Okuma OSP codes
AxisMD

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Okuma OSP Controller

Servo/Axis · Intermediate

Alarm 3690

Okuma OSP Alarm C 3690 - MCS Rotary encoder 1 initialization failure

The control failed to initialize rotary encoder 1 on the reported axis during power-up or reset. This means the drive could not establish valid position feedback from that encoder, so the axis cannot be operated.

Okuma OSPServo/AxisIntermediate

3690

Okuma OSP Alarm C 3690 - MCS Rotary encoder 1 initialization failure

MCS Rotary encoder 1 initialization failure

The control failed to initialize rotary encoder 1 on the reported axis during power-up or reset. This means the drive could not establish valid position feedback from that encoder, so the axis cannot be operated.

Common Causes

  • Faulty rotary encoder 1
  • Faulty motor encoder
  • Damaged encoder link cable or loose/corroded connector
  • Faulty control base of the inverter unit

Troubleshooting Steps

  1. 1Read the code number shown with the alarm: code XXYYZZZZ = Failure detail code, interpreted the same as alarm 0865 'MCS Encoder initialize failed'
  2. 2Note the axis named in the object and record the XXYYZZZZ code; it is decoded the same way as alarm 0865 'MCS Encoder initialize failed'.
  3. 3Power down, then inspect the encoder link cable and connectors at both the encoder and inverter ends for the reported axis: reseat them and look for bent pins, oil contamination, or chafed cable.
  4. 4If the cable and connectors are good, swap or replace rotary encoder 1 (and check the motor encoder) on that axis and retry initialization.
  5. 5If the fault follows neither cable nor encoder, the control base of the inverter unit is suspect; lock out power and allow the DC bus to discharge before exchanging units.
  6. 6If it returns after these checks, record the alarm number, code and object and contact Okuma service.

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