Rockwell Automation 1775-KA PLC-3 Communication Adapter Module User Manual - Manual (Page 192)

Message Formats
Appendix A
AĆ30
Set Variables
Use this command to set the timeout and maximum NAKs, and ENQs all
at once. Put the timeout in the first byte of the DATA field, the NAK
setting in the second byte, and the ENQ setting in the third byte. If you do
not specify a data value for any one the variables in this command, that
variable is automatically reset to zero.
Command Format:
FNC DLE SRC STX DST C
06
S TNS
MD TS TNS DLE ETX BCC
02
DATA - 3 bytes
Reply Format:
DLE SRC STX DST C
46
S TNS
MD TS TNS DLE ETX BCC