Function block
- Interface
Function description
Additional information
- Typical timing diagrams
Error detection
Error behavior
Error and status messages
- Function block specific error codes
- Function block-specific status codes (no error)

Function block

This function block is used to support function "interlocking guard with guard locking device" (safety gate monitoring) in an application.

This function block is a safety-related function block for monitoring protective equipment with a 4-stage interlocking device.

images/download/attachments/521703551/_sf_guardlocking_2_1-version-1-modificationdate-1686130803951-api-v2.png

Interface

I/O	Name	Data type	Initial value	Description
IN	Activate	BOOL	FALSE	see General parameters
IN	S_Guard	SAFEBOOL	SAFEFALSE	Variable. Monitors the interlocking protection. Can be connected to GuardOut of function block SF_Guard. SAFEFALSE: Protective equipment open. SAFETRUE: Protective equipment closed and protected area secured.
IN	S_SafetyActive	SAFEBOOL	SAFEFALSE	see General parameters
IN	S_GuardLock	SAFEBOOL	SAFEFALSE	Variable. Status of the mechanical guard locking. SAFEFALSE: Protective equipment is open. SAFETRUE: Protective equipment is closed.
IN	UnlockRequest	BOOL	FALSE	Variable. Operator intervention - Request to unlock protective equipment. SAFEFALSE: No requirement. SAFETRUE: Requirement set.
IN	S_StartReset	SAFEBOOL	SAFEFALSE	see General parameters
IN	S_AutoReset	SAFEBOOL	SAFEFALSE	see General parameters
IN	Reset	BOOL	FALSE	see General parameters Also used to request re-locking the protective equipment. The quality of the signal must be equal to a manual reset device.
OUT	Ready	BOOL	FALSE	see General parameters
OUT	S_GuardLocked	SAFEBOOL	SAFEFALSE	Interface to the hazardous area to stop. SAFEFALSE: Not a safe state. SAFETRUE: Safe state.
OUT	S_UnlockGuard	SAFEBOOL	SAFEFALSE	Signal for unlocking the protective equipment. SAFEFALSE: Close protective equipment. SAFETRUE: Unlock protective equipment.
OUT	SafetyDemand	BOOL	FALSE	Optional. see General parameters
OUT	ResetRequest	BOOL	FALSE	Optional. see General parameters
OUT	Error	BOOL	FALSE	see General parameters
OUT	DiagCode	WORD	16#0000	see General parameters

Function description

Operating process

1.	External	Requirement to set the hazardous area to a safe state - Not part of this function block
2.	Input	Feedback of the respective hazardous area: Area is in safe state (via S_SafetyActive)
3.	Input	Operator request to unlock the protective equipment (via UnlockRequest)
4.	Output	Enable signal to open the protective equipment (via S_UnlockGuard)
5.	Input	Protective equipment unlocked (via S_GuardLock). The protective equipment can now be opened. (S_GuardLocked = SAFEFALSE)
		Protective equipment opened by operator.
6.	Input	Monitoring of the protective equipment status via S_Guard - Message when the protective device is closed.
7.	Input	Operator feedback for restarting the hazardous area(reset)
8.	Output	Lock guard (S_UnlockGuard)
9.	Input	Check the locking mechanism of the protective equipment (S_GuardLock)
10.	Output	Danger zone can be operated in again (S_GuardLocked = SAFETRUE)
11.	External	Renewed operation in the danger zone

Resetting the protective equipment's guard locking device

The protective equipment's guard locking device is not permitted to be reset until it has been detected that the hazard has been eliminated from the area protected by the protective equipment. The elimination of hazard (e.g. bringing the machine or system to standstill) is determined in the safety application. The function block evaluates this safe state via input parameter S_SafetyActive.

The function block only sets output parameter S_UnlockGuard to SAFETRUE when signal SAFETRUE is present on S_SafetyActive and the function block detects a rising edge on input parameter UnlockRequest (request to reset). This output parameter controls the coil on the guard locking device mechanism used to unlatch the guard locking device on the protective equipment. In order to maintain the unlatched state, input parameter UnlockRequest must indicate a static TRUE signal after a rising edge.

Opening the protective equipment

After the guard locking device has been reset, the protective equipment can be opened. If the protective equipment is connected properly to the function block, the function block evaluates the opened state of the protective equipment using input parameter SF_Guard. If the protective equipment properly connected to the function block is open, the function block sets enable output S_GuardLocked to SAFEFALSE (safe state).

The hazard elimination detected in the safety application must continue to exist in the open state of the protective equipment (S_SafetyActive = SAFETRUE). Otherwise, the function block will change to an error state. The safe state on enable outputS_GuardLocked is maintained.

Closing the protective equipment

The protective equipment properly connected to the function block can be closed at any time.
Function block input parameter S_Guard evaluates the closed state of the protective equipment properly connected to the function block.
If UnlockRequest is still active ( TRUE ) after the protective equipment is closed, the protective equipment can then be opened again. Otherwise ( UnlockRequest = FALSE ), the function block requests the latching of the protective equipment's guard locking device ( S_UnlockGuard = SAFEFALSE ).

Latching the protective equipment's guard locking device

If the protective equipment is closed and the reset of the guard locking device is no longer being requested on input parameter UnlockRequest (i.e. request to latch), then output parameter S_UnlockGuard is set to SAFEFALSE. This output parameter must be used to control the coil on the guard locking device to latch the guard locking device. Input parameter S_GuardLock evaluates the state of the protective equipment properly connected to the function block.

If unlatched protective equipment is latched in the safety application, the function block can optionally (see Start interlock) ensure within the safe control system that enable output S_GuardLocked is not set to SAFETRUE solely by this latching. Additional manual intervention on function block input parameter Reset is required for this (see Start interlock).

S_GuardLock must indicate state SAFETRUE in the state of the function block in which the protective equipment's guard locking device is latched. If the function block detects SAFEFALSE on S_GuardLock in this state, however, then enable output S_GuardLocked is set to SAFEFALSE (safe state). This state is maintained and output as a fault by the function block.

Additional information

Typical timing diagrams

images/download/attachments/521703575/sf_guardlocking_2zeitdiagramm1_EN-version-1-modificationdate-1695291957258-api-v2.png

1) Start

2) Normal operation

3) Error

Error detection

Static signals are detected during reset. Errors are detected at the guard switches.

Error behavior

In case of an error, outputs S_GuardLocked and S_UnlockGuard are set to FALSE, output DiagCode shows the corresponding error code and output Error is set to TRUE.

An error must be acknowledged by a rising trigger at the input Reset.

Error and status messages

Function block specific error codes

DiagCode	Name	Description and output settings
C001	Reset error 0	Static reset detected in status 8x01. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C010	Guard error	S_GuardLock and S_Guard are not TRUE, although no request was made to open the door. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C011	Reset error 1	Static reset detected in status C410. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C410	Guard return	S_GuardLock and S_Guard were previously FALSE and are TRUE again (C010). Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = TRUE Error = TRUE
Cx50	Safety lost	Safety confirmation signal lost. If S_Guard = TRUE and S_GuardLock = TRUE, then x = 4 otherwise x = 0 Output signals for x = 4 (C450): Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = TRUE Error = TRUE Output signals for x = 0 (C050): Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C021	Reset error 2	Static reset detected in status C420. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C420	Safety return	Safety confirmation signal was previously FALSE and reset toTRUE (Cx50). Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = TRUE Error = TRUE
C031	Reset error 3	Static reset detected in status 8433. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C440	Unlock request error	Delay time for unlocking exceeded. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = TRUE Error = TRUE
C041	Reset error 4	Static reset detected in status C440. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE

Function block-specific status codes (no error)

DiagCode	Name	Description and output settings
0000	Idle	Function block is not active (initial state). Ready = FALSE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8000	Guard Closed and Locked	Protective equipment closed and locked. Ready = TRUE S_GuardLocked = SAFETRUE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8x01	Init	Function block has been enabled and initiated. If S_Guard = TRUE and S_GuardLock = TRUE, then x = 4 otherwise x = 8 Output signals for x = 4 (8401): Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = TRUE Error = FALSE Output signals for x = 8 (8801): Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = TRUE ResetRequest = FALSE Error = FALSE
8430	Wait for reset	The door / protective equipment is closed and locked and now waiting to be reset by the operator. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = FALSE ResetRequest = TRUE Error = FALSE
8812	Wait for operator	Waiting for operator request to open the door / protective equipment (unlocking request). Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFEFALSE SafetyDemand = TRUE ResetRequest = FALSE Error = FALSE
8822	Guard Opened and Unlocked	Interlock is released and the protective equipment is open. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = TRUE ResetRequest = FALSE Error = FALSE
8832	Guard Closed but Unlocked	Interlock is released, but the protective equipment is closed. Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = TRUE ResetRequest = FALSE Error = FALSE
8010	Wait for unlocked	S_UnlockGuard is TRUE and the confirmation signal S_GuardLock is still TRUE (waiting for confirmation <FALSE>) Ready = TRUE S_GuardLocked = SAFEFALSE S_UnlockGuard = SAFETRUE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE