I'm pretty sure we will need more info about the procedure you are following before a better method could be suggested.
Using the workflow and workflow states is key in PDM Std or Pro.
The simplest workflow which handles revisions, has two states, e.g. "In Work" and "Released". There will be one option for State Change in "In Work", which is "Approve". There will be one option for State Change in "Released", which is "Change".
Revisions will be given during the Approve transition. Like this:
Check ins and check outs will happen in "In Work" only. Documents are locked from check out/editing in Released state.
Check ins create historic versions of the file, not revisions. While the file resides in "In Work", every Check In with a change of contents, will create a new version. The file you send to Released can therefore be version 300, but as long as it's getting it's first release, Revision counter will stamp it with 1 or A, or whatever you decided your Revision Scheme to be, when sent to "Released".
It doesn't have to be harder than that, but most workflows will add a "Check" state in between, to get a second opinion/approval of your design.