switching between to outputs, fast and timed

I am currently working on a shaking machine to remove metal parts after they have been punched on a punch press. I can't seem to figure out how to make the pnumatic ram osilate back and forth. I have an output for both sides of the ram. I would like to set up a time sequence for the length of operation. I would apreciate any help.
Thanks

I forgot to mention that I am using an idec microsmart 24 plc. I have entended to use timers to control the changes in setting and resetting the outputs for osilating the pnumatic ram. I was hoping since I am a novice at this some one could possibly suggest a cleaner route than creating all the different timers.
Thanks,

Sounds like your looking for a flip flop. Do a search for flip flops.

Bob O.

Two timers. Use the DONE bit of the first (NO contact)to enable the second. Use the DONE bit of the second (NC contact) to enable/reset the first. Use a NO contact from the DONE bit of the first timer to energize one of the solenoids. Use a NC contact from the DONE bit of the same timer in series with the TIMING (enabled) bit (NO contact) to energize the other solenoid. The preset values for the timers establish the on times for the two solenoids. Add some logic to disable all timing and shut off both solenoids and you're good to go.