2170

Common Causes

• Failed magnetic encoder or damaged encoder wiring
• Excessive gap between the magnetic encoder head and its gear
• Mismatch between the actual PG gear tooth count and the value in the servo data file
• Abnormal A-phase or B-phase signal voltage from the encoder

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code XXXX=A = A-phase voltage is abnormal; YYYY shows the measured A-phase voltage; code XXXX=B = B-phase voltage is abnormal; YYYY shows the measured B-phase voltage; code XXXX=C = Magnetic encoder data error; YYYY is fixed at 0; code XXXX=other = Servo data file setting (PG gear teeth x 4 - 1) at the time of a count-over error; YYYY shows the detected count from the magnetic encoder
2. 2Read the code: XXXX=A means abnormal A-phase voltage, B means abnormal B-phase voltage, C means a magnetic encoder data error; any other XXXX value is the servo data file setting (PG gear teeth x 4 - 1) captured when a count-over error occurred, with YYYY showing the actual detected count.
3. 3If XXXX is A or B, check the magnetic encoder wiring and connectors for the flagged axis for looseness, broken conductors, or oil contamination.
4. 4Inspect the physical mounting: measure the air gap between the magnetic encoder head and the gear, and look for a damaged, dirty, or demagnetized gear; correct the gap or clean/replace the gear as needed.
5. 5If XXXX is C or a gear-teeth value, compare the actual number of teeth on the PG gear against the servo data file setting and correct the mismatch (the manual lists this mismatch as a probable cause).
6. 6If wiring, gap, and gear data are all correct, replace the magnetic encoder; if the alarm still returns, record the alarm number, code, and object and contact Okuma service.