What type of button will E-stops be?

• A. Lock-off (détente) self-latching mushroom operator type
• B. Momentary pushbutton
• C. Maintained latch pushbutton
• D. Self-resetting mushroom operator type

Answer: (A)

Emergency stops are designed to halt equipment and stay halted until a deliberate reset. That’s why they use a self-latching mushroom pushbutton with a lock-off action (détente). When you press it, the contacts open and the button stays depressed, keeping the machine in the stopped state. Re-energizing requires a separate reset action, so a restart can’t happen accidentally. The recognizable mushroom shape also makes it easy to hit in an emergency.

Other types don’t match this safety requirement: a momentary pushbutton wouldn’t hold the stop condition, a self-resetting type would re-enable automatically, and a simple maintained latch might not provide the necessary lock-out behavior until a manual reset.