prorealtime screener code help

dear all,

i need help for an easy prorealtime screener code:

after 30 trading minutes the peak or the low will be marked.

I need a screener which notifies me at least 30 minutes shortly before the peak or the low is reached.

e.g.
highest peak after 30 minutes was 30 $
screener notifies at 28$ after X minutes

THANKS!