If you click on the handy opiate conversion chart link that is in my signature you should be able to confirm the equivalency for DHC and most other opiates too
^This. Remember, however, that any and all charts, conversion tables, calculators, etc, are just a starting point. Everybody reacts differently to every substance.
You can't have exact conversion between ER and IR forumations. If you defeated the time release, they'd be close to 1 pill:1 pill orally of the 10mg morphine and 30mg DHC.
As has been said, there are readily available resources for conversion (I prefer the link psychopath posted because it does the math for you ).
Since everything that can be said regarding where to find this information and the limitations of such (keep in mind, these are averages and there is some variability), I'm going to close this. Feel free to PM me if you have any questions.