Okuma OSP codes
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Okuma OSP Controller

Servo/Axis · Intermediate

Alarm 2689

Okuma OSP Alarm B 2689 - MCS Rotary encoder 2 error

The MCS detected illegal data from rotary encoder 2 (INA-BEARING type) on the axis named in the object field. The code on screen tells which internal channel (A or B aspect voltage) was out of range, pointing to a failing encoder element or signal problem.

Okuma OSPServo/AxisIntermediate

2689

Okuma OSP Alarm B 2689 - MCS Rotary encoder 2 error

MCS Rotary encoder 2 error

The MCS detected illegal data from rotary encoder 2 (INA-BEARING type) on the axis named in the object field. The code on screen tells which internal channel (A or B aspect voltage) was out of range, pointing to a failing encoder element or signal problem.

Common Causes

  • Failing INA-BEARING rotary encoder 2 with out-of-range A or B aspect voltage
  • Encoder cable damage or connector contamination
  • Electrical noise or supply problem affecting the encoder signal

Troubleshooting Steps

  1. 1Read the code number shown with the alarm: code 000A (hex, upper) = Illegal A aspect voltage; lower half shows the measured A voltage; code 000B (hex, upper) = Illegal B aspect voltage; lower half shows the measured B voltage
  2. 2Read the code on screen: the upper half 000A hex means the A aspect voltage was illegal, 000B hex means the B aspect voltage was illegal, and the lower half shows the actual voltage value measured.
  3. 3Lock out power, then inspect and reseat the rotary encoder 2 connector on the named axis, checking for coolant or metal chips inside the plug.
  4. 4Examine the encoder cable along its full run for pinch points in the drag chain or contact with moving covers.
  5. 5Power up and jog the axis slowly; if the same aspect voltage error returns, the encoder element itself is degrading.
  6. 6Replace rotary encoder 2 (INA-BEARING) as the manual directs once cabling has been ruled out.

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