Glossary · Protective devices and interlocks
Restart prevention
Also known as: prevention of automatic restart
German: Wiederanlaufverhinderung
In machine safety, restart prevention is a function that prevents hazardous motion from resuming automatically after power restoration, reset or removal of a protective demand, such as closing a guard.
- Machine safety
- Maintenance
In one sentence
Restart prevention stops machines from moving again on their own after a power return, reset or guard closing; a deliberate start is always required.
Example
After a power outage, a conveyor system stays stopped when power returns until an operator checks the line and presses the start button.
How it applies
- Machine safety: ISO 14118 addresses unexpected startup from all causes, and IEC 60204-1 requires that machines do not restart automatically when power is restored where this could be hazardous.
- Maintenance: Restart prevention in the control system does not replace energy isolation. For maintenance work, lockout/tagout is still needed.
- Integrated systems: In networked lines, a restart can also come from a remote command or a higher-level system after communication returns. Specify recovery behavior for these cases too.
- Technical documentation: Describe what the machine does after a power failure, a guard opening and a reset, and which action restarts it.