and even some consumer applications where safety is a priority.
• Common applications include industrial machinery, conveyor systems, robotics, and any equipment where rapid power disconnection is necessary to prevent harm or damage.

• Type: Normally Closed (NC) or Normally Open (NO) contacts, depending on configuration
• Voltage Rating: Typically 24V to 240V AC/DC (check specific model for details)
• Current Rating: 1A to 10A (varies by model)
• Actuation Force: ~5-10N (varies by design)
• Mounting: Panel-mounted with a locking mechanism
• Reset Mechanism: Twist-to-release or pull-to-release
• Ingress Protection (IP) Rating: IP65 or higher for industrial models

The E Stop switch typically has two or more terminals for wiring. Below is a general description of the pin configuration:

Note: Some E Stop switches may have additional terminals for auxiliary contacts or indicator lights. Refer to the specific datasheet for details.

1. Wiring the E Stop:

   • Connect the COM terminal to the power source or control circuit.
   • Use the NC terminal for circuits that require disconnection when the switch is pressed.
   • Optionally, use the NO terminal for circuits that activate when the switch is pressed (e.g., triggering an alarm).

2. Mounting:

   • Drill a hole in the panel according to the switch's diameter (commonly 22mm or 30mm).
   • Secure the switch using the provided locking nut or mounting hardware.

3. Testing:

   • After installation, test the switch by pressing it to ensure it cuts off power or activates the desired circuit.
   • Reset the switch by twisting or pulling it, depending on the model.

4. Important Considerations:

   • Always ensure the switch is rated for the voltage and current of your application.
   • Use proper insulation and strain relief for wiring to prevent accidental disconnection.
   • Regularly inspect the switch for wear or damage, especially in high-use environments.

The E Stop can be used as an input to an Arduino UNO to trigger an emergency shutdown in software. Below is an example:

// Define the pin connected to the E Stop switch
const int eStopPin = 2; // Digital pin 2

void setup() {
  pinMode(eStopPin, INPUT_PULLUP); // Configure pin as input with pull-up resistor
  Serial.begin(9600); // Initialize serial communication
}

void loop() {
  // Read the state of the E Stop switch
  int eStopState = digitalRead(eStopPin);

  if (eStopState == LOW) {
    // If the switch is pressed (LOW), trigger emergency shutdown
    Serial.println("Emergency Stop Activated!");
    // Add code here to safely shut down your system
  } else {
    // If the switch is not pressed, system operates normally
    Serial.println("System Running Normally");
  }

  delay(500); // Delay for stability
}

Note: The E Stop switch is connected between the pin and ground. The internal pull-up resistor ensures the pin reads HIGH when the switch is not pressed.

1. The switch does not cut off power when pressed:

   • Ensure the wiring is correct, especially the connection to the NC terminal.
   • Verify that the switch is not damaged or worn out.

2. The switch does not reset:

   • Check if the reset mechanism (twist or pull) is functioning properly.
   • Ensure there is no debris or obstruction preventing the switch from resetting.

3. The switch activates intermittently:

   • Inspect the wiring for loose connections or frayed wires.
   • Verify that the switch is securely mounted and not subject to vibration.

• Can I use an E Stop switch in low-voltage circuits?
  Yes, as long as the switch's voltage and current ratings are compatible with your circuit.

• What is the difference between NC and NO terminals?
  NC (Normally Closed) terminals are connected when the switch is not pressed, while NO (Normally Open) terminals are connected when the switch is pressed.

• How often should I test the E Stop switch?
  It is recommended to test the switch regularly, such as during routine maintenance, to ensure it functions correctly.

• Can I use an E Stop switch outdoors?
  Yes, but ensure the switch has an appropriate IP rating (e.g., IP65 or higher) for protection against dust and water.

By following this documentation, you can safely and effectively integrate an E Stop switch into your system, ensuring reliable emergency power disconnection when needed.