Ondelay in step7

Hello all

I have some code in a function, that has to be executed 4 sec. after the function is called…...

Anyone knows how this is done ?

Hello, Tsørensen ;

Use the S_ODT timer function :

Hope this helps,
Daniel Chartier

Daniel,

you're right. It can be done with an on-delay timer.

It can also be done with the time-delay interrupt OB's (OB20 to OB23). The advantage of this method is that the PLC doesn't waste time evaluating the timer instructions while there is nothing to do. The OB is only called upon when the interrupt has been started and the set time is over.

Kind regards,

he Assign On-Delay Timer Parameters and Start instruction starts a specified timer if there is a rising edge (change in signal state from 0 to 1) at the Start (S) input. A signal change is always necessary to start a timer...


I call the block from S7-GRAPH, and the timer should start when the block i called...what do I use as startsignal to the timer ?

Hello Tsørensen;

If you are using S7-Graph (and this is information you could have given at the beginning...) there are integrated delay instructions that you can use to start an action after a the start of a Step. (Actually, there are 2: delay before the activation, or time duration of the action after he beginning of the Step).
I do not have my S7-Graph manual available here, but I think you muast use the "D" instruction, with a duration, on the action you wish to delay. Look it up in the online help, or in the programming manual for S7-graph.

Hope this helps,
Daniel Chartier

Hello Tsørensen;
The following information should explain the delay function more clearly:
Hope this helps,
Daniel Chartier

Thanks.... that was just what I was looking for (sorry I forgot to mention I was using S7-GRAPH)