1691

Common Causes

• Internal failure of Rotary encoder 1 (illegal control parameter, synchronization mistake, or CPU fault codes 80-FF)
• Degraded encoder signal: A/B face AD offset voltage drift or abnormal signal amplitude
• Illegal excitation output inside the encoder

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XX bit7 = Encoder alarm active; code XX bit6 = Communication error; code XX=8X = Output amplitude normal; code XX=9X = Output amplitude small; code XX=AX = Output amplitude large; code XX=BX = Output amplitude too small; code YY=00 = Not started; code YY=01 = Stopped by stop command
2. 2Read the XX status byte: bit7 set means an encoder alarm, bit6 means a communication error; 8X means output amplitude is normal while 9X/AX/BX indicate small, large, or far-too-small amplitude - amplitude faults point to a deteriorating encoder.
3. 3Read the YY alarm code to identify the internal fault: 02 illegal control parameter, 0E synchronization mistake, 0F illegal excitation output, 11-17 A/B face AD offset voltage decrease or rise, 25-2F excessive or insufficient signal amplitude, 80-FF internal CPU fault.
4. 4Lock out the machine before working near the axis, then check the encoder's connector and cable for looseness or contamination, since a poor connection can cause communication (bit6) and amplitude errors.
5. 5Per the manual's corrective action, replace Rotary encoder 1 - internal offset, amplitude, excitation, and CPU faults are not field-repairable.
6. 6If the alarm returns after encoder replacement, record the alarm number, object, and full XXYYZZZZ code and contact Okuma service.