Codesys Wait function block

[r.zarei2010]

Hi. I'm writing an CODESYS program with ST.
In diffrent parts of my main program i need my program to pause for a while and continue running after a time elapsed. So i defined Wait function block as below and reused it where it's need (multiple times):

delectation part:

FUNCTION_BLOCK Wait
VAR_INPUT
time_in:TIME;
END_VAR

VAR
ton1:TON;
END_VAR

----------------------------------
body part:

ton1(in:=TRUE,PT:=time_in);
WHILE ton1.Q=FALSE DO
ton1(PT:=time_in);
END_WHILE
ton1(in:=FALSE);

The function block works as expected, but is consume cpu very much, and watchdog stops my program.

what is the alternative way of doing this?

all i want is some thing like this:

Line 1
Line 2
Wait 5 seconds
Line 4
Wait 10 seconds
Line 6
...

Thanks.

 

[keshik]

I would use the done bit (Q) of a timer to let the next step/line continue. For example, start a timer when line 2 is complete. When that timer is complete, allow the next line to process. I would also probably use a sequence step to help keep things clean. I also find it useful to make sure that my timer are being called outside of IF statements to make sure that they are processed each PLC scan.

sequence : DINT;
t_line2Complete : TON;
line2Complete : BOOL;
firstScan : BOOL := TRUE;

IF (firstScan) THEN
    sequence := 1;  /* line 1 */
    line2Complete := FALSE;
    firstScan := FALSE;
END_IF

IF (sequence == 1) THEN
    [do line 1 things]
    sequence := 2;
END_IF

IF (sequence == 2) THEN
    [do line 2 things]
    line2Complete := TRUE;
    sequence := 3;
END_IF

t_line2Complete(PT := t#5s, IN := line2Complete);

IF ((sequence := 3) AND (t_line2Complete.Q)) THEN
    [do line 3 things]
    line2Complete := FALSE;
    sequence := 4;
END_IF
...

Hopefully that gives you an idea of something that you could do.

 

[r.zarei2010]

I would use the done bit (Q) of a timer to let the next step/line continue. For example, start a timer when line 2 is complete. When that timer is complete, allow the next line to process. I would also probably use a sequence step to help keep things clean. I also find it useful to make sure that my timer are being called outside of IF statements to make sure that they are processed each PLC scan.

sequence : DINT;
t_line2Complete : TON;
line2Complete : BOOL;
firstScan : BOOL := TRUE;

IF (firstScan) THEN
    sequence := 1;  /* line 1 */
    line2Complete := FALSE;
    firstScan := FALSE;
END_IF

IF (sequence == 1) THEN
    [do line 1 things]
    sequence := 2;
END_IF

IF (sequence == 2) THEN
    [do line 2 things]
    line2Complete := TRUE;
    sequence := 3;
END_IF

t_line2Complete(PT := t#5s, IN := line2Complete);

IF ((sequence := 3) AND (t_line2Complete.Q)) THEN
    [do line 3 things]
    line2Complete := FALSE;
    sequence := 4;
END_IF
...

Hopefully that gives you an idea of something that you could do.

Thanks for your reply. I've find better way to that by sleeping running task.

 

[shooter]

you best use SFC for this, but also possible in ST

if line 1 and line 2 done and NOT timer1.IN then Timer1.IN=TRUE....
if Timer1.Q start line4
etc.
The program must be scanning all the time.
or use state programming.