440T Trapped Key Solenoid Release Unit

ab guardmaster 440T solenoid release smlThe Rockwell Automation Guardmaster™ safety product - Prosafe™ solenoid release unit is used for electrical isolation of machinery to enable safe access. It consists of a RPS (rotary power switch) and a solenoid. The trapped key can be removed once a signal is given to its internal solenoid locking mechanism. An indicator light on the SRU indicates when trapped key can be removed; that is, when power is applied to the solenoid. The solenoid signal only needs to be present when key removal is necessary. The solenoid is rated for 100% duty cycle. Power to the solenoid can be removed after the trapped key is removed.
Removing the trapped key caused the isolating power switch to change state; the normally open contacts open and the normally closed contacts (if applicable) will close.

The trapped key can then be used in the next sequence of the operation.


  • Direct drive operation—positively opens contacts
  • Integral solenoid monitoring
  • Key trapped until release signal is applied
  • IP 65 enclosure or panel mounted versions
  • Replaceable code barrels
  • LED or NEON ‘key free’ indication
  • 316L stainless steel construction
  • 24V DC, 110V AC/DC or 230V AC solenoid options
  • Weatherproof stainless steel dust cap as standard
  • Conforms to ISOTR 12100, ISO 14119, IEC 947-5-1 and
  • GS-ET 19
  • Single or multiple key units available (contact factory)