In two of 21 Rackspaces, Midi Input DSI REV2 (CH2) don’t receive CC7 (Volume) from expression pedal connected to DSI Rev II. That two rackspaces have each two Midi Ins from Roland A88 (CH1) with split settings (picture Rackspace 4 + pict. Rackspace 18).
In all other Rackspaces there are only one Midi In Roland A88 and Midi In DSI REV2 (pict Rackspace 1). In that 19 Rackspaces, Midi In DSI REV2 receive CC7.
Huh? According to that MIDI Assignment list, Controller 7 on MIDI channel 2 is in fact assigned to a Widget called Gain.
If you open the global MIDI monitor and move your expression pedal, what does it show?
Yes – as a general rule, you should use host automation rather than MIDI messages to control parameters. Also, when it comes to controlling volume, unless there is a very specific need, you should not control the volume of the plugin itself, instead you should use a GP Gain control (or the GP Mixer plugin) and control volume though that.