SF_Antivalent

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
ISO 13849-1:2015	6.2.6 Category 3 6.2.7 Category 4 Appendix E.1

Standards

Requirements

ISO 13849-1:2015

6.2.6 Category 3

6.2.7 Category 4

Appendix E.1

This function block converts two antivalent BOOL inputs (NO/NC pair) to one BOOL output with discrepancy time monitoring. This FB should not be used stand-alone since it has no restart interlock. It is required to connect the output to other safety related functionalities.

Table 1003: FB name: SF_Antivalent
Name	Data type	Initial value	Description, parameter values
VAR_INPUT
Activate	BOOL	FALSE	⮫ Table 992 “General input parameters”
S_ChannelNC	BOOL	FALSE	Variable. NC stands for normally closed. Input for NC connection. FALSE: NC contact open. TRUE: NC contact closed.
S_ChannelNO	BOOL	TRUE	Variable. NO stands for normally open. Input for NO connection. FALSE: NO contact open TRUE: NO contact closed
DiscrepancyTime	TIME	T#0ms	Constant. Maximum monitoring time for discrepancy status of both inputs.
VAR_OUTPUT
Ready	BOOL	FALSE	⮫ Table 993 “General output parameters”
S_AntivalentOut	BOOL	FALSE	Safety related output. FALSE: Minimum of one input signal "not active" or status change outside of monitoring time. TRUE: Both inputs signals "active" and status change within monitoring time.
SafetyDemand	BOOL	FALSE	Optional. ⮫ Table 993 “General output parameters”
Error	BOOL	FALSE	⮫ Table 993 “General output parameters”
DiagCode	WORD	16#0000	⮫ Table 993 “General output parameters”

Typical timing diagrams

SF_Antivalent_TimingDiagram_1 — Fig. 492: Typical timing diagram for SF_Antivalent

SF_Antivalent_TimingDiagram_2 — Fig. 493: Typical timing diagram for SF_Antivalent with exceeding the DiscrepancyTime

Error detection

The function block monitors the discrepancy time between channel NO and channel NC.

Error behavior

The output S_AntivalentOut is set to FALSE. Error is set to TRUE. DiagCode indicates the error states.

There is no reset defined as an input coupled with the reset of an error. If an error occurs in the inputs, one new set of inputs with the correct value must be able to reset the error flag. (Example: If a switch is faulty and replaced, using the switch again results in a correct output.)

Function block-specific error and status codes

Table 1004: FB-specific error codes
DiagCode	State name	State description and output setting
C010	Error 1	Discrepancy time elapsed in state 8802. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = FALSE Error = TRUE
C020	Error 2	Discrepancy time elapsed in state 8804. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = FALSE Error = TRUE
C030	Error 3	Discrepancy time elapsed in state 8806. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = FALSE Error = TRUE

Table 1005: 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_AntivalentOut = FALSE SafetyDemand = FALSE Error = FALSE
8801	Init	An activation has been detected by the FB and the FB is now activated. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = TRUE Error = FALSE
8000	Safety Output Enabled	The inputs switched to the Active state in antivalent mode. Ready = TRUE S_AntivalentOut = TRUE SafetyDemand = FALSE Error = FALSE
8802	Wait for NO	ChannelNC has been switched to TRUE - waiting for ChannelNO to be switched to FALSE; discrepancy timer started. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = TRUE Error = FALSE
8804	Wait for NC	ChannelNO has been switched to FALSE - waiting for ChannelNC to be switched to TRUE; discrepancy timer started. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = TRUE Error = FALSE
8806	From Active Wait	One channel has been switched to inactive - waiting for the second channel to be switched to inactive too. Ready = TRUE S_AntivalentOut = FALSE SafetyDemand = TRUE Error = FALSE