SF_Antivalent (FB)ΒΆ

FUNCTION_BLOCK SF_Antivalent

This function block converts two antivalent SAFEBOOL inputs (NO/NC pair) to one SAFEBOOL 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.
Function block according to PLCopen, Technical Committee 5: Safety Software (Technical Specification), Part 1: Concepts and Function Blocks, Version 2.01 (2020-2)
InOut:

Scope

Name

Type

Initial

Comment

Input

Activate

BOOL

FALSE

Activation of the FB.

S_ChannelNC

BOOL

FALSE

Input for NC (Normally Closed) connection. FALSE: NC contact open, TRUE: NC contact closed.

S_ChannelNO

BOOL

FALSE

Input for NO (Normally Open) connection. FALSE: NO contact open, TRUE: NO contact closed.

DiscrepancyTime

TIME

TIME#0ms

Maximum monitoring time for discrepancy status of both inputs

Output

Ready

BOOL

FALSE

Activation of the FB. TRUE indicates that the FB is activated and the outputs results are valid, FALSE the FB is not active and the program is not executed.

S_AntivalentOut

BOOL

FALSE

Safety related output

SafetyDemand

BOOL

FALSE

Output indicating that the FB is active and the primary safety function is demanded (e.g. related to the safety functionality).

Error

BOOL

FALSE

Error flag

DiagCode

WORD

0

Diagnostic register