title: Cron trigger to run at half past the hour every hour
body: <p>Can anyone suggest a way to set a Cron trigger to run at half past the hour every hour?</p>
  
  <p>So far, I've got one working hourly as per "0 0/60 * * * ?".</p>
  
  <p>Am I looking at "0 0/30 * * * ?" at all?</p>
  
  <p>Mr Morgan.</p>