Allen-Bradley 1779-KFMR User Manual page 194

If a PLC-3 controller returns a value of F0 in the STS field, an additional
field (EXT STS) will contain specific error code. Table A.B lists EXT
STS codes for replies from PLC-3 controllers.
Table A.B
Hexadecimal Extended Status Codes You May Receive in the EXT STS Field of a Data
Highway Message Set Reply from a PLC 3 Controller
EXT STS
Code
Table A.C
Hexadecimal Status Codes You May Receive in the STS Field of a Time Critical Reply
Status
Code
Appendix A
Meaning
Meaning