Dear Experts,

I would like to write SCL to on/off coil by 2 timer as Ladder picture.

How to do it in SCL ?

Best Regards,

Vorapob

vorapob

Dear Experts,

I would like to write SCL to on/off coil by 2 timer as Ladder picture.

How to do it in SCL ?

Best Regards,

Vorapob

Hello.

It is difficult to guess what you are having trouble with. Showing where you are stuck would have been helpful. Please try the task again after reading the following hints.

1. The TON timer can be created in the same way as with LAD:
   * drag-and-drop from the instruction toolbox.
   * create the DB instance as you want
   * fill out the parameters as you want.
   
   
2. The alternate method is creating a timer inside an FB:
   * create a tag (myTimer) of type IEC_TIMER in STAT
   * call the tag with a TON in the code .. #myTimer.TON
   * press the keyboard keys SHIFT + SPACEBAR to reveal all the parameters
   * fill out the parameters as you want.

Show the forum what you have achieved and where you are stuck, if more help is needed.

Dear Sir,

I do like  this but it not work.

PT := T#10s);

"Timer2".TON(IN :=  "IEC_Timer_0_DB".Q,

PT := T#10s);

How can I should to do ?

vorapob

Dear Sir,

I do like  this but it not work.

"IEC_Timer_0_DB".TON(IN := NOT "Timer2".Q,

PT := T#10s);

"Timer2".TON(IN :=  "IEC_Timer_0_DB".Q,

PT := T#10s);

How can I should to do ?

Thank you -- your reply has been informative.

 "IEC_Timer_0_DB" is a DB that you have used before. So make very sure that it is still not in use anymore. The call for a timer should be unique. The quickest way to do that is to create new instances.

Re-using a timer has another problem. The timer is only started when it sees a transition from FALSE to TRUE. Deleting a timer from code, does not retrigger the IN pin of the timer. This is unrelated to SCL; it is about the timer itself.

Another hint worth mentioning is to add a tag to Q and ET pins. These tags can be TEMP tags. This is useful to track what the timer is doing. For example, my code has #_done and #_elapsed that is called with the timer for every timer. Elsewhere in the code I am using the output of the timer like #myTimer.Q much like you have done in your own code.

See if these ideas help you.

Add the source code from the attached ZIP to a project.
This should be helpful as a sample.

HINT: Add to "External source files".
Right click the source and select to add it into the project.

0_Einstein

Perhaps something closer to this:

"Timer1_DB".TON(IN:=T2_Q, PT:=T#10s);

"Timer2_DB".TON(IN:=T1_Q, PT:=T#10s);

T1_Q := "Timer1_DB".Q;
T2_Q := "Timer2_DB".Q;

 This causes the timer to be "evaluated" every scan, once and only once.  Having the evaluation hidden inside the timer call does not cause the timer to get evaluated for the Q output.

Check the TON timer F1-Help documentation notes. 

Hello Einstein,

Why is the the #T1_Q and #T2_Q tags not inside the timers? Or is it to keep compatibility with another PLC brand?

~ 

0_Einstein

Versatility, and the OP/TS stated they could not get it to work.  By having the timer inputs external to the timers forces the timer evaluations in a single location and allows experimentation and use of the trace function in a consistent manner.

By using the PLC trace function, you can see exactly how the timers are acting.  Once the timer behavior is fully understood, they can be used as the OP/TS needs. 

Nice idea for using the TRACES function.
Evaluating the timer instance is possible in TRACES. 

Though splitting hairs, writing the code as follows works the same as your suggestion. 

"Timer1_DB".TON(IN := #T2_Q,
                PT := T#10s,
                Q  => #T1_Q);

"Timer2_DB".TON(IN := #T1_Q,
                PT := T#10s,
                Q  => #T2_Q);

The way you coded, is a must when coding structured text for something like a Rockwell Micro800. That coding format is a good idea if you want to have something more universally usable between PLC brands.

Dear Experts,

Thank you for your suggestion it is very benefit idea.