SF_MutingSeq

This is the web edition of the original ‎⮫ AC500-S safety user manual, version 1.3.2. This web edition is provided for quick reference only. The original safety user manual must be used to meet functional safety application requirements.

Standards	Requirements
IEC 61496-1:2012	A.7 Muting A.7.1.2 There shall be at least two independent hard-wired muting signal sources to initiate the function. It shall not be possible to initiate muting when the OSSDs are already in the OFF-state. A.7.1.3 The mute function shall only be initiated by the correct sequence and/or timing of the mute signals. Should conflicting muting signals occur, the ESPE shall not allow a muted condition to occur. A.7.1.4 There shall be at least two independent hard-wired muting signal sources to stop the function. The muting function shall stop when the first of these muting signals changes state. The deactivation of the muting function shall not rely only on the clearance of the ESPE. A.7.1.5 The muting signals should be continuously present during muting. When the signals are not continuously present, an incorrect sequence and/or the expiration of a pre-set time limit shall cause either a lock-out condition or a restart interlock. A.7.4 Indication: A mute status signal or indicator shall be provided (in some applications, an indication signal of muting is necessary)
IEC / TS 62046 Ed. 2:2008	5.5. General application requirements for muting
ISO 13849-1:2015	5.2.2 Manual reset function
ISO 12100-2:2010	6.2.11.4: Restart following power failure/spontaneous restart

Muting is the intended suppression of the safety function (e.g., light barriers). In this FB, sequential muting with four muting sensors is specified.

This is required, e.g., when transporting the material into the danger zone without causing the machine to stop. Muting is triggered by muting sensors. The use of two or four muting sensors and correct integration into the production sequence must ensure that no persons enter the danger zone while the light curtain is muted. Muting sensors can be proximity switches, photoelectric barriers, limit switches, etc. which do not have to be fail-safe. Active muting mode must be indicated by indicator lights.

There are sequential and parallel muting procedures. In this FB, sequential muting with four muting sensors was used; an explanation for the forward direction of transportation is provided below. The FB can be used in both directions, forward and backward. The muting should be enabled with the MutingEnable signal by the process control to avoid manipulation. When the MutingEnable signal is not available, this input must be set to TRUE.

The FB input parameters include the signals of the four muting sensors (MutingSwitch11 ... MutingSwitch22) as well as the OSSD signal from the AOPD device (S_AOPD_In).

The S_StartReset input shall only be activated if it is ensured that no hazardous situation can occur when the PES is started.

Table 1056: FB name: SF_MutingSeq
Name	Data type	Initial value	Description, parameter values
VAR_INPUT
Activate	BOOL	FALSE	⮫ Table 1021 “General input parameters”
S_AOPD_In	BOOL	FALSE	Variable. OSSD signal from AOPD. FALSE: Protection field interrupted. TRUE: Protection field not interrupted.
MutingSwitch11	BOOL	FALSE	Variable. Status of muting sensor 11. FALSE: Muting sensor 11 not actuated. TRUE: Workpiece actuates muting sensor 11.
MutingSwitch12	BOOL	FALSE	Variable. Status of muting sensor 12. FALSE: Muting sensor 12 not actuated. TRUE: Workpiece actuates muting sensor 12.
MutingSwitch21	BOOL	FALSE	Variable. Status of muting sensor 21. FALSE: Muting sensor 21 not actuated. TRUE: Workpiece actuates muting sensor 21.
MutingSwitch22	BOOL	FALSE	Variable. Status of muting sensor 22. FALSE: Muting sensor 22 not actuated. TRUE: Workpiece actuates muting sensor 22.
MutingEnable	BOOL	FALSE	Variable or constant. Command by the control system that enables the start of the muting function when needed by the machine cycle. After the start of the muting function, this signal can be switched off. FALSE: Muting not enabled. TRUE: Start of muting function enabled.
S_StartReset	BOOL	FALSE	⮫ Table 1021 “General input parameters”
Reset	BOOL	FALSE	⮫ Table 1021 “General input parameters”
MaxMutingTime	TIME	T#0s	Constant 0 .. 120 min (application specific). Maximum time for complete muting sequence, timer started when second muting sensor is actuated. If needed this can be combined with SF_Override.
VAR_OUTPUT
Ready	BOOL	FALSE	⮫ Table 1022 “General output parameters”
S_AOPD_Out	BOOL	FALSE	Safety related output, indicates status of the muted guard. FALSE: AOPD protection field interrupted and muting not active. TRUE: AOPD protection field not interrupted or muting active.
S_MutingActive	BOOL	FALSE	Indicates status of muting process. FALSE: Muting not active. TRUE: Muting active.
SafetyDemand	BOOL	FALSE	Optional. ⮫ Table 1022 “General output parameters”
ResetRequest	BOOL	FALSE	Optional. ⮫ Table 1022 “General output parameters”
Error	BOOL	FALSE	⮫ Table 1022 “General output parameters”
DiagCode	WORD	16#0000	⮫ Table 1022 “General output parameters”

Note: A short circuit in the muting sensor signals or a functional application error to supply these signals is not detected by this FB but interpreted as incorrect muting sequence. However, this condition should not lead to unwanted muting. The user should take care to include this in the risk analysis.

Example for SF_MutingSeq in forward direction with four sensors

1

If muting sensor MutingSwitch12 (MS_12) is activated by the product after MutingSwitch11 (MS_11), the muting mode is activated and the MaxMutingTime timer is started.

2

Muting mode remains active as long as MutingSwitch11 (MS_11) and MutingSwitch12 (MS_12) are activated by the product. The product may pass through the light curtain without causing a machine stop.

3

Before muting sensors MutingSwitch11 (MS_11) and MutingSwitch12 (MS_12) are disabled, muting sensors MutingSwitch21 (MS_21) and MutingSwitch22 (MS_22) must be activated. This ensures that muting mode remains active.

4

Muting mode is terminated if only muting sensor MutingSwitch22 (MS_22) is activated by the product.

Muting conditions

Forward direction

Muting condition 1 (to 8010) (MS_11 is the first entry switch actuated):

MutingEnable AND (R_TRIG at MS_11 AND NOT MS_12 AND NOT MS_21 AND NOT MS_22)

Muting condition 2 (from 8010 to 8020) (MS_12 is the second entry switch actuated). Start timer MaxMutingTime:

MutingEnable AND (MS_11 AND R_TRIG at MS_12 AND NOT MS_21 AND NOT MS_22)

Muting condition 3 (from 8020 to 8000) (MS_21 is the first exit switch released). Stop timer MaxMutingTime:

NOT MS_11 AND NOT MS_12 AND F_TRIG at MS_21 AND MS_22

Backward direction

Muting condition 11 (to 8120) (MS_22 is the first entry switch actuated):

MutingEnable AND (NOT MS_11 AND NOT MS_12 AND NOT MS_21 AND R_TRIG at MS_22)

Muting condition 12 (from 8120 to 8110) (MS_21 is the second entry switch actuated). Start timer MaxMutingTime:

MutingEnable AND (NOT MS_11 AND NOT MS_12 AND R_TRIG at MS_21 AND MS_22)

Muting condition 13 (MS_12 is the first exit switch released). Stop timer MaxMutingTime:

MS_11 AND F_TRIG at MS_12 AND NOT MS_21 AND NOT MS_22

Specification of wrong muting sequences:

In state 8000

(NOT MutingEnable AND R_TRIG at MS_11)

OR (NOT MutingEnable AND R_TRIG at MS_22)

OR (MS_12 OR MS_21)

OR (MS_11 AND MS_22)

In state 8010

NOT MutingEnable OR NOT MS_11 OR MS_21 OR MS_22

In state 8020

R_TRIG at MS_11 OR R_TRIG at MS_12 OR F_TRIG at MS_22

OR (MS_11 AND F_TRIG at MS_12)

OR ((MS_11 OR MS_12) AND (F_TRIG at MS_21))

OR ((NOT MS_11 OR NOT MS_12) AND NOT MS_22)

OR ((NOT MS_11 OR NOT MS_12 OR NOT MS_21) AND R_TRIG at MS_22)

OR ((MS_11 AND MS_22) AND (NOT MS_12 OR NOT MS_21))

OR (R_TRIG at MS_21 AND R_TRIG at MS_22)

OR (F_TRIG at MS_11 AND F_TRIG at MS_12)

OR (F_TRIG at MS_12 AND F_TRIG at MS_21)

OR (NOT MS_11 AND MS_12 AND NOT MS_21)

In state 8120

NOT MutingEnable OR MS_11 OR MS_12 OR NOT MS_22

In state 8110

F_TRIG at MS_11 OR R_TRIG at MS_21 OR R_TRIG at MS_22

OR (MS_22 AND F_TRIG at MS_21)

OR ((MS_22 OR MS_21) AND (F_TRIG at MS_12))

OR ((NOT MS_22 OR NOT MS_21) AND NOT MS_11)

OR ((NOT MS_22 OR NOT MS_21 OR NOT MS_12) AND R_TRIG at MS_11)

OR ((MS_11 AND MS_22) AND (NOT MS_12 OR NOT MS_21))

OR (R_TRIG at MS_11 AND R_TRIG at MS_12)

OR (F_TRIG at MS_22 AND F_TRIG at MS_21)

OR (F_TRIG at MS_21 AND F_TRIG at MS_12)

OR (NOT MS_12 AND MS_21 AND NOT MS_22)

Typical timing diagrams

SF_MutingSeq_TimingDiagram_1 — Fig. 538: Typical timing diagram for SF_MutingSeq: S_StartReset = FALSE

SF_MutingSeq_TimingDiagram_2 — Fig. 539: Typical timing diagram for SF_MutingSeq: S_StartReset = TRUE

Error detection

The FB detects the following error conditions:

Muting sensors MutingSwitch11, MutingSwitch12, MutingSwitch21, and MutingSwitch22 are activated in the wrong order.
Muting sequence starts without being enabled by MutingEnable.
A static Reset condition.
MaxMutingTime has been set to a value less than T#0s or greater than T#120min.
The muting function (S_MutingActive = TRUE) exceeds the maximum muting time MaxMutingTime.

Error behavior

In the event of an error, the S_AOPD_Out and S_MutingActive outputs are set to FALSE. The DiagCode output indicates the relevant error code and the Error output is set to TRUE.

A restart is inhibited until the error conditions are cleared and the safe state is acknowledged with Reset by the operator.

Function block-specific error and status codes

Table 1057: FB-specific error codes
DiagCode	State name	State description and output setting
C001	Reset Error 1	Static Reset condition detected after FB activation. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C011	Reset Error 2	Static Reset condition detected in state 8402. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
CYx4	Error Muting sequence	Error detected in muting sequence in states 8000, 8010, 8020, 8120 or 8110. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE Y = Status in the sequence (2 states for forward and 2 states for backward direction). C0x4 = Error occurred in state 8000 C1x4 = Error occurred in state Forward 8010 C2x4 = Error occurred in state Forward 8020 C3x4 = Error occurred in state Backward 8120 C4x4 = Error occurred in state Backward 8110 CFx4 = Muting enable missing x = Status of the sensors when error occurred (4 bits: LSB = MS_11; MS_12; MS_21; MSB = MS_22).
C010	Parameter Error	MaxMutingTime value out of range. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE
C020	Error Timer MaxMuting	Timing error: Active muting time (when S_MutingActive = TRUE) exceeds MaxMutingTime. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = TRUE

Table 1058: FB-specific status codes (no error):
DiagCode	State name	State description and output setting
0000	Idle	The function block is not active (initial state). Ready = FALSE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8000	AOPD Free	Muting not active and no safety demand from AOPD. Ready = TRUE S_AOPD_Out = TRUE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8401	Init	Function block has been activated. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = TRUE Error = FALSE
8802	Safety Demand AOPD	Safety demand detected by AOPD, muting not active. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = TRUE ResetRequest = FALSE Error = FALSE
8402	Wait for Reset	Safety demand or errors have been detected and are now cleared. Operator acknowledgment by Reset required. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = TRUE Error = FALSE
8002	Safe	Safety function activated. Ready = TRUE S_AOPD_Out = FALSE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8010	Muting Forward Start	Muting forward, sequence is in starting phase and no safety demand. Ready = TRUE S_AOPD_Out = TRUE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8020	Muting Forward Active	Muting forward, sequence is active. Ready = TRUE S_AOPD_Out = TRUE S_MutingActive = TRUE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8110	Muting Backward Active	Muting backward, sequence is active. Ready = TRUE S_AOPD_Out = TRUE S_MutingActive = TRUE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE
8120	Muting Backward Start	Muting backward, sequence is in starting phase and no safety demand. Ready = TRUE S_AOPD_Out = TRUE S_MutingActive = FALSE SafetyDemand = FALSE ResetRequest = FALSE Error = FALSE