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

The E Stop, or Emergency Stop switch, is a safety device designed to immediately cut power to a machine or circuit in case of an emergency. It is a fail-safe control mechanism that ensures the safety of operators and equipment by halting operations instantly when activated. E Stops are commonly used in industrial machinery, robotics, and other systems where quick power disconnection is critical to prevent accidents or damage.

• Industrial machinery and manufacturing equipment
• Robotics and automated systems
• Conveyor belts and assembly lines
• Laboratory equipment
• Emergency shutdown systems in hazardous environments

1. Wiring the E Stop:

   • Connect the COM terminal to the power source or control circuit.
   • For a Normally Closed (NC) configuration, connect the NC terminal to the load or control input. This ensures the circuit is complete during normal operation and breaks when the E Stop is pressed.
   • For a Normally Open (NO) configuration, connect the NO terminal to the load or control input. This configuration is used for triggering alarms or secondary actions when the E Stop is pressed.

2. Mounting the E Stop:

   • Drill a hole in the control panel with a diameter matching the E Stop's mounting size (e.g., 22mm or 30mm).
   • Secure the switch using the provided locking nut and ensure it is firmly in place.

3. Testing the E Stop:

   • After installation, press the E Stop to verify that it cuts power or triggers the desired action.
   • Reset the switch by twisting or pulling it, depending on the model, and ensure the circuit resumes normal operation.

• Always ensure the E Stop is easily accessible and visible to operators.
• Use appropriate wire gauges and connectors to handle the current rating of the switch.
• Regularly inspect and test the E Stop to ensure it functions correctly.
• Do not bypass or disable the E Stop, as it is a critical safety feature.
• If using the E Stop with an Arduino or microcontroller, ensure the switch is properly debounced in the code to avoid false triggers.

The following example demonstrates how to use an E Stop with an Arduino UNO to control an LED. When the E Stop is pressed, the LED turns off.

// Define pin connections
const int eStopPin = 2;  // E Stop connected to digital pin 2
const int ledPin = 13;   // LED connected to digital pin 13

void setup() {
  pinMode(eStopPin, INPUT_PULLUP); // Set E Stop pin as input with pull-up resistor
  pinMode(ledPin, OUTPUT);         // Set LED pin as output
  digitalWrite(ledPin, HIGH);      // Turn on the LED initially
}

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

  if (eStopState == LOW) {
    // If E Stop is pressed (LOW), turn off the LED
    digitalWrite(ledPin, LOW);
  } else {
    // If E Stop is not pressed, keep the LED on
    digitalWrite(ledPin, HIGH);
  }
}

Note: The E Stop is connected to the Arduino's digital pin 2 with a Normally Closed (NC) configuration. When the switch is pressed, the circuit opens, and the pin reads LOW.

1. Can I use the E Stop with both AC and DC circuits?
   Yes, the E Stop is designed to work with both AC and DC circuits within its voltage and current ratings.

2. What is the difference between NC and NO contacts?

   • NC (Normally Closed): The circuit is complete during normal operation and opens when the switch is pressed.
   • NO (Normally Open): The circuit is open during normal operation and closes when the switch is pressed.

3. How often should I test the E Stop?
   It is recommended to test the E Stop at least once a month to ensure it functions correctly.

4. Can I use the E Stop in outdoor environments?
   Yes, if the E Stop has an IP65 or higher rating, it is suitable for outdoor use. Ensure proper sealing during installation.