Timer in ST / SCL

[userxyz]

I have an input that has to be on for 1 second before something can happen.

How can I write this in SCL ?

 

[JesperMP]

This is from SCl online help (it is for a pulse timer, but you get the idea):

FUNCTION_BLOCK TIMER



VAR_INPUT 

  mytime : TIMER ; 

END_VAR 



VAR_OUTPUT

  result : S5TIME ;

END_VAR 



VAR

  set               : BOOL ; 

  reset             : BOOL ; 

  bcdvalue          : S5TIME ;//Time base and time remaining in BCD 

  binvalue          : WORD ; //Time value in binary 

  initialvalue      : S5TIME ;

END_VAR 



BEGIN 

  Q0.0              := 1;

  set               := I0.0 ;

  reset             := I0.1;

  initialvalue      := T#25S ; 

  bcdvalue          := S_PEXT (T_NO := mytime ,

                               S    := set ,

                               TV   := initialvalue ,

                               R    := reset ,

                               BI   := binvalue ,

                               Q    := Q0.7) ; 



//Further processing as output parameter 

  result            := bcdvalue ;



//To output for display

  QW4               := binvalue ;



END_FUNCTION_BLOCK

As an alternative, you should also be able to call the IEC timers TON and TOF.

 

[JesperMP]

It can also be written much more condensed:

DelayTimer_bcd :=S_ODT  (T_NO:= T10, S:=M3.5, TV:=T#1s, R:=FALSE, BI:=MW100,Q:=M3.6);

The above example is an ondelay timer using T10, with a fixed setpoint of 1 second, input M3.5 and output M3.6

edit: The confusing bit is that the main returned value (DelayTimer_bcd), is only used for display of the remaining time in BCD format. You dont have to use it for anything.
The output you need to use is from the Q parameter.

 

[userxyz]

Jesper

Thanks again Jesper, I'm learning a lot from you,

Could I write it like this ?

VAR_INPUT
Dender: TIMER;
INPUT: BOOL;
END_VAR

VAR_OUTPUT
SEE_TIME: INT;
END_VAR

TEMP_VAR
TMP: BOOL;
END_VAR

Delay:= S_ODT (T_NO:= Dender, S:=INPUT, TV:=T#1s, Q:=TMP);

SEE_TIME:= delay // monitor time

?

It can also be written much more condensed:

DelayTimer_bcd :=S_ODT (T_NO:= T10, S:=M3.5, TV:=T#1s, R:=FALSE, BI:=MW100,Q:=M3.6);

The above example is an ondelay timer using T10, with a fixed setpoint of 1 second, input M3.5 and output M3.6

edit: The confusing bit is that the main returned value (DelayTimer_bcd), is only used for display of the remaining time in BCD format. You dont have to use it for anything.
The output you need to use is from the Q parameter.

 

[JesperMP]

I would use the BI parameter, because you then can see the time with an INT tag in stead of going via BCD.
DelayTimer_bcd :=S_ODT (T_NO:= T10, S:=M3.5, TV:=T#1s, R:=FALSE, BI:=SEE_TIME,Q:=M3.6);

edit: And you have already declared SEE_TIME as an INT, so you should use the BI output.

 

[userxyz]

k

DelayTimer_bcd :=

but this part is not needed ?

I would use the BI parameter, because you then can see the time with an INT tag in stead of going via BCD.
DelayTimer_bcd :=S_ODT (T_NO:= T10, S:=M3.5, TV:=T#1s, R:=FALSE, BI:=SEE_TIME,Q:=M3.6);

edit: And you have already declared SEE_TIME as an INT, so you should use the BI output.

 

[JesperMP]

I am not sure. You could assign it to a temporary variable.
It looks like that the way the S5 timers are called in SCL, that there has to be a return value, and this return value is the remaining time in BCD format.

Maybe it is possible to just write
S_ODT (T_NO:= T10, S:=M3.5, TV:=T#1s, R:=FALSE, BI:=SEE_TIME,Q:=M3.6);
that is, without a return value. Same as that you dont have to use the BCD output in STL.
Try it, and tell us how it goes.

 

[Ken M]

This has got to be a first! Jesper recommending the use of S5 timers! Mark this date, gentlemen - your grandchildren will want to know what you were doing on this day. Why not good old IEC "TON" timers? Declare the timer itself as a VAR (stat) and then call it as any other FB -

VAR
Dender: SFB4;
END_VAR;
 
VAR_TEMP
See_Time : TIME;
Start : BOOL:
Delay : BOOL;
END_VAR
 
Dender (IN := Start,
	PT := T#1s,
	Q := Delay,
	ET := See_Time);

I haven't patched in any other code indicating what you might do with Start, Delay or See_Time.

Regards

Ken

 

[JesperMP]

Always read to the bottom of my posts !

As an alternative, you should also be able to call the IEC timers TON and TOF.

 

[userxyz]

ok

TIJD := S_ODT (T_NO:= DEMPER, S:=INPUT, TV:=T#5s, R:=FALSE, Q:=INPUT_DELAYED);

Like this is works


S_ODT (T_NO:= DEMPER, S:=INPUT, TV:=T#5s, R:=FALSE, Q:=INPUT_DELAYED);

This doesn't work