You can log with the ADC-212 in this mode to accomplish what you are trying to do, you can log for days, you will be limited on how long you can long by how much hard drive space you have.
If you do not need to delay the restart of the logging for 30 seconds and instead start logging again as soon as the trigger is met again you may also use PicoScope 5. Using the save on trigger function you may do this. Some are more comfortable with the interface of PicoScope 5 more than PicoLog hence the reason why I bring this up.
For upgrading your current scope to a USB model you should look at the PS3224, PS3424, PS4224 and the PS4424 models. These are all USB connected and powered units. The deeper buffer sizes on all of these models will greatly impress you compared to the ADC-212's that you currently own. You can quickly compare the specs online at http://www.pc-oscilloscopes.com/oscillo ... rison.html
to compare the actual number of samples you will see on the screen.
If you need any help deciding between a certain model, or need help setting up the software to log like you are needing feel free to post your questions here, call Pico's Technical Support line, or give us a call...
Crag Technologies, Inc