In SFC I can call action with qualifiers like P0, R, S, N, LD, ... It means that there is a way to apply qualifier to action, but in ST if I can action like

myAction(S);

I get error during compilation.

How can I call an action with qualifiers in ST?

Originally created by: scott_cunningham

ST doesn't work that way. The IEC qualifiers are really replacement for ST code to make SFC easier to manage (LD has some similar items).

For example, and IEC action (action code or boolean var) without a qualifier looks like this in ST:

MyAction();

or

Done := TRUE;

If you use the set qualifier (S), it would be something like this:

IF DoOnce= TRUE THEN
   MyAction();
   DoOnce := FALSE;
END_IF

or

IF DoOnce = TRUE THEN
   Done := TRUE;
   DoOnce := FALSE;
END_IF

What if I have impulse and I have a trigger. On raise I want to start action and perform it before other signal.

VAR
    xSignal1: BOOL;
    xSignal2: BOOL;
    xWork: BOOL;
    fbRT1: R_TRIG;
    fbRT2: R_TRIG;
END_VAR
fbRT1(CLK := xSignal1);
fbRT2(CLK := xSignal2);
IF fbRT1.Q THEN
    xWork := TRUE;
END_IF; 
IF fbRT2.Q THEN
    xWork := FALSE;
END_IF; 
IF xWork THEN
    actMyAction();
END_IF; 

This simple task and code is huge. I hoped to shorten it few lines.

VAR
    xSignal1: BOOL;
    xSignal2: BOOL;
    xSignal1M: BOOL;
    xSignal2M: BOOL;
END_VAR
IF fxSignal1 AND NOT xSignal1M THEN
    actMyAction(S);
END_IF; 
xSignal1M := xSignal1;
IF xSignal2 AND NOT xSignal2M THEN
    actMyAction(R);
END_IF; 
xSignal2M := xSignal2;

That would really make some things simpler.

Check this:
https://help.codesys.com/webapp/_cds_ex ... n=3.5.14.0
https://help.codesys.com/webapp/_cds_ex ... n=3.5.14.0 m