Enabling Switches
What are enabling switches?
Enabling switches or hold-to-run switches are used to safely operate machine functions within the machine guarding.
Only when pushed in the middle position, will the enabling switch allow that the machine functions can be operated. If the switch is released or pushed the machine will switch off immediately for safety.
Entirely modular
Pld / Ple according to EN/ISO 13849-1
Inductive handdetection
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Zeus modular enabling switches
The Zeus is a robustly designed modular enabling switch that can be composed to the user’s wishes.
The Zeus hold-to-run switch is always equipped with a robust 3-position manual switch and has the following features:
- Ergonomic design
- Robust IP67 casing
- Modular design
- Is an enabling switch as well as a gate box
- Up to 61 different machine functions can be selected
- Advanced anti-manipulation through hand detection
- Different connection options
- Can be equipped with an emergency stop, key switch and hanging detection
In-hand sensor
The Zeus Hold-to-run switch can be equipped with an in-hand sensor. An in-hand sensor provides protection against manipulation. By means of hand detection in combination with a vibration sensor, manipulation of the permission switch can be prevented.
Emergency stop
An emergency stop is required on every application, when the emergency stop is located on the machine, the accessibility must always be considered. By equipping the hold to run switch with an emergency stop, the procedure to stop the machine is much shorter and this makes for a safer situation.
61 Different machine functions
With the Zeus permission switch it is possible to directly activate, start and stop up to 61 different machine functions via the 7-segment display.
Configure your own hold-to-run switch
Emergency stop
Function buttons
3 position switch
Home sensor
Mounting bracket
Plug connection
Hand detection
LED-diagnosis
Frequently Asked Questions About Enabling Switches
An enabling switch, also called a hold-to-run switch, is a manually operated safety device used when certain machine functions need to be controlled while an operator is inside or close to a safeguarded area. The switch permits the intended machine function only while it is deliberately held in the defined enabling position.
A 3-position enabling switch has three operating states:
Position 1 – Released: Machine function is not enabled.
Position 2 – Middle position: The permitted machine function can be operated.
Position 3 – Fully pressed: The enabling function is switched off.
This three-position principle means that both releasing the device and squeezing it beyond the middle position remove the enabling signal.
The 3-position design accounts for two foreseeable operator reactions. If the operator lets go of the switch or instinctively squeezes it fully, the enabling signal is removed. Machine movement is therefore only enabled while the switch is intentionally maintained in its middle position.
Enabling switches are typically used when an operator needs controlled access for tasks such as commissioning, setup, adjustment, maintenance, troubleshooting, or repair, where certain machine functions may need to remain available under a special operating mode. Their use must form part of the machine’s risk assessment and safety concept.
Yes. Modular enabling devices can integrate additional operator controls. The ZEUS can be configured with features including an emergency stop, function buttons, key switch, hand detection, home sensor, LED diagnostics, and different connection options. Unique Safety Products states that ZEUS can be configured to select and control multiple machine functions.
An enabling device should not be fixed or manipulated so that it remains permanently in its enabling position. The ZEUS can incorporate hand detection combined with a vibration sensor to detect whether the device is actually being held, providing additional protection against manipulation.
The required safety performance depends on the complete safety function and machine risk assessment, not on the enabling switch alone. Unique Safety Products specifies enabling-switch solutions for PL d / PL e according to EN ISO 13849-1, depending on the configuration. The ZEUS also uses a robust IP67 enclosure for industrial environments.
