Hold a "For instruction" for X time

[Artz]

I want to use a For instruction on a rung that changes variables during a specific time. Doesn't matter if it's by ST or LADDER.

Something like:
 

For i := 0 to 5 Do

Variable1 := Struct[i].variable1
Variable2 := Struct[i].variable2
VariableX := Struct[i].variableX
...

TON_instance(IN:=True, PT:=variable_in_seconds, Q=>TimeUp);

<HOLD FOR UNTIL TimeUp := True>

End_For;

 

[panic mode]

For i := 0 to 5 Do

Variable1 := Struct[i].variable1
Variable2 := Struct[i].variable2
VariableX := Struct[i].variableX
...

TON_instance(IN:=True, PT:=variable_in_seconds, Q=>TimeUp);


; use loop to wait...
REPEAT
 ; do nothing... just wait
UNTIL TimeUp

End_For;

[Artz]

Will try that thank you! Does that somehow interrupts the rest of the program or it's totally safe?

[Michael Walsh]

I would recommend this:

Once the ConditionForRunningLoop turns on, the For Loop will run for 5 seconds and then stop.

 

 

[Crossbow]

Careful doing a loop in text.  That loop will in sturctured text will run an infinite number of times and crash the PLC on a watchdog timer.  

ST doesn't process like ladder where it reads it once and moves on.  It's there at the point in the code forever... then crash.

Mr. Walsh has the correct idea...

[Artz]

Yup, thank you for the responses, i'm going to try "Michael Wash" method since "panic mode" one did not work as intended.