Mitsubishi Electric MELSEC iQ-R Series Safety Function Block Reference page 46

FB details
This FB controls the guard lock and monitors the position of the guard and the lock. This FB can be used with a mechanical
locked switch. The operator requests to get access to the hazardous area. The guard can only be unlocked when the
hazardous area is in a safe state. The guard can be locked if the guard is closed. The machine can be started when the guard
is closed and the guard is locked. An open guard or unlocked guard will be detected in the event of a safety-critical situation.
Ex.
Operation sequence for guardlock
No. I/O

Sequence 1
Sequence 2 In
Sequence 3 In
Sequence 4 Out
Sequence 5 In
Sequence  
Sequence 6 In
Sequence 7 In
Sequence 8 Out
Sequence 9 In
Sequence 10 Out
Sequence 11 
Sequence 1, 2
i_bS_SafetyActive
=ON
M+SF_GLOCK+R
Sequence 6
i_bS_GuardMon
=ON
M+SF_GLOCK+R
4 SAFETY FB SPECIFICATIONS
44
4.7 M+SF_GLOCK_R
Operation
Request to get the hazardous area to a safe state - not part of this FB
Feedback from applicable hazardous area that it is in a safe state (via i_bS_SafetyActive)
Operator request to unlock the guard (i_bUnlockRequest input=ON)
Output the signal unlocking the guard to the switch (by setting o_bS_UnlockGuard to ON).
The signal that enables the guard to be unlocked is input from the switch (by setting i_bS_GuardLock input to
OFF), which enables the guard to be opened. (o_bS_GuardLocked is set to OFF)
Operator opens the guard.
Check if the guard is closed again. (by setting i_bS_GuardMon to ON)
Feedback from operator to restart the hazardous area (i_bUnlockRequest)
Lock the guard. (o_bS_UnlockGuard)
Check if guard is locked. (i_bS_GuardLock)
Hazardous area can operate again. (o_bS_GuardLocked=ON) (If i_bS_AutoReset is OFF, reset is required with
i_bReset input.)
Restart the operation in the hazardous area.
Sequence 3, 4
o_bS_UnlockGuard
=ON
M+SF_GLOCK+R
i_bUnlockRequest
=ON
Sequence 7, 8
o_bS_UnlockGuard
=OFF
M+SF_GLOCK+R
i_bUnlockRequest
=OFF
Sequence 5
i_bS_GuardLock
=OFF
o_bS_GuardLocked
=OFF
M+SF_GLOCK+R
Sequence 9
i_bS_GuardLock
=ON
M+SF_GLOCK+R
Sequence -
i_bS_GuardMon
=OFF
M+SF_GLOCK+R
Sequence 10, 11
o_bS_GuardLocked
=ON
M+SF_GLOCK+R
i_bReset