Off Delay with no time extension

Hi,

I am trying to make an off-delay where a further pulse on Trg before the time has elapsed does not increase the time of the off-delay - so I basically want to ignore any inputs on Trg until after the count to the delay time T has finished.

I have tried using different timers and also using a pulse generator with a counter but can't figure it out.

The simple example is attached but of course it you pulse the input and Trg at 4 seconds for example it gives a further 5 seconds which I do not want. 

Thanks in advance!

Justin

Hi Again,

I think I have the answer using a latching relay.
For a simple thing it was tricky! Maybe there is a easier way to do?

For other users with the same requirement..see the attachment

I will add the LSC below