Apple Logic Express 8 - Manual (Page 955)

Chapter 38 Working in the Environment 955
Setting the SysEx Data Format
The terms SUM for the checksum and VAL for the fader value being sent are displayed
within the SysEx string.
To set the checksum and value of a SysEx event:
1 Select the events you want to alter.
2 Choose the desired options in the Checksum and Value menus (found in the lower
right corner of the window) to set the format of these bytes.
Checksum Format
A checksum can be created in any of the following formats:
 Roland
 Yamaha
 Regular Checksum
 2’s complement
 1’s complement
If you don’t know which one works with your MIDI device, try “off” (= no checksum)
first or “2’s complement”.
Value Byte Position
Position allows you to determine the position of the value byte. This position is
specified in bytes, counted from the end of the message: “last” refers to the position
directly before the EOX byte, “Last-1” indicates the byte before that, and so on.
Auto ensures that the value byte is inserted at the last position in the SysEx string if no
checksum was selected, or—if a checksum value was entered—that the value is
inserted as the second to last byte.