SRVO-121: Excessive acc/dec time
Internal servo alarm: the computed acceleration time came out too long - a motion-planning fault FANUC wants diagnostic data for, not something fixed at the pendant.
What it means
Internal servo alarm: the computed acceleration time came out too long - a motion-planning fault FANUC wants diagnostic data for, not something fixed at the pendant.
Common causes
Ranked by what technicians most often find, most likely first.
- Internal motion software condition; not a configuration or mechanical issue a tech can isolate on site.
How to fix it
- Run Diagnostic Log (FNCT > Diagnostic log) before any other operation, take an image backup, and contact FANUC with both. If the log can't run, document the exact events leading up to the alarm.