Is there a timer function or variable in Codesys as in arduino millis()? - codesys

Question

Is there a timer function or variable in Codesys as in arduino millis() ?
If not, how can I create a timer?
Thanks!

Answer 1

In CoDeSys function TIME() return time in milliseconds from PLC start. If you want to start the count on the event you can use triggers to create a time point.
VAR
tStarted, tElapsed : TIME;
END_VAR
fbR_TRIG(CLK := xStart);
IF (fbR_TRIG.Q) THEN
tStarted := TIME();
END_IF;
tElapsed := TIME() - tStarted;
And rest follows like reset the timer, pause counting, etc.

Answer 2

You can build one yourself.
Here an example:
Declaration part:
FUNCTION_BLOCK FB_Millis
VAR_INPUT
timer : TON := (IN:=TRUE,PT:=maxTime);
END_VAR
VAR_OUTPUT
tElapsedTime : TIME;
END_VAR
VAR
maxTime : TIME := UDINT_TO_TIME(4294967295);
//timer : TON := (IN:=TRUE,PT:=maxTime);
END_VAR
Implementation part:
timer();
tElapsedTime := timer.ET;
You call it cyclically like this:
fbMillis();
And retrieve the result like this:
tElapasedTime := fbMillis.tElapsedTime;
FB_Millis overflows after 49days 17hours 2minutes 47seconds and 295ms.
If you want to compare the elapsed time from fbMillis.tElapsedTime with another variable you do like this:
IF fbMillis.tElapsedTime < tAnotherTimeVar
THEN
; //Do something
ELSE
; //Do something else
END_IF
If you instead just want a simple timer you need the TON Function Block:
Declaration part:
//2 seconds timer
mySimpleTimer : TON := (PT:=T#2s);
Implementation part:
mySimpleTimer();
// your code here
//Start timer
mySimpleTimer.IN := TRUE;
//Check if timer has reached desired time
IF mySimpleTime.Q
THEN
//Do something here
mySimpleTimer.IN := FALSE;
END_IF