Glossary · Protective devices and interlocks
Hold-to-run control
Also known as: hold-to-run control device
In machine safety, a hold-to-run control is a control that permits operation only while it is continuously actuated. Releasing it stops the hazardous function.
- Machine safety
- Human factors
In one sentence
A hold-to-run control keeps a machine moving only while pressed; it protects only if the operator can see the hazard zone and motion stops quickly on release.
Example
During setup of a conveyor transfer, a technician jogs the belt with a hold-to-run button, and the belt stops as soon as the button is released.
How it applies
- Machine safety: Hold-to-run controls are used in setup, maintenance or slow-motion modes, often combined with reduced speed. The person pressing the control must have a clear view of the hazard zone, and the stopping distance after release must be short.
- Limits: A hold-to-run control only protects the person operating it. Others in the area need separate protection.
- Technical documentation: Describe in which operating mode the control is available, the reduced speed and where the operator should stand.
Hold-to-run control vs. enabling device
A hold-to-run control initiates and maintains motion itself. An enabling device only permits motion that is started by another control.