EStops

Estops, or emergency stop devices, are safety mechanisms used to immediately halt machinery or industrial processes in emergencies. They are intended to protect workers and equipment by providing a readily accessible means to cut power or stop motion and to ensure a safe state when danger is detected.

Estops typically consist of a red, mushroom-head pushbutton or similar actuator connected to a control circuit. Many are maintained (latching) so a single press stops the machine and the device remains engaged until a reset action is performed. Some designs are lever, palm, or switch-type devices. Location, ergonomics, and distinct color and labeling are important to avoid accidental activation.

In operation, pressing the estop interrupts the machine’s safety circuit or power supply, forcing a stop command to safety PLCs or relays. After actuation, restart usually requires meeting reset conditions or cycling power, depending on the design and risk assessment.

Standards and regulation: Emergency stop devices are addressed in standards such as ISO 13850 (Safety of machinery – Emergency stop) and IEC 60204-1 (Electrical equipment of machines). These standards cover performance, reliability, proper wiring, and integration with safeguarding systems. Reliability (e.g., PFD/PL) and fail-safe behavior are considerations in modern installations.

Installation and maintenance: Estops should be positioned for quick access, protected from damage, and clearly identified as safety devices. They must be tested regularly, with procedures for functional tests and reset. In high-risk environments, redundant e-stop circuits or safe-area monitoring may be required.

See also: emergency stop, safety interlock, safety PLC.