Moinmoin,
to my experience the P08 MIDI-implementation is very stable. I tried all "normal" MIDI commands, some not so common ones like NRPNS and if I remember right even some that are not documented in the P08 manual, but seemed like "should work" and everything worked as it should.
But no, I am no Logic-expert, although using it sometimes as a "sidekick" of master-user Peter Sonntag during recording or remixing of our band's (Final Virus) music. Using Logic as a MIDI sequencer (we use it more as a recording and producing tool for "real" instruments, only sometimes supported by MIDI-features) You have to look at some things, one of them being the MIDI loop.
The behaviour described may result from breaking the MIDI-connection in Logic
and at the P'08 side:
If "Local Control" in the P'08 general setting is set to OFF, the P'08 will react only to MIDI-commands from its MIDI in,
not on its own keyboard and/or knobs! Everything touched at the P'08 will be sent to its MIDI out
only.
If in this situation the MIDI echo at the Logic side is set to OFF, Logic will
not send back on its MIDI out to P'08's MIDI in, what it received from P'08's MIDI out.
This results in effecticely separating the P'08 "user interface" (keys, knobs, controllers) from theP'08 "sound source" (VCO, HADSR, VCF, VCA, LFO, ...).
There are some other MIDI commands like "active sensing", which may interrupt the link between "user interface" and "sound source". "Active sensing" requires a sort of lifecheck signal regularly exchanged between the MIDI-partners. If this lifecheck fails, all sounds are switched off and the connection hangs.
Unlike timbo74 I am a fan of looking into MIDI dumps if I have problems. In Your case:
- are there any key messages entering Logic, if You press P'08 keys?
- are there any NRPNS (or CCs, whatever You configured in P'08 global settings) entering Logic if You tweak P'08 knobs?
- are there any key messages leaving Logic, if P'08 should play, but doesn't?
- are there any NRPNs od CCs leaving Logic, if P'08 parameters should change, but don't?
If You checked P'08 "Local Control" and Logic "MIDI echo" (Only
one of them may be OFF!) and the P'08 still remains quiet, check Logic's input and output for the listed topics.
HTH
Martin