3170

Common Causes

• Failed magnetic encoder or damaged encoder wiring
• Excessive gap between the magnetic encoder head and its gear
• Gear tooth count in the servo data file not matching the actual magnetic encoder gear
• Abnormal A-phase or B-phase signal voltage from the sensor

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XXXX=A = A-phase voltage abnormal; YYYY shows the A-phase voltage; code XXXX=B = B-phase voltage abnormal; YYYY shows the B-phase voltage; code XXXX=C = Magnetic encoder data error; YYYY is fixed at 0; code XXXX=other = Servo data file set value (PG gear teeth x 4 - 1) at a count-over error; YYYY shows the detected count
2. 2Read the code: XXXX=A means abnormal A-phase voltage, B means abnormal B-phase voltage (YYYY shows the measured voltage), C means magnetic encoder data error; any other XXXX is the servo file set value (PG gear teeth x 4 - 1) captured at a count-over, with YYYY showing the actual detected count.
3. 3If XXXX is A or B, check the magnetic encoder wiring and connector for opens or shorts and measure/inspect the sensor output; a bad phase voltage points to the sensor or its cable.
4. 4Inspect the mounting of the magnetic encoder head: verify the air gap to the gear is within spec and that the gear teeth are clean and undamaged.
5. 5If the code shows a count mismatch (XXXX/YYYY as gear teeth x 4 - 1 values), confirm the actual gear tooth count matches the servo data file setting for that axis; correct the data file or the hardware mismatch.
6. 6If wiring, gap and tooth count are all correct, replace the magnetic encoder; if the alarm persists record the code and object and contact Okuma service.