estop

An emergency stop (E-stop) is a safety device designed to immediately halt machinery or equipment in response to an emergency. It provides a clearly identifiable means for an operator to interrupt the machine’s control system and bring equipment to a safe state.

Typically, an E-stop is a red, mushroom-shaped pushbutton mounted on a yellow actuator plate. The switch contact is usually normally closed in the resting state, so pressing the button opens the circuit and stops actuators or cuts control power. Many E-stops are maintained (latching) devices that remain in the stopped state after being pressed, requiring a deliberate reset action—such as twisting, pulling, or using a key—to restore normal operation. Some installations use momentary or dual-channel configurations for added safety.

Standards and safety: E-stops are addressed by standards such as ISO 13850 (Emergency stop equipment – Functional aspects) and IEC 60947-5-5 (Electrical emergency-stop devices and controllers). Some applications reference EN 418 for guidance on emergency-stop equipment. For safety-related control systems, risk assessment per ISO 13849-1 and appropriate performance levels guide the required level of reliability and redundancy.

Implementation and maintenance: E-stops should be readily accessible, clearly marked, and protected from accidental actuation. They require regular functional testing and inspection of mechanical and electrical integrity. In safety-rated systems, E-stops are part of redundant or monitored circuits with safety relays or controllers to ensure a fail-safe stop even if part of the system fails.

Applications: E-stops are used across manufacturing, robotics, CNC machines, and process automation to provide an immediate, reliable method to stop hazardous equipment.