Internet PLC Forum

Ok I am very new to the PLC ladder logic world so forgive me if this is too easy for most of you. I have an application where I need to trigger an output every 30 min to keep a system from going to sleep. What I need is a timer that will start on the first pass of the ladder, run for a specified period of time, then automatically reset and run again. This loop needs to be continuous as long as the plc is powered. Any help is appreciated.

Thanks

Mike