The ladder on the CNC was last edited with a different version of LadderIII (e.g., 2010), causing checksum differences. Fix: In 2021, use File > Import > Re-symbolize . This strips the old symbol hash and rebuilds it from the current mnemonics.
or a Technical Blog post next.
: Real-time visualization of the ladder logic as it executes on the machine. fanuc ladderiii 2021