Glossary · Protective devices and interlocks
Enabling device
Also known as: enabling switch
German: Zustimmeinrichtung
In machine safety, an enabling device is a manually operated device that permits machine operation only while held in a specified position. Used with a start control, it lets a person work in the hazard zone with other safeguards suspended, for example during setup or teaching.
- Machine safety
- Human factors
In one sentence
An enabling device permits machine motion only while held in position; three-position designs also stop motion when squeezed in panic.
Example
A robot programmer holds the three-position enabling switch on the teach pendant in its middle position to jog the robot at reduced speed inside the cell.
Explained in context
Context cards connect this term with others to answer one question. Also in British English and German.
How it applies
- Machine safety: An enabling device is not a start control. It only permits motion that is commanded separately, and it is normally combined with reduced speed, such as Safely-Limited Speed (SLS), in a dedicated setup operating mode.
- Human factors: Three-position devices stop motion both when released and when pressed fully, because people tend to clench their hand when startled. IEC 60204-1 describes this three-position behavior.
- Design: The enabling device must not be able to start motion when moved back to the middle position after being fully pressed.
- Technical documentation: Instructions must explain the positions, who may work with the enabling device, and that only one person should be in the hazard zone unless each person has their own device.
Enabling device vs. hold-to-run control
A hold-to-run control initiates and maintains motion. An enabling device only permits motion that another control initiates.