Okuma OSP codes
AxisMD

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Okuma OSP Controller

Servo/Axis · Intermediate

Alarm 3689

Okuma OSP Alarm C 3689 - MCS Rotary encoder 2 error

The MCS drive detected illegal data in Rotary encoder 2 (INA-BEARING type) on the indicated axis. The on-screen code identifies whether the A-phase or B-phase voltage read from the encoder is out of range, pointing to an encoder internal fault.

Okuma OSPServo/AxisIntermediate

3689

Okuma OSP Alarm C 3689 - MCS Rotary encoder 2 error

MCS Rotary encoder 2 error

The MCS drive detected illegal data in Rotary encoder 2 (INA-BEARING type) on the indicated axis. The on-screen code identifies whether the A-phase or B-phase voltage read from the encoder is out of range, pointing to an encoder internal fault.

Common Causes

  • Failed Rotary encoder 2 (INA-BEARING)
  • A or B phase signal voltage drifted outside valid range inside the encoder
  • Encoder cable/connector fault corrupting the phase signals

Troubleshooting Steps

  1. 1Read the code number shown with the alarm: code 000A (hex, in XXXX) = Illegal A-phase voltage data; YYYY shows the A-phase voltage value; code 000B (hex, in XXXX) = Illegal B-phase voltage data; YYYY shows the B-phase voltage value
  2. 2Read the code on screen: the upper half (XXXX) tells which phase is bad — 000A hex means illegal A-phase voltage, 000B hex means illegal B-phase voltage; the lower half (YYYY) is the actual faulty voltage value.
  3. 3Note the axis in the alarm object, then lock out power and let the drive discharge.
  4. 4Inspect the Rotary encoder 2 cable and connector for damage, contamination, or loose contact and reseat.
  5. 5If the same code returns, replace Rotary encoder 2 (INA-BEARING) as the manual directs.
  6. 6If replacement does not cure it, record the alarm number, full code, and axis and contact Okuma service.

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