Beckhoff KS6031 Documentation page 44

Access from the user program
Word alignment: In order for the channel address range to commence at a word boundary, empty bytes are
inserted into the process image as appropriate.
SB / SW: Status byte / Status word for channel n (appears in the input process image)
CB / CW: Control byte for channel n (appears in the output process image)
reserved: This byte is assigned to the process data memory, although it has no function.
44 Version: 2.1.0 KL6031/KS6031, KL6041/KS6041