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Trigger, L-force | plc designer – Lenze PLC Designer PLC Designer (R2-x) User Manual

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L-force | PLC Designer

PLC Designer Libraries

DMS 3.2 EN 02/2011 TD29

649

19.1.3

Trigger...

R_TRIG

Provided by standard.lib.

The function block R_TRIG detects a rising edge.

FUNCTION_BLOCK R_TRIG

VAR_INPUT

CLK : BOOL;

END_VAR

VAR_OUTPUT

Q : BOOL;

END_VAR

VAR

M : BOOL := FALSE;

END_VAR

Q := CLK AND NOT M;

M := CLK;

The output Q and the help variable M will remain FALSE as long as the input variable
CLK is FALSE. As soon as CLK returns TRUE, Q will first return TRUE, then M will be set
to TRUE. This means each time the function is called up, Q will return FALSE until CLK

has falling edge followed by an rising edge.

Declaration example:

RTRIGInst : R_TRIG ;

Example in IL:

CAL RTRIGInst(CLK := VarBOOL1)

LD RTRIGInst.Q

ST VarBOOL2