FB_BA_Alm

The FB_BA_Alm represents an alarm function block with switchable alarm memory and acknowledgment.

without alarm memory (bRstReqd = FALSE)

T1: The function block is not enabled (bEn = FALSE). A message at input bIn has not effect on the alarm output bQ.
T2: The function block is enabled (bEn = TRUE). The alarm output bQ remains set as long as the message is active at input bIn.

with alarm memory (bRstReqd = TRUE)

T1: The function block is not enabled (bEn = FALSE). A message at input bIn has not effect on the alarm output bQ.
T2: The function block is enabled (bEn = TRUE). A rising edge at message input bIn sets the alarm output bQ. It can be reset through a rising edge at reset input bRst, but only if the message is no longer active at bIn.
T3: As a rule, alarm messages at bQ are only present as long as the function block bEn is enabled.

Syntax

FUNCTION_BLOCK FB_BA_Alm
VAR_INPUT
  bEn                     : BOOL;
  bIn                     : BOOL;
  bRstReqd                : BOOL;
  bRst                    : BOOL;
END_VAR
VAR_OUTPUT
  bQ                      : BOOL;
END_VAR

Inputs

Name	Type	Description
bEn	BOOL	Enable function block.
bIn	BOOL	Message input
bRstRqd	BOOL	Alarm memory activation (requires acknowledgement).
bRst	BOOL	Edge-triggered input for resetting the alarm.

Outputs

Name	Type	Description
bQ	BOOL	Alarm output

Requirements

Development environment	Required PLC library
TwinCAT from v3.1.4024.62	Tc3_BA2 from v5.5.18.0