Hello Laurens,
Assuming you're using Hauptwerk v6:
- Before connecting the new Launchpad, in Hauptwerk go to the 'General settings | MIDI ports | MIDI IN ports' screen tab. Make sure you've specified a meaningful 'User alias' for the row in which your existing Launchpad's column is ticked, so that you'll be able to tell it apart later. For example, you could name the existing Launchpad's row something like 'Left stop-jamb Launchpad', if that's what you'll be using it for. Do likewise on the 'MIDI OUT ports' tab, then OK the screen.
- Exit Hauptwerk.
- Connect the new Launchpad. (Never connect/disconnect audio, MIDI or USB devices whilst Hauptwerk is actually running.)
- Re-launch Hauptwerk. It should tell you that a new MIDI device has been found, and it will then open the 'General settings | MIDI ports | MIDI IN ports' screen tab for you to confirm the settings. On that screen, leave the previous Launchpad ticked and named/aliased as before, and make sure that the new Launchpad (column) is also ticked, but in a different row from the previous one. Give its row a meaningful name too, e.g. 'Right stop-jamb Launchpad'. Do likewise on the 'MIDI OUT ports' tab, then OK the screen.
You should then be able to use them both normally.
In case the operating system ever swaps the two devices around (which sometimes happens), all you would then need to do is switch the two ticked columns for the respective rows (on both the 'MIDI IN ports' and 'MIDI OUT ports' tabs), and all of your auto-detected settings would be retained (since in Hauptwerk v6 MIDI settings are stored relative to the rows, not the MIDI device directly, thus allowing you to change the ticked columns around without needing to auto-detect everything again).