Copied the bits of the MIDI Implementation PDF which you probably need to focus on...
2-2-3 KORG SYSTEM EXCLUSIVE
See "3.MIDI SYSTEM EXCLUSIVE FORMAT"
There are 22 received messages and their format is as below.
[ F0,42,3g,3B,[Func],[Data]....,F7 ]
3rd byte g : Global Channel
5th byte [Func] : Function Code ( See below Table )
Received Message List
| 41 | PARAMETER CHANGE |
Received when in
C : COMBI PLAY, COMBI EDIT mode.
P : PROG PLAY, PROG EDIT mode.
...so a SysEx Parameter Change can only be used in Combi and Prog modes.
This is the format of the SysEx message you need to send, with the lower case letters replaced with the appropriate values...
3-2 Each Exclusive message's format
R: Receive, T: Transmit
(13) PARAMETER CHANGE R
[ F0,42,3g,3B,41,0m,pp,00,qq,00,vv,ww,F7 ]
m : Mode ( Only use for mode check ) = 0:Combination, 1:Combi Edit, 2:Program, 3:Prog Edit, 4:Multi, 5:Global
pp: Parameter ID See TABLE1,2,3,4,5
qq: Parameter SUB ID See TABLE1,2,3,4,5
vv: Value (MSB bit 7..13) *1
ww: Value (LSB bit 0..6) *1
Receives this message, check the mode, select a parameter, change a value
and transmits Func= 23 message.
Replace the lower case letters in that SysEx string above with the values that match the global MIDI channel the TR-Rack is set to (I think), the mode number, the parameter you want to change, and the values you want to change it to.