text: <s>[INST] Power Flex 755 Fault Codes 16 #204 , #926 Summary: Recommend to upgrade 755 firmware from 9.001 to 11.001. For a Network issue????Fault [/INST] Haven't a clue what the difference is; you could look at the firmware release notes: http://literature.rockwellautomation.com/idc/groups/literature/documents/rn/750-rn037_-en-p.pdf http://literature.rockwellautomation.com/idc/groups/literature/documents/rn/750-rn033_-en-p.pdf It very well could be they discovered a problem in 9 with memory management and fixed it in 11. I have personal experience with the early firmware releases for 755 drives running CIP motion. In version 1, the Ethernet port could only handle about 10,000 packets per second, while a simple discover query using RS-Linx could send over 30,000 packets per second. There were about 4 firmware releases in 2011 as Rockwell frantically patched serious flaws in the 755 product line. \\n </s>