How can personnel keys be used to protect operators against unexpected start-up?


A personnel key is a type of proactive inhibit function that gives an individual the control to prevent a machine being reset.


Useful in situations where there is whole body access, personnel keys contribute to protecting operators against unexpected start-up while they are inside the safeguarded space.


Fortress offers several options to reduce risk to personnel, including forced extraction and supplementary solutions.


How do personnel keys work?


The key can be released via notification of reaching the safe state or via the insertion of an access key. An operator takes the personnel key from the interlock into the safeguarded space. While that key is with the person the interlock cannot be reset.

Check out the example below to understand the steps to follow to prevent unexpected start-up with personnel key(s).

1. The forced extraction key is rotated and then be removed by the operator.

2. An additional key for a second operator can be removed if required.

3. The interlock can be opened, allowing the operator to enter the safeguarded space.

4. Until all the keys are returned, the interlock cannot be reset. This contributes to preventing unexpected start-up.

Why consider interlocks with personnel keys?


Conditions such as poor lighting, presence of obstacles or by-products from processes, can affect visibility and compromise the ability to detect personnel.


It is important to make sure that in whole body access applications the machine cannot be reset while personnel are inside the safeguarded space.


The Fortress personnel keys protect individuals with a physical in-hand object. By taking the key with them into the safeguarded space, operators have control to prevent unexpected start-up.

Check out some of our amGardpro interlocks equipped with personnel keys (with and without forced extraction)


RFID Safety Key (RSK) used as proactive inhibit function


Fortress RSK acts as a proactive inhibit function and is therefore suitable for preventing unexpected start-up.

The RFID safety key uses RFID technology to assign up to 4,000,000,000 unique codes. Keys are re-programmable and if a key is lost a new key can be taught. Engraving for key identification is also available.

Each pod can contain up to four keys. The forced extraction mechanism detects when a key is released using RFID key monitoring. Keys are locked/released via solenoids, while LEDs indicate the status of each key (unlocked/removed).



Keys can lock via solenoids

Range of actuators & escape release options available

Integration into interlock allows configuration to force extraction of personnel safety key before guard unlocks

Top view

Bottom view
Dust can drain from bottom of lock

LED status indication per key
Key unlocked and removed

LED status indication per key
Key unlocked

Safety switch state changes upon "Key Removed"
Keys can be returned to any position

Keys can be engraved for identification

If a key is lost, a new key can be taught


For more info about RSK visit the dedicated page.


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