Dividing For..Do Loop into multiple cycles

Hi

Pseudocode showing idea below:

in our example we do 100 passes of the lfor oop in every scan

and value changes from 0 to 999 (1000 passes) which gives completion over 10 scans.

int i; // temp for counter

static int j; // static cycle counter

int k; // k is final counter value

// 1. check j in limits. reset to 0 if above or below 0.

if (j<0 OR j>MAX) then j:=0; end_if;

// 2. do FOR loop

for i=0 to 99 do // for must change from 0 to multiplier - 1. in our example multiplier is 100

k=i+100*j;// here final value is calculated

//---STATEMENTS

end_for;

j:=j+1; // increment j after FOR loop

RESULT:

1st scan - k changes from 0 to 99
2nd scan - k changes from 100 to 199
...
10th scan - k changes from 900 to 999

Please paste your FB with non-working loops used to break the work across multiple cycles up.  Be sure to highlight the code after pasting and click the "Mark as code" text modifier to help.

After "Mark as code", you can (if you choose) add spaces for indenting code like it is in your SCL editor.

// BREAK UP THE WORK DONE BY THIS LONGER SINGLE _FOR_ LOOP
// INTO 10 PASSES OF SMALLER CHUNKS OF _WORK_
//
// FOR #x := 1 TO 100 DO
//   #y := COS(#x);
// END_FOR;


#pass +=1;           // FB Static tag, Start Value = 0

IF #pass = 1 THEN
  FOR #x := 1 TO 10 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 2 THEN
  FOR #x := 11 TO 20 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 3 THEN
  FOR #x := 21 TO 30 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 4 THEN
  FOR #x := 31 TO 40 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 5 THEN
  FOR #x := 41 TO 50 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 6 THEN
  FOR #x := 11 TO 60 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 7 THEN
  FOR #x := 21 TO 70 DO
  #y := COS(#x);
  END_FOR;
ELSIF #pass = 8 THEN
  FOR #x := 31 TO 80 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 9 THEN
  FOR #x := 41 TO 90 DO
    #y := COS(#x);
  END_FOR;
ELSIF #pass = 10 THEN
  FOR #x := 41 TO 100 DO
    #y := COS(#x);
  END_FOR;
END_IF;

NOTE: This code was written live in the reply and not checked for proper syntax in the portal SCL editor.  Any mistakes are not intentional and not my responsibility if they are implemented in real PLC logic - and likely not to do anything useful.

If you want to save code, the above fully expanded FOR loop can be written like this as well:

// BREAK UP THE WORK DONE BY THIS LONGER SINGLE _FOR_ LOOP
// INTO 10 PASSES that owrk
//
// FOR #x := 1 TO 100 DO
//   #y := COS(#x);
// END_FOR;


#pass +=1;           // FB Static tag, Start Value = 0

FOR #x := (((#pass - 1) * 10) + 1) TO (10 * #pass) DO
  #y := COS(#x);
END_FOR;

I'm not suggesting the shorter version is better, but it certainly gives you thought for other approaches to breaking up longer loops (at least, that was why I added it). 

AutoGen_580188

Hello,

Thank you very much for that idea!

I tried to use the FB and it seems that it doesn't work. 

My Code isn't executed. The For Loop is doing nothing.

Did you test the code? And if you did, how did you see, that it worked?

I would like to try a working example of you.

Could you send me a working example?