Fanuc 366 Alarm _verified_ -

: Because the built-in pulse coder is located under the red cap on the motor and requires precise alignment, it is rarely repaired in the field. The most reliable way to confirm the fault is to swap the motor

Dust, oil, or coolant on the glass scale inside the pulse coder. fanuc 366 alarm

phases) or the absolute serial data check-sum failed momentarily. : Because the built-in pulse coder is located

The drive has detected a loss of pulse data integrity from the built-in pulse coder. Signal Interference: fanuc 366 alarm

FANUC Troubleshooting Manual – FANUC CNC FAQ - MRO Electric

Incorrect timer constants cause alarm 366. For example: