Troubleshooting steps
Check network connections, verify controller communication, reset network
Robot Error Codes
FANUC ALARM 21 – Communication fault
Communication fault
Details
FANUC ALARM 21 error on R-30iA, R-30iB indicates communication fault. Network communication error, controller communication failure. Check network connections, verify controller communication, reset network.
Error typecommunication
MeaningCommunication fault
Typical causesNetwork communication error, controller communication failure
SolutionsCheck network connections, verify controller communication, reset network
SeverityMedium
Catalog references
Where this appears
FANUCALARM 21
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What does ALARM 21 mean on FANUC robot?
ALARM 21 on FANUC R-30iA, R-30iB indicates communication fault. Network communication error, controller communication failure.
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