Hello experts:

Please see the below program:

INTERFACE

var_Global

start :bool;

A :int;

b:int;

end_var;

PROGTAM  TEST;

end_interface

implenmentation

PROGRAM TEST

VAR

rt_start :R_TRIG;

END_VAR

rt_start(start);

WHILE  RT_START.Q  DO

for a :=0 to 20 do

b:=b+1;

end_for;

end_while;

end_program

end_implenmentation

My question is :

Normaly the rt_start.q is only be true for one cycle time .

But ,in my example.   i use the ring edge as the condition of WHILE stament , wyh the    rt_start .q    is alway true???? 

Thank you very much!

winterwang

Hello experts:

Please see the below program:

 In which task you call this program?

jacek d

 

winterwang

Hello experts:

Please see the below program:

 In which task you call this program?

Hello JACKED

 i assign it in Background task.

TechTeam

Hello,

this can not be.

Please do a trace in servocycle to evaluate your behavior.

Variables:

RT_START.Q  , start and b ;

Hello TechTeam

 i attached a trace here.

and  you can find it : the Rt_start.q is True.  The b is increased.

because the loop is very long ,the watchdog time exceed. and CPU goes to STOP.

jacek d

 

winterwang

Hello experts:

Please see the below program:

 In which task you call this program?

Hello JACKE D

 EVEN i assign it to Montion_task ,

 the result is the same. only different is that there is no time monitor, and will not goes to STOP mode.

RT_START.Q is not changing back to FALSE because it is not being processed.

Once the program enters the WHILE loop it will no longer scan the call to rt_start(trigger).

If you wanted to make this work you would need to also call rt_start(trigger) from within the WHILE loop.

Like this:

rt_start(start);

WHILE  RT_START.Q  DO

    for a :=0 to 20 do

        b:=b+1;

    end_for;

    rt_start(start);

end_while;

Also, if you put a waitTime call in a while loop it will allow the processor to continue on to scan the rest of your programs and not cause it to fault out of run because it used up all of your processing time.

rt_start(start);

WHILE  RT_START.Q  DO

    for a :=0 to 20 do

        b:=b+1;

    end_for;

    rt_start(start);

    myRetDINT := _waitTime(t#0ms);

end_while;

winterwang

 

jacek d

 

winterwang

Hello experts:

Please see the below program:

 In which task you call this program?

Hello JACKE D

 EVEN i assign it to Montion_task ,

 the result is the same. only different is that there is no time monitor, and will not goes to STOP mode.

 I can't tell you why I missed it for first time...

The problem is, that you don't call the timer inside the WHILE loop. So it never quits.

Other story is that's not the encouraged programming technique...

I was also thinking that this may have been an April fools joke.

It is pretty funny.